INTELLIGENCE,
RACE, A N D
GENET
/ ¿ n je n
F R A N K MI ELE
A Member o f the Perseus Books G roup
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1— 0 5 04 03 0 2
To my latefather, Edward J. Miele,
and my mother, Cecilia Miele,
who gave me both my genes and my environment;
and to my brother, Edward F. Miele,
who shares them with me.
CONTENTS
IX
XI
Preface
Acknowledgments
INTRODUCTION
I
Jensenism and Skepticism
PRELUDE
7
T h e M an Behind the “ Ism ’
1
UENSENISM
A N ew W ord in the D ictionary
2
WHAT
17
IS I N T E L L I G E N C E ?
T h e g Factor and Its R ivals
3
NATURE,
43
N U R TU R E ,O R
BOTH?
C an H eritability C u t Psychology’s G o rd ian Knot?
4
WHAT
IS R A C E ?
B iological Reality or C ultural C onstruction?
5
FROM
THE
JEN SEN ISM
BELL C U R V E
SCIENCE
AND
109
TO
WARS
Science, Pseudoscience, and Politics
6
69
147
POLICY
W h a t’s to Be D one?
171
Appendix A: Bibliography of Arthur R. Jensen
19 1
Appendix B: Mainstream Science on Intelligence
22 3
231
Index
vu
PREFACE
“ C om pensatory education has been tried and it apparently has failed.”
W ith that opening sentence o f a 123-page-long article solicited by the
prestigious Harvard Educational Review, P rofessor Arthur R . Jensen, o f the
University o f California, Berkeley, went fro m being a highly respected but
little-known educational psychologist to one o f the m ost controversial fig­
ures in science.
W ritten in 1969 d urin g the tum ultuous days o f the rioting in the
Black inner cities and W h ite voter disenchantm ent with Lyndon Johnsons
Great Society programs, Jensen’s HER article set o f f a firestorm o f con­
troversy. T h e title, “H o w
M uch C an W e Boost I Q and Scholastic
Achievement?” and Jensen’s conclusion, “ N o t much,” m ade him a headlin­
er in Time, Newsweek, Life, U.S. News fir World Report, and The New York Times
Magazine, on the one hand, an d the target o f student protests, sit-ins, reso­
lutions o f condem nation, an d even acts o f vandalism and death threats on
the other. T h e word “Jen sen ism ”— shorth and for Jensen’s theory that an
individual’s I Q is largely due to heredity, including racial heritage— found
its way into som e dictionaries.
In this book, I skeptically cross-exam ine Arthur R . Jensen on
Jensenism— how and why he believes the scientific evidence is even
stronger to d ay that:
• I Q is real, biological, and highly genetic, and n ot ju st some
statistic or the resu lt o f educational, social, economic, or cul­
tural factors;
IX
PREFACE
X
•
race is a biological reality, not a social construct; and,
•
the cause o f the 15-point average I Q difference between
m ost controversially o f all,
Blacks and W hites in the U n ited States is partly genetic.
T h e late Stephen Jay G ould’s Mismeasure of Man, H oward G ardners
num erous books on “ multiple intelligences,” and Josep h Graves’s The
Emperor’s New Clothes argue that Jensenism and the controversial best-seller
The Bell Curve (which draws heavily on Jensen’s work) are marginal science
at best, pseudoscience at worst. Here, Jensen replies to these and other crit­
ics. H e also answers the questions I think you yourself would like to ask
him . H e tells you why he believes the scientific basis o f Jensenism is as
so lid as the R ock o f Gibraltar, why the experts in the relevant disciplines
o f behavior genetics and psychom etrics agree with him and not his critics,
and why the public has been so m isinform ed.
T h is book also introduces you to A rthur Jensen, the man behind the
“ ism ,” so that you can understand why he took up such a controversial
research program and why he has pursued it so relentlessly. Finally, it takes
you on the intellectual odyssey o f the behavioral sciences over the p ast
third o f a century, detailing the sea changes that have taken place since
Jensen and Jensenism first hit the front pages in 1969.
Frank Miele
Sunnyvale; California
ACKNOWLEDGMENTS
I could not have written this b o ok without the help and encouragement
that so many people have given me over the years. I would like to give par­
ticular thanks to publisher an d editor-in-chief M ichael Sherm er and the
s ta ff o f Skeptic, to all those who have given so generously o f their time in
allowing me to interview them for the m agazine, and to my editor Karl
Yambert and the sta ff at Westview. Additionally, the photos in the book
were provided by courtesy o f A rthur Jensen and the cover p h oto by cour­
tesy o f L o is V Jensen, his sister, and I thank them for their perm ission to
use the ph otos.
F.M .
INTRODUCTION
Jensenism and Skepticism
Jensenism, n: the theory that an individual’s IQ is largely due to heredi­
ty, including racial heritage; after A rth u r R . Jensen (b o rn
1923), U .S. educational psychologist, w ho first propoun ded
this hypothesis in 1 9 6 5 .
and
Skepticism, n: the search for provisional, not metaphysical, truth through
the continuous and vigorous application o f the m ethods o f
science, that is, form ulating hypotheses and gathering data
against which to test them .
J
ensenism and skepticism— what’s the connection? W h a t does a controversial
theory linking intelligence, race, and genetics have to do with a grow­
ing movement that prom otes better understanding o f the scientific m ethod
and greater use o f critical thinking by the general public?
O n the one hand, one skeptic icon, the late Steph en Jay G ould, w ho was
then America’s best-known science writer, a distinguished though contro­
versial scientist in his own right, an d a past president o f the Am erican
A ssociation for the Advancement o f Science, once claimed to have
debunked Jensenism as resting on “ a rotten edifice.” O n the other, Intelligence,
the m o st prestigious journal in the field o f I Q research, devoted an entire
issue to honoring Jensen and his w ork, which its editor, Douglas D etterm an,
titled “A King A m on g Men: A rth ur Jensen.”
I
2
IN TE LL IG E N C E ,
RACE, AND
GENETICS
I f these wildly varying assessm ents o f A rth ur R . Jensen and his theo­
ries o f race, genetics, and hum an intelligence d on ’t invite a skeptical exami­
nation and som e critical thinking, what does? A s senior editor o f Skeptic, I’ve
interviewed som e o f the world’s leading scholars on differing sid es o f the
race-IQ issue an d related controversies in biological and behavioral sciences.
W h o better to interview than the namesake o f the m ost controversial “ ism”
o f them all— the relation between race, intelligence, and genetics?
I realized that a fair treatment o f Jensen and Jensenism w ould require a
book, not just an article. Jensen accepted, but co u ld he com m it the time?
T h a t year, 1 9 9 9 , he was based in London, E ngland, working at the Galton
Library on biographies o f Charles Spearman an d H ans Eysenck comm is­
sioned by the Am erican Psychological A ssociation (A PA ) and delivering the
annual Galton Lecture as well as invited lectures at universities an d research
institutes in the U n ited K ingdom , Denmark, Germany, Austria, Italy, and
Spain. It wasn’t possible for m e to spend the year in Europe attending the
lectures while we did the interviews. Even long-distance phone calls pre­
sented a difficulty because o f the eight-to-nine-hour time difference, and
they would be a budget buster. S o we decided to conduct the conversations
via E-mail. I wrote a series o f questions on a particular topic, an d Jensen
replied. We had ou r printed transcript proofed, b u t the only oth er modifi­
cations are those requested by the publisher, W estview Press, to remove rep­
etition, to clarify som e o f the m ore technical passages, or to u p d ate infor­
m ation and references to the scientific literature where appropriate.
M any reject Jensenism w ithout examining the evidence because they
fear what m ight follow if it gained widespread public acceptance. I want
you to be able to decide for yo u rself whether Jensenism represents one
m an’s search for provisional, n ot metaphysical, tru th through the continu­
ous and vigorous application o f the methods o f science, that is, by for­
m ulating hypotheses and gathering data against which to test them , or a
dangerous diversion back down a blind alley o f o ld and disproven ideas,
deceptively dressed up in m odern scientific jargon.
T h e Prelude introduces you to “the man b eh in d the ‘ism.’” I t includes
a biographical an d professional sketch o f “Jensen before Jensenism .”
Chapter I, “Jensenism: A N e w Word in the Dictionary,” provides a
perspective on “Jensenism ” and explains how a well-respected an d previ­
IN TR O D U C TIO N
3
ously noncontroversial educational psychologist gave rise to a controversial
word in the dictionary. We discuss how in the late 19 6 0 s Jensen’s research
interest turned fro m the serial position effect (h ow and why it’s easier to
remember the first and last item s in a list than th ose in the m iddle) to the
im portance o f general intelligence, as opposed to specific task learning, in
education and in life; and then to the im portant role o f heredity in intel­
ligence, a subject that previously had been alm ost completely neglected.
Jensen recounts his discussions while in W ashington, D.C., with Daniel
Patrick M oynihan, who was then N ixon’s presidential assistant fo r urban
affairs, and with George H . W. Bush, who was then a R epublican con­
gressm an from Texas. Jensen’s own disdain, n o t for individuals but for
things political as opposed to scientific, is apparent.
In Chapter 2 , “ W hat Is Intelligence? T h e g Factor and Its Rivals,”
Jensen defends the theory o f general intelligence (the g factor) against the
criticism that the g factor is m erely a statistical artifact. W hen I present the
best-known rival theories o f intelligence, Jensen explains why he believes
that the difference between the g factor theory and R obert Sternberg’s
Triarchic T h eo ry o f Analytical, Practical, and Creative Intelligence is a
semantic one, while he sees H oward G ardn er’s T heory o f M ultiple
Intelligences as a form o f psychological biography, but not true science.
T h e chapter concludes with Jensen explaining how state-of-the-art tech­
nologies such as P E T scans provide even more su p p o rt for his conclusions
than just I Q tests.
In Chapter 3, “ Nature, N urture, or Both? Can H eritability Cut
Psychology’s G ord ian Knot?” we discuss the m eaning o f heritability— the
statistic used in quantitative genetics to resolve the nature-nurture ques­
tion— what it can tell us and w hat it can’t. Jensen’s critics often accuse him
o f m isinterpreting heritability. S till others deny that the heritability statis­
tic (as op p o sed to the concept o f heredity) has any meaning in human
research, where controlled experiments are ethically unacceptable. A s evi­
dence for the genetic basis o f intelligence, Jensen describes how closely the
observed correlations between various degrees o f kinship (identical twins,
ordinary siblings, parents and their natural children, parents with their
adopted children) fit with the correlations predicted by the genetic theory,
but go against th ose predicted from a purely cultural theory. In particular,
4
INTELLIGENCE,
RACE,
AND
GENETICS
he draws a com parison between the high correlation o f 0 .8 7 (LOO being
perfect correlation) between the IQ s o f identical twins separated early in
life and reared apart (who share 1 0 0 percent o f their genes, but 0 percent
o f their environment), and the m uch lower correlation o f 0 .3 2 between the
IQ s o f unrelated children reared together (who share 0 percent o f their
genes, but 1 0 0 percent o f their environment). T h e chapter also includes a
discussion o f the Burt A ffair— the controversy surrounding the accusation
that Sir Cyril Burt had “ faked” his twin studies, whose results Jensen had
quoted in his H ER article— and o f Jensen’s involvement in it.
C h ap ter
4,
“ W h at
Is
R ace ?
B iological
R eality
or
C u ltu ral
C onstruction?” examines the biggest taboo o f all— the subject o f race. I
ask Jensen how he, an educational psychologist, can reject the official state­
m ent o f the American A nthropological A ssociation that race is a mere cul­
tural construction and has no biological validity. Jensen counters th at the
m ost state-of-the art population genetic studies and statistical procedures
identify “population clusters” that correspond quite closely to the racial
classifications o f traditional anthropology and even o f “the m an on the
street,” although the term “ race” is avoided.
Jensen then presents three lines o f argument to support what he calls
the D efault H ypothesis— that both genetic and environmental factors play
about the same part in causing the average difference in IQ between Blacks
and W hites as they do in causing differences in I Q within either race. First,
he claims that the attem pts to explain the Black-W hite IQ difference in
term s o f social, economic, or cultural factors alone have been tested and
they have failed. W hen I cite ten o f the best-known theories, Jensen explains
why he believes they have been disproven. H e draws particular attention to
the results o f trans-racial adoption studies, which show that Black children
adopted by W hite middle-class parents end up with IQ s at about the Black
average, while mixed-race adopted children have intermediate IQ s, and
W hite adopted children have IQ s around the W hite average.
Jensen’s second argument, drawn from evolutionary biology, is that
whenever two groups differ in physical characteristics, they will d iffer in
behavior as well. H e cites a fam ous study that dem onstrated that Black,
W hite, and Chinese American babies, all in the sam e hospital and tested
in the first days after birth, differed in movement and activity. N ext, Jensen
IN TRODUCTION
5
claims that both the correlation between brain size and intelligence within
either race, and the average difference in brain size and in intelligence
between Blacks and W hites, are well established in the scientific literature.
Jensens final argument that genes play a role in the Black-W hite I Q
difference is based on what he calls Spearm an s hypothesis. Charles
Spearm an, the fam ous British psychologist who first used the term g (gen ­
eral m ental ability), also remarked that the more a given test m easures the
g factor, the greater the average Black-W hite difference on that test. Jensen
explains that his research has confirm ed Spearm an’s hypothesis for a num ­
ber o f different m ental tests, given in different countries, by different
examiners. Further, he has shown that g is related to a number o f bio lo g i­
cal measures such as brain-wave patterns, glucose m etabolism in the brain,
and well-known genetic phenomena such as inbreeding depression (th at is,
the reduction in height, physical development, and I Q in children bo rn o f
close-relative m arriages).
Chapter 5, “ From Jensenism to T he Bell Curve Wars: Science,
Pseudoscience, and Politics,” draws Jensen out on subjects he has until now
touched on only sparingly, if at all— the questions o f race, science, and
politics in American history, why he believes the race-genetics-IQ question
has been so systematically m isrepresented in the m ass media and in many
textbooks, his analysis o f the m o st vocal o p p o sitio n individuals and
groups, and the role o f the Pioneer Fund (which has supported m uch o f
his own work) in race-IQ research. I ask why, i f he is correct, Jensenism is
so often treated as pseudoscience, and organizations such as the Am erican
Psychological A ssociation (A PA ), the Behavior Genetics A ssociation
(B G A ), and the Educational T esting Service ( E T S ) have either disagreed
with Jensenism (a t least on the issue o f race, genetics, and IQ ) or remained
silent. Jensen cites a survey o f the members o f the Behavior Genetics
A ssociation and the T est and M easurem ent D ivision o f the APA (D ivision
5 ), as well as a statem ent in the Wall Street Journal signed by 5 0 experts in
the behavioral sciences, as evidence that among experts in the relevant dis­
ciplines, Jensenism is considered mainstream science, not pseudoscience.
(See A ppendix B for the Wall Street Journal statem ent.)
T h e final chapter, Chapter 6, “ Science and Policy: W h at’s to Be
D o n e?” invites Jensen onto truly new ground. Fde presents his view o f the
6
IN TELLIG EN CE,
RACE,
AND
GENETICS
proper role o f scientific fact in setting public policy, including Affirm ative
Action in the public and private sectors, especially in the military, govern­
ment bureaucracy, and the educational system . Jensen also speculates on
what the future holds in term s o f policies such as welfare and eugenics.
A ppendix A lists Jensen’s large and ever-growing bibliography. In addi­
tion to the references at the end o f each chapter, readers lookin g for more
inform ation can refer to Jensens bibliography for relevant articles.
A ppendix B reproduces the statem ent that appeared in the Wall Street
Journal by 5 0 behavioral scientists on 2 5 p oin ts the signatories (including
Jensen) considered “ scientifically well-established.”
T h ro u gh o u t this book my aim has been neither to praise Jensen and
Jensenism nor to bury them. Rather, my goals are:
• First, to ask the questions you w ould ask i f you were inter­
viewing Jensen for a print or T V newsmagazine. Each ch ap­
ter opens with an introduction that provides the background
knowledge necessary to understand the topics covered in that
chapter, much like the m aterial talk show hosts get to “ p re p ”
them for interviews.
•
N ext, since m ost o f Jensens prolific ou tpu t has been in tech­
nical book s and journals, to allow Jensen to respond direct­
ly and conversationally to the objections o f his best-known
and severest critics in the academic world.
•
Finally, whether you conclude that Jensenism is scientifical­
ly rock solid, rotten, or somewhere in between, I want you
to m eet Arthur R . Jensen, the man behind the “ ism.”
Further Reading
T h e reference to debunking Jensenism and its “rotten core” is: Gould, S. J. ( 1 9 9 6 ). The
mismeasure of man (Revised and expanded edition). N ew York: N orton . T h e special journal
issue in which 13 experts, including som e critics, h onored Jensen and his work is:
Detterm an, D. K. (E d .), 1998. A king am ong men: A rth ur Jensen. Intelligence, 2 6 (3),
17 5 - 3 18. T h e m ajor books and articles cited here are listed with the corresponding chapters.
PRELUDE
The Man Behind the “Ism”
F
or all the controversy that has raged around Jensenism, the general
public knows relatively little about Jensen him self. Why? First, alm ost
all o f his more than 4 0 0 publications have appeared in technical journals
o r books. W h at’s more, he’s a b o rn introvert. I f you sat next to h im on an
airplane, you’d probably assume he was an auditor or bank examiner rather
than a professor at the University o f California at Berkeley. I f you m et him
during his long tenure on the Berkeley campus, you’d be much m ore likely
to think he taught business or law than psychology.
S o who is A rth ur R. Jensen? D id anything in his past— nature or nur­
ture— play prologue to Jensenism? T h e play on the words “ nature” and
“ nurture” com es from Shakespeare’s The Tempest, bu t the enigma o f hered­
ity versus environment goes back to the ancient G reek philosophers. W hen
they encountered non-Greeks they wondered whether heredity or environ­
m ent (especially clim ate) could account for the differences in appearance
and behavior. Sim ilar observations were made by the ancient civilizations
in Egypt, China, and India. In the age o f science, first anthropology, then
psychology, then sociology has each tried to resolve in its own way the rid­
dle o f human differences. H ow qualified is A rth ur Jensen to sp eak on so
enduring, so difficult, and so em otionally loaded a topic as the connection
between intelligence, race, and genetics?
T h e authoritative Corsini Encyclopedia of Psychology describes him as:
7
8
INTELLIGENCE,
RACE, AND
G ENETICS
One o f the m o st visible educational and differential p sych olo­
gists in the p ast half-century. Jensen is p rofesso r emeritus o f
educational psychology in the Graduate S ch o o l o f Education,
University o f California, Berkeley. D uring the forty years o f his
tenure at Berkeley, he was a prolific researcher in the psychol­
ogy o f hum an learning, individual differences in cognitive abil­
ities, psychom etrics, behavioral genetics, an d m ental chronometry, and his activity has continued since his official retirement in
1994. H is work, published in seven book s and some 4 0 0 a rti­
cles in scientific and professional journals, has placed him
among the m o st frequently cited figures in contem porary p sy ­
chology, and his name has becom e one o f the “ ism s” o f our
language.
JENSEN
BEFORE JEN SEN ISM
A rthur R . Jensen was born in 1 9 2 3 in San D ieg o , California, where his
father owned a lum ber and building-supplies business. H is paternal
grandparents, the Jensens, were im m igrants from Copenhagen, D enm ark.
O n his m other’s side, Jensen’s grandfather was Germ an. H is m aternal
grandm other cam e from a Polish Jew ish family. B o th families disapproved
o f the m arriage across religious lines, and the couple left Berlin and put
down new roots in the San D iego area. Fluent in Polish, his grandm other
was selected to greet the w orld-fam ous pianist Ignacy (Jan) Paderewski
when he came to San Diego. Early on, Jensen noted how the dour
dem eanor o f his D an ish relatives contrasted w ith the fun-loving atm os­
phere o f his m oth er’s side o f the family.
A s a boy, Jensen attended San D iego public schools. H e was a loner
who read voraciously and said little— except when he had a subject to
speak on. T h en he would hold fo rth at the dinner table, enthusiastically
recounting all he h ad read, until his only sibling, a younger sister, would
plead, “ D o we have to listen to another one o f his lectures?” Y oung Jensen
had little interest in team sports; he preferred hiking through the w oods or
swimming. H is hobbies, which he pursued with diligence, were herpetol­
P R E L U DE
9
ogy and classical music. H e collected snakes, which he would trade to the
reptile keeper o f the San D ieg o Z o o to feed the z o o s king cobra, in
exchange for white rats, which Jensen in turn fed his snakes.
Jensen’s first goal in life was to become a clarinetist in a symphony
orchestra, or better yet, a conductor. H is playing was good enough to earn
an audition with Leopold Stokow skis American Youth Symphony, and
Jensen perform ed as second clarinet with the San D iego Symphony for a year
when he was only seventeen. H e soon realized, however, that no m atter how
much or how hard he practiced, he lacked the “ special som ething” required
to make it to the peak o f the m usical world. S o Jensen switched career paths,
entered the University o f California at Berkeley, and majored in psychology.
Jensens interests in herpetology and classical m usic provide clues to the
eventual rise o f Jensenism. H e clearly had an interest in biology. Catching
and keeping snakes and lizards required carefully observing their behavior.
A t 15 he perform ed experiments to determine whether it was temperature
or light that caused the lizards to go underground. (H e found it was tem­
perature.)
Jensen remains passionate about music, th ough he hasn’t perform ed in
years. H e has a massive collection o f recordings an d he and his wife are sea­
son ticket holders for the San Francisco O pera. W hen lecturing in Europe
he makes it a poin t to attend sym phony and opera perform ances. Jensen’s
decision to abandon a m usical career provides a key insight into his view
not only o f h im self but o f the world. Clearly he had the ability to make a
living from m usic. But the fire that burns inside Arthur Jensen, though
invisible from the outside, is to perform at the very highest level he can. As
he states in Chapter I, he has always been interested in people who have
“ made it.” It is not a desire fo r the trappings or rewards o f success that
drives Jensen but the conviction that he’s doin g what he does best. As he
once told me, “ T h e two sm artest things I ever did were to decide to
become a p rofessor because it’s the only thing I can really do at a level I’m
truly satisfied with and to m arry Barb because she does so much th at allows
me to focus on my work and brings so many things into my life I would­
n’t have w ithout her.”
Perhaps because o f his personal experience with music, Jensen has been
keenly aware o f his own and others people’s lim itations, and he is therefore
10
IN TELLIG EN CE,
RACE,
AND
G EN ETIC S
skeptical o f pie-in-the-sky claims th at “ I f you can dream it, you can be it!”
Instead, he has always practiced an d preached a m ethodical approach o f
setting stepwise goals and reevaluating the next step to take as each succes­
sive rung is reached or not.
AN
INTELLECTUAL ODYSSEY
But why psychology? A s we follow the career o f A rthur Jensen and the
story o f Jensenism, we will also trace the intellectual odyssey o f psychol­
ogy in our time. F ro m its beginning, psychology has varied wildly in what,
how, and why it studies. One tradition — exemplified by B. F. Skin n ers
behaviorism — searches for universal laws that describe the behavior o f all
organism s. D ifferences between individuals, species, or groups are treated
as random error, m uch as a chemist allow s for the measurement errors that
com e from using im perfectly calibrated scales. A second tradition, based
more on the biological sciences, sees observed differences as psychology’s
wheat, not its chaff. T h a t tradition tries to explain human differences in
term s o f the best m ix o f hereditary, biological, and cultural causes.
W heth er the focus is on universal law s or individual and group differences,
however, both these traditions are “ reductionist” approaches because they
reduce the dizzying m ultiplicity o f behavior to either universal laws or a
sm all number o f factors.
In contrast, depth psychology and dynamic psychology are more
hum anistic and holistic. They try to solve each individual’s “problem s” by
understanding the totality o f his or her existence. Sigm u n d Freud’s psycho­
analysis is the classic example. T h o se w ho follow the m odel o f the hard sci­
ences reject such m ethods as being literary or mystical, not scientific. But to
many, the methods o f hard science are too cold and detached. T h ey argue
that an obsessive drive for scientific purity produces a sterile psychology,
indifferent to individual suffering and irrelevant to the problems o f society.
T h e se then are psychology’s S cy lla and C h arybdis— a sum m ons for
m ethodological purity that steers research further and further toward
im personal generalization versus a cry for com m iseration that leads into
the m ists o f m ythology, not science. Jensen was drawn to psychology
because he believes that it can produce answers to im portant problem s for
PRELUDE
II
individuals and society. He becam e disenchanted with pure experimental
psychology because he saw it sharpening its focus by excessively narrowing
it. H e wasn’t interested in spending his career determ ining the precise dif­
ference in reaction time in two experimental situations for its own sake.
However, when he wanted to know what differences in a purely objective
measure such as reaction time could reveal about individual and g ro u p dif­
ferences in I Q , he revived and reestablished the field o f mental chronometry, even designing some o f the measuring instrum ents himself.
W hen Jensen turned to clinical psychology, he again becam e disen­
chanted— this tim e because his own studies proved that tests based on the
assum ptions o f depth psychology simply were n o t valid predictors o f any­
thing except how that person answered that test. T h e situation is m uch like
trying to measure people’s m usical or athletic ability by asking them to
name their favorite artists or players. T h e test is reliable. M o st peop le will
have the same personal picks fro m one day to the next. But this tells us
nothing about their own ability.
After graduating from Berkeley in 1945, Jensen returned hom e and
worked at his father’s business, then as a technician in a pharm aceutical lab­
oratory, as a social worker, and as a high school b io lo g y teacher an d orches­
tra conductor while getting a m aster’s degree in psychology fro m San
D iego State University. T hen in 1 9 5 2 Jensen went to Teachers College,
C olum bia University, to study educational and clinical psychology. There
he worked as a laboratory technician in C o lu m b ia’s Z oology D epartm ent
and as a research assistant to his m ajor p ro fesso r and mentor, Percival
Sym onds, an exponent o f dynam ic psychology and projective tests.
Together, they co-authored From Adolescent to Adult ( 19 6 1), based on their
research. Jensen’s doctoral dissertation, “A ggression in Fantasy and Overt
Behavior” ( 1 9 5 6 ) , cast doubt on the scientific ability o f one such test, the
Them atic A pperception Test, to predict individual differences o f aggres­
sion, either in degree or type.
During a year’s clinical internship at the University o f M aryland’s
Psychiatric Institute in Baltim ore (1 9 5 5 —1 9 5 6 ), Jensen becam e further
disillusioned with dynamic psychology. At the sam e time, he was drawn to
quantitative and experimental research on personality by H an s J. Eysenck
at the University o f London’s Institute o f Psychiatry. A postd o cto ral fel-
12
IN TELLIG EN CE,
RACE, AND
GENETICS
Jensen’s first appearance on T V (Channel 2, Oakland) after hefirst wrote on the role of genetics and
I Q in school achievement while a fellow at the Center fo r Advanced Study in the Behavioral Sciences,
Stanford University. (Spring 1967)
low ship from the N ation al Institute o f M ental H ealth (N I M H ) allowed
Jensen to spend 1 9 5 6 —1958 w orking in Eysencks lab.T h ere he thrived, his
passion for research that em phasized both scientific rigor and real-life rel­
evance being shared n ot only by E ysenck but also by others in the L o n d o n
Sch ool o f psychology. T he intellectual origins o f Jensenism lie in the sci­
entific worldview and methods o f the London Sch ool, which was estab­
lished by Sir Francis Galton and C harles Spearm an, the founders o f psy­
chometrics, differential psychology, and behavioral genetics.
Inspired by his work at Eysenck s lab, Jensen returned to the S tates and
was appointed assistant p rofessor o f educational psychology in the
University o f C alifornia at Berkeley in 1958. In 1 9 6 6 he became fu ll pro­
fessor and then research psychologist in the Institute o f H um an Learning
there. Jensen spent his first sabbatical year (1 9 6 4 —1 9 6 5 ) in Eysenck’s lab.
In 1 9 6 6 —1 9 6 7 he was an invited fellow at the C en ter for Advanced Study
in the Behavioral Sciences at Stan ford .
PRELUDE
13
It was only in the late 1 9 6 0 s, after he had established a solid reputa­
tion based on a decade o f careful, noncontroversial research and over 30
publications on hum an learning, that Jensen expanded his focus to include
individual differences in scholastic perform ance am ong culturally disad­
vantaged m inority groups such as M exican Am ericans and Blacks. H e
began by assum ing that any observed group differences were the result o f
socioeconom ic and cultural factors. Increasingly, however, Jensen realized
that the prevailing opinion am ong educational psychologists at that time
just didn’t tell the whole story. H is reading an d research interests turned
more and m ore to biology and genetics.
T hen in 1 9 6 9 the Harvard Educational Review, one o f the m o st presti­
gious journals in the field, asked Jensen to contribute an article to be enti­
tled “H ow M u ch Can We B o o st I Q and S ch ool Achievement?” T h e out­
line HER gave Jensen requested that he include a clear statem ent o f his
position on social class and racial differences in intelligence. Jensen dis­
cussed race and I Q briefly, saying only that while cultural factors were
clearly involved in causing the 15-point difference in average I Q between
Black and W h ite Americans, genes couldn’t be ruled out. As for the arti­
cle’s central question, “ H ow M uch Can W e B o o st I Q and Scholastic
Achievement?” Jensen’s conclusion, based on his review o f the evidence,
could be sum m ed up in two words: N o t much.
Jensen’s H ER article came at a time when “ Black power” was clashing
with the “ W h ite backlash” against Lyndon John son ’s Great Society pro­
gram s. A gainst that backdrop, Jensen rocketed fro m relative anonym ity as
a respected bu t low-profile expert on human learning to blazing notoriety
in the pages o f Time, Newsweek, Life, U.S. News & World Report, and The New York
Times Magazine. H e soon becam e a target o f studen t protests, sit-ins, reso­
lutions o f condem nation, acts o f vandalism, and death threats. T h e word
“Jensenism” entered the R an d o m H ouse and W ebster’s unabridged dic­
tionaries.
D uring his academic career at U C Berkeley, including the 30-plus
years after he becam e “ controversial,” Jensen received every prom otion
possible— even to “ super-grades” beyond the rank o f full professor,
which required recom m endation by a panel o f distinguished internation­
al experts n ot on the Berkeley faculty. Indeed, the closer one gets to expert
14
IN TE LLIG E N CE ,
RACE,
AND
GENETICS
op in ion in the relevant disciplines o f psychom etrics (m ental testin g) and
behavior genetics, the greater the su p p o rt for Jensen and his w ork; and
each year, that su p p o rt increases. O f his m ore than 4 0 0 publications,
none has been in fringe journals, and the overwhelming m ajority have
been in the m o st prestigious peer-reviewed journ als in the relevant
fields— journals such as Intelligence, Behavior Genetics, Personality and Individual
Differences, The Psychological Bulletin, an d Behavioral and Brain Sciences— an d in
such authoritative w orks as The Encyclopedia of Psychology and The Encyclopedia
of Intelligence, where articles are by the editor’s invitation. In 1 9 7 0 Jensen
was a founding m em ber o f the Behavior G enetics A ssociation. H e has
served as a consulting editor to b o th Intelligence and Behavior Genetics, and
publish ed articles in their first issues. Jensen is often asked to serve as a
peer reviewer by these and by m any other academ ic journals because their
c h ie f editors recognize the fairness and thoroughness with which he treats
every article sent to him, regardless o f whether or n ot it agrees w ith his
own position.
In 1 9 9 8 Intelligence published a special issue entitled “A K ing A m on g
M en : Arthur Jensen.” It included Jensens own account o f his career, his
m assive and ever grow ing bibliography, and comm entaries on his life and
w orks by some o f his m ost im portan t admirers and thoughtful, i f g ru d g ­
ing, critics.
M any reject Jensenism not because a careful study o f the evidence has
convinced them that it is scientifically wrong, but because they fear that
racism m ight find scientific su p p o rt i f Jensenism gained general accept­
ance. T h a t is, they reject Jensenism on m oral rather than scientific grounds,
often while attributing political rather than scientific motives to Jensen
him self. However, A rthur Jensen is the least political person I know and
also the m ost straightforward. W h a t you see with Arthur Jensen is what
you get. H e is consum ed by a G andhian dedication to following principle
in m aking decisions, but is willing to reevaluate his decisions based on new
inform ation.
Perhaps that dedication to principle above pragm atism in p art explains
why through all the turm oil and vituperation he has endured, Jensen real­
ly doesn’t hold any grudge against his opponents. Som e, he believes, sim ­
ply h o ld religiously to a different view o f the world, where stubborn facts
PRELUDE
15
have to be subordinated to w hat they believe is the good o f society. Others,
he thinks, just don’t possess the quantitative or analytical sk ills or back­
ground to comprehend the issues objectively. A bout the w orst thing Ive
ever heard him call such individuals, mdeed the harshest w ord I’ve heard
him use, is “ mush-heads.” B ut Jensen is m ost p u t o f f by those w ho say they
agree with his conclusions completely but d o not understand how he
arrived at them. “ I’d rather sit across the table from either o f the first two
groups than the third, som eone who likes w hat he thinks I ’m saying just
because it seems to agree w ith his own prejudices,” he once to ld me. Jensen
has pursued the role heredity plays in the Black-W hite difference in aver­
age I Q not because he is o b sessed with race b u t because he is dedicated to
understanding what he believes is society’s m o st im portant possession —
intelligence. T o dodge the race question w ould be to ignore an im portant
piece in the puzzle— an act o f intellectual cowardice.
O ur conversations on intelligence, race, an d genetics now begin with
my asking Jensen how a once noncontroversial name gave rise to the most
controversial “ ism ” in contem porary behavioral science.
Further Reading
T h e juxtaposition o f “ nature" and “ nurture” comes fro m Shakespeare’s The Tempest (Act
IV, Scene I), where Prospero refers to Caliban as “ a devil, a born devil o n whose nature
nurture can never stick.” Sir Francis G alton , the father o f the study o f h um an differences
in mental ability, picked up what he term ed the Bards “ alliterative antithesis.” (See Galton,
F. [1 8 7 4 , 1 970], English men of science: Their nature and nurture. London: F ran k C ass [1 9 7 0
reprint]; and G alton, F. [1 8 7 5 ], T h e history o f twins, as a criterion o f the relative pow­
ers o f nature and nurture. Fraser’s Magazine, 12, 566—5 7 6 .) In the chapters th at follow, you
will see how m uch Jensen and others in the London S c h o o l o f psychology have followed
in G alton s footsteps.
T h e source o f the brief Jensen biography is: C raigh ead, W. E., and N em ero ff, C. B.
(2 0 0 1 ). The Corsini encyclopedia of psychology. New York: W iley. The special jou rn al issue in
which 13 experts, including som e critics, honored Jensen and his work is: Detterm an, D.
K. (E d .), 1998. A king among m en: A rthur Jensen. Intelligence, 26 (3), 1 7 5 —3 1 8 .
For Jensens own account o f his 1 9 6 9 Harvard Educational Review article, the origin o f
“Jensenism” and the reaction to it, see the 67-page preface to: Jensen, A . R . (1 9 7 2 ).
Genetics and education. N ew York: H a rp e r and Row. T h e other biographical information
com es from my many conversations with Jensen.
I
JENSENISM
A New Word
in the Dictionary
I
n this chapter I ask Jensen to explain how in 1 9 6 9 his nam e became
inextricably linked with the controversial issue o f intelligence, race,
and genetics. A t that time, A m erica was as d eeply divided over race rela­
tion s as it was by the V ietnam W ar. N um erous studies financed by the
federal governm ent and leadin g foundations all docum ented thait the
average I Q o f Black Am ericans ( 8 5 ) was 15 p o in ts below that o f W hites
(1 0 0 ) . A t first, Jensen agreed w ith other edu cato rs and psych ologists—
an d ju st about every other so cial scientist— th at environmental factors
such as lim ited opportun ities, low er average incom e, and the legacy o f
slavery, Jim Crow, and segregation , were the cause. Academ ic research
aim ed at finding the best m eth o d to alleviate the 15-point Black-W h ite
I Q gap came to focus more an d m ore on early intervention to circum vent
environm ental obstacles to cognitive developm ent. H ead S ta r t remains
the best known o f the resultant program s for early cognitive stim ulation
o f the disadvantaged.
O utside o f academ ia, however, many W h ite Americans— an d not
ju st those in the South — h ad becom e disenchanted with th e Great
Society program s. A ided by a p olitical backlash am ong W hites op p o sin g
such program s, R ich ard N ix o n was elected p resid en t on a law -and-order
p latform in 1 9 6 8 .
17
18
INTELLIGENCE,
RACE, AND
GEN ETIC S
In 1969, the respected Harvard Educational Review (HER) comm issioned
Jensen to write an evaluation o f educational intervention program s. The
resulting 123-page article, “H ow M uch Can We B oost IQ and Scholastic
Achievement?” remains one o f the m o st cited works (either vilified or praised,
depending on the reviewers point o f view) in the social science literature.
Based on his review o f the evidence, Jensen reached three conclusions
that were diam etrically opposite to the prevailing view:
•
C om pen satory education h ad been tried, an d it had failed to
raise significantly either the I Q or the sch o o l performance o f
disadvantaged children.
•
Genetic differences were m ore im portant than cultural or
socioeconom ic differences in explaining individual d iffer­
ences in I Q within the W h ite population (th e only group for
which there were adequate data at that tim e).
•
M ost explosively— it was therefore only reasonable to ask
whether genetic differences played some role in the 15-poin t
Black-W hite average-IQ difference.
T h e HER article became a m ajo r media event. Its three m ain points,
dubbed “Jensenism,” entered our vocabulary. Jensen became the target o f
studen t protests, sit-ins, acts o f violence, and even death threats. A cadem ic
criticism came in the form o f resolutions from scholars and professional
organizations condem ning Jensenism . In M ay 1 9 6 9 , in a three-hour sym ­
posiu m held for security’s sake in a closed studio on the Berkeley cam pus
(b u t broadcast to an outside audience), Jensen defended Jensenism before
a panel o f questioners who were am ong the m o st distinguished figures in
their respective disciplines. T h ey were geneticists Jo sh u a Lederberg ( 1 9 5 8
N o b e l laureate in Physiology or M edicine) and W illiam J. Libby; mental
testing expert Lee J. Cronbach; A rth ur Stinchom be o f the U C Berkeley
S o cio lo g y D epartm en t; and A aron Cicourel o f U C Santa Barbara, an
authority in the field o f psycholinguistics. T h e distinguished geneticist
C u rt Stern acted as m oderator. Obviously, the sym posium failed to resolve
the issue, but it show ed that Jensen could go toe-to-toe with em inent crit­
ics and give at least as good as he got.
JEN SEN ISM
19
Jensen also gives us his firsthand observations and im pressions o f
im portan t people in science, m usic, and politics. T h ro u g h Jensens eyes we
m eet C olum bia University p ro fesso rs H enry E . G arrett and O tto
Klineberg, who op p o sed each other vigorously in an earlier debate on race
and IQ ; anthropologist M argaret M ead, who w ould later lead a protest
against Jensens election as a fellow o f the Psychology Section o f the
Am erican A ssociation for the Advancement o f Science (A A A S) after his
HER article appeared; Sir Cyril Burt, who years later, after his death, w ould
be accused o f faking his fam ous study o f identical twins reared apart,
which Jensen cited in the HER article (see Chapter 3 for a discussion o f the
Burt A ffair and Jensens involvement in it); George H . W. Bush, then a Texas
congressm an; D aniel Patrick M oynihan, whose report to President N ix o n
on the Black family produced a race controversy o f its own; and conductor
A rturo Toscanini, whose concerts and rehearsals Jensen attended regularly
while a graduate student at C olum bia. Jensen reserves his greatest praise for
his mentor, the late British psychologist H ans J. Eysenck, for having shaped
fundam entally his attitudes about psychology and science.
M iele: Back in 1 9 6 9 you were an educational psychologist in the
G raduate Sch ool o f Education and a research psychologist in the
Institute o f H u m an Learning at the University o f California in
Berkeley. Your work was well respected and you had no history o f
enjoying or even seeking controversy. I f anything, the opposite was
the case— you were best known for researching things like the serial
position effect in learning.
T h e n your article “ H ow M u ch Can We B o o st I Q and Sch olastic
Achievement?” appeared in the W inter 1969 issue o f the Harvard
Educational Review. M o st HER articles are read by professionals and
graduate students in educational psychology and attract little ou tside
notice. But yours produced a national controversy that was covered in
the m ajor news magazines as well as on T V and radio. It generated
heated discussion in professional journals, resolutions condem ning
you and the article, student protests, sit-ins, acts o f violence, and even
death threats. Eventually, the w ord “Jensenism” even entered the dic­
tionary.
20
INTELLIGENCE,
RACE, A N D
GENETICS
W h at d id you say in th at lengthy, 1 2 3 -p ag e HER article that
hadn’t been said before? A fte r all, y o u d given a talk with the same
title two years earlier.
Jensen: T h ree things about the HER article com bined synergistically
to set o f f all the com m otion. Each o f them was quite contrary to the
prevailing Zeitgeist.
First, I examined the available research an d concluded that com ­
pensatory educational program s had failed to show any strong or
lasting effect in raising I Q or scholastic achievement. Second, I
reviewed the existing evidence showing that genetic factors played a
large p art in individual differences in IQ. A n d third, I said the total­
ity o f evidence was m ost consistent with the hypothesis that genetic as
well as environmental factors are involved in the average difference
between Blacks and W h ites in IQ and scholastic achievement.
Although it was less than 5 percent o f the whole article, this small
part— hypothesizing a genetic com ponent in the racial I Q differ­
ence— produ ced the m ost vehement vituperation.
T h e 1 5 -p o in t difference in average IQ between Blacks and W hites
in the U n ited States had been well established by the psychological
research. But never before (including in the talk you just m entioned)
had I suggested the plausible hypothesis that b o th environment and genes
were involved. T h is hypothesis was plausible because research h ad not
found any com pelling explanation for all o f the 15-point difference,
and because genetic factors as well as environmental factors were
responsible fo r individual differences in I Q w ithin either racial group.
Miele: But claim s about racial differences in bram size in fact go all
the way back to Paul Broca, discoverer o f one o f the im portant
speech centers in the brain. A nd there was R obert Bennett Bean’s
study o f Black-W hite differences in brain size, which was cited by
H enry G arrett and others, such as W. C. G eorge in his pam phlet The
Biolog)/ of the Race Problem, issued by the G overnor o f Alabam a (G eorge
Wallace’s predecessor, John Patterson). T h e mainstream trend in
J E N S E N IS M
21
anthropology and psych ology was to debunk those studies. Were you
aware o f all this?
Jensen: I'm chagrined to say that at the tim e I wrote m y H ER paper I
wasn’t. A year or two later someone sent m e a copy o f G eorges pam­
phlet. A s he was a professor o f anatomy, I thought it m igh t be worth
reading. A t that time I was on a committee chaired by the late Professor
H arry Harlow, the fam ous researcher on primate behavior. Harlow was
quite knowledgeable ab o u t brain research, physiological psychology,
and the like. I gave him a copy o f George’s essay and asked for his opin­
ion. H arlow believed that genetics played a part in racial differences and
that there are racial differences in brain size. But he was unimpressed by
Georges evidence. H e thought it was antiquated and questionable and
said he w ould put very little stock in it. S o I ignored it.
T h e study by Bean doesn’t ring a bell. I can’t recall having come
across it in my fairly extensive review o f studies on brain correlates o f
intelligence. But i f it’s a reputable piece o f research, I sh o u ld have it
in my files. T he fact th at it was cited in an essay issued by the
G overnor o f Alabam a back around the time o f federally enforced
school desegregation in the South sh o u ld lead one to exam ine it care­
fully to see i f it actually has any scientific merit.
A fter the publicity surrounding m y H ER article, I d id receive a
num ber o f letters from so-called citizens’ groups in various Southern
states, asking if I w ould write letters to their local new spapers in sup­
p o rt o f racial segregation in public schools. I replied th at I was, and
always have been, absolutely op p o sed to racial segregation o f any
kind. O n e o f these people wrote b ack calling m e “ ju st another
Berkeley pinko!” H e at least gave me the satisfaction o f knowing that
I had angered him.
M iele: W ell, Sir Cyril B u rt had already m ade the case fo r genetic fac­
tors in I Q and scholastic ability in a num ber o f papers, including his
fam ous 1 9 5 7 Bingham Award Lecture sponsored by the American
Psych ological A sso c ia tio n titled
“ T h e Inheritance o f M ental
22
IN TE LL IG E N C E ,
RACE,
AND
GENETICS
Ability.” S o did a 1 9 6 3 review article by N ikki Erlenmeyer-Kimling
and L issy Jarvik in Science.
Jensen: I had heard o f Burt as one o f the preeminent figures in psy­
chology since I was an undergraduate student in Berkeley. And so I
attended his Bingham Award Lecture during the seco n d year o f my
postdoctorate at L o n d o n University, though I had no special interest
in the topic at that time. I went sim ply because I w anted to see
Britain’s m ost fam ous psychologist in person. H e was then 75 years
old, and I thought I m igh t never get another chance to see the great
man. Little did I im agine then that ab o u t 13 years later I would get
to know him quite well personally and eventually becom e involved in
the Burt Affair. [See C hapter 3 for a discussion o f the Burt Affair
and Jensens involvement in it.]
M iele: D id he live up to your expectations?
Jensen: H is Bingham Lecture was the best lecture I h ad ever attend­
ed. Burt spoke entirely without a scrip t and had the kin d o f elo­
quence, showmanship, and authority that really held his audience
spellbound. A brilliant and impressive man.
M iele: T h e third and m o st controversial p art o f your H E R article, the
genetic role in racial differences in I Q , had been m ade by Audrey
Shuey in the two edition s o f her lengthy 1966 b o o k , The Testing of
Negro Intelligence, which you cite in the H ER article. A nd H e n ry Garrett,
a p ast president o f the American Psychological A ssociation, had been
carrying on a running debate with O tto Klineberg and others on the
subject (though you d o n ot cite those).
S o was it really your novel com bination o f the them es that gar­
nered all the headlines? O r was it the fact that you cam e to the raceI Q debate with clean hands, so to speak, because you were a respected
researcher in com pensatory education who had never supported—
and who, indeed, o p p o se d — attem pts to overturn the Brown v. Board
school desegregation decision?
JEN SEN ISM
23
Jensen: W h at you’ve said is true, but I’d like to qualify it a bit.
By 1 9 6 9 , Shuey’s b o o k and G arretts writings, if n o t Klineberg’s,
were far in the background. Shuey got her Ph.D. under Garrett at
Colum bia University. T h e y both wrote as i f the fact th at hundreds
o f studies consistently fo u n d a mean Black-W hite difference o f
about 15 I Q points con stituted sufficient evidence that the difference
was largely, i f not entirely, genetic. O f course it is not sufficient evi­
dence. N eith er Shuey n or G arrett attem pted to examine the issue in
a way that could lead to any conclusion. T h a t requires investigating a
whole network o f relationships and different lines o f em pirical evi­
dence. A hundred or a thousand times as many IQ test com parisons
as the three hundred or so that were com piled by Shuey could not
have brought us any closer to understanding the causes o f the BlackW hite I Q difference.
Miele: T h en why did you cite Shuey’s work, i f not G arrett’s?
Jensen: Because when I viewed the purely psychometric evidence pre­
sented by Shuey in relation to the fact that genetic and environmen­
tal factors play a p art in individual variation in intelligence within
either race, along with a num ber o f other facts, I thought it was sci­
entifically necessary to investigate the p ossibility o f genetic as well as
environmental factors in explaining the Black-W hite average-IQ dif­
ference.
M iele: Since you were all at Colum bia University, did you ever meet
Garrett, Shuey, or Klineberg? I f so, w hat were your im pressions o f
them?
Jensen: I m et both G arrett and Klineberg when I was a g rad student
there. I even audited Klineberg’s course on social psychology, not
because I was interested at that time in any o f these to p ics we’re now
discussing, but sim ply because he was one o f the fam ous names in
psychology. For the sam e reason, I audited an anthropology course
given by M argaret M ead , and I became acquainted with the venera­
24
INTELLIGENCE,
RACE,
AND
GENETICS
ble dean o f experim ental psychology, R obert S. W oodw orth, whose
classic textbook I h ad used as an undergraduate psychology student
at Berkeley. I was always interested in what people w ho had “m ade
it” were like in person.
M iele: A nd Garrett?
Jensen: Yes. I wanted to take a course in factor analysis given by
P rofessor Helen M . W alker. She was a noted statistician and one o f
the tw o or three best professors I ever had. U nfortunately she was on
sabbatical that year. Sin ce Garrett o ffered a less specialized course, I
went to him to find o u t just what it covered. H e asked about my pre­
vious courses in statistics and suggested I audit just the couple o f lec­
tures on factor analysis. T h ey were very introductory and covered less
than I had already p icked up from the chapter on facto r analysis in J.
Paul G uilford’s fam ous textbook Psychometric Methods.
I fo u n d Garrett a rather lackadaisical and perfun ctory lecturer,
and I was glad that I hadn't enrolled fo r his full course. H e seemed
friendly, but was quite im personal and m atter-of-fact. N oth in g
about him left me w ith any clear p erson al impression. In this respect,
he was a rather typical professor.
Klineberg was a very precise and professorial fellow, short and
com pact, with very close-cropped gray hair. He was a g o o d lecturer,
though n ot very anim ated; he usually sa t at a desk while lecturing but
he nearly always h ad
considerable enthusiasm fo r his subject.
Personally, he was quite form al but very cordial and courtly, much as
I later found to be m ore common am o n g the older European profes­
sors. S ir Cyril Burt, fo r example, had a sim ilar personal style.
M iele: W hile we’re strolling down m em ory lane, what were your
im pressions o f M ead an d W oodworth?
Jensen: M argaret M e a d was truly an unforgettable character. I never
met her personally, b u t audited her lectures at C olum bia. She always
came across as a w om an o f great energy, with boundless enthusiasm
JEN SEN ISM
25
for whatever she was talking about. H e r lectures were im m ensely col­
orful an d entertaining. A n d it was clear th at she thoroughly enjoyed
her showmanship. I still vividly remember som e o f her anecdotes and
descriptions, such as her telling, com plete with hilarious arm-waving
gestures— about the sw inging pendulous breasts o f the older Sam oan
women. It brought the house down. She was usually quite “ earthy,”
and never high-flown. A s an entertaining lecturer, few college profes­
sors could compete with her.
I fo u n d many o f her statements involving psychological matters
highly provocative because they so com pletely contradicted what I
had learned from other professors at Colum bia. For example, she
thought schizophrenia was a cultural condition, defined as a disease
only in m odern W estern cultures. I m entioned this to Jo seph Zubm ,
who, in his course on abnorm al psychology, taught that schizophre­
nia is a genetic brain disorder. H e was m o st annoyed th at M argaret
M ead was teaching “ such blatant nonsense” to so many students. M y
m ajor professor, Percival Sym onds, was greatly amused when I told
him I was auditing M e a d ’s course. H e said something like, “I hope
you’re n ot taking it seriously, because when it comes to psychology
she doesn’t know what she’s talking about.”
R o b e rt W oodw orth was an im pressive m an and a m o st interest­
ing lecturer. H e personally knew every b ig name in the history o f
A m erican and European psychology, fro m W illiam Jam es on. T h is
wealth o f personal, an ecd otal knowledge, com bined w ith his fan­
tastic scholarly erudition, m ade his course on history an d systems
o f psych ology a m em orable experience. It was also an inspiration to
see som eon e in his late 8 0 s who was so physically fit an d mentally
sharp.
T h e first time I m et W oodw orth personally, I to o k alo n g one o f
his b o o k s fo r him to autograph, w hich he did. I ask ed him some
q uestion s about E. L . T h o rn d ik e, co -au th o r o f his fam o u s study
on the “ transfer o f training.” I w an ted to get W ood w o rth ’s per­
sonal im pression s o f T h o rn d ik e the m an. But he rather dism issed
my q u estion , saying he would be d iscu ssin g T h o rn d ik e in his
course.
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T h en to my surprise, W oodw orth proceeded to m ore or less inter­
view me, saying, “ Well, you already know about me. I ’d like to know
som ething about you.” H e asked m e about the other courses I was
taking, which p rofessors I had— he knew them all and commented
knowingly about each one. Then he asked me a m ost interesting ques­
tion to which I wasn’t prepared to give a very g o o d answer: “ W hat
d o you want to be doin g ten years fro m now? T h a t’s the way to think
abo u t what you’re doing now.” I frequently recall W oodw orth’s good
influence on me.
M iele: You said, “ I was always interested in what people who had
m ade it were like in person.” W h o were the m ost impressive people
yo u ’ve met? W h at d id they have in com m on?
Jensen: I have already m entioned my m ajor professor, Percival
Sym onds. I learned som ething abo u t g o o d work habits from him. H e
was also the first person who ever to o k the trouble to offer quite
detailed criticisms o f things I wrote. H e emphasized that i f I was ever
to becom e what he called “a real professor,” it was essential that I
“ research and publish.” Sym onds h im se lf was a prolific and clear
writer, and he knew all the ropes for getting published. T hough he
never tried to indoctrinate me in his own beliefs, he did want me to
develop the habit o f writing. I liked this and profited greatly from his
mentoring.
By far the m ost im portant person in my career, o f course, was
H a n s Eysenck. I spent two years w ith him as a p o std o c and another
year on my first sabbatical leave fro m Berkeley. From his writings, I
h ad great expectations o f Eysenck when I went to England to work
in his department, and they were m ore than fulfilled. Eysenck was a
k in d o f genius, or at least a person o f very unusual talents, and the
only person o f that unusual caliber that I have com e across in the
field o f psychology. I have known a num ber o f very capable and truly
outstanding persons in psychology, and persons whose scientific con­
tributions are on a par with, or m ay even exceed, Eysenck’s, but none
who were what I w ould think o f as som e kind o f phenomenon.
JE N SE N IS M
27
I g o t perhaps as m uch as 9 0 percent o f my attitudes about psy­
chology and science from Eysenck. T h e three years I spent in his
departm ent have been a lasting source o f inspiration. I dread to think
where my own career m ight have gone had I never m ade the Eysenck
connection. I think Eysenck was a great man and have written in
detail about my im pressions o f him.
M iele: W hat about peop le outside o f psychology?
Jensen: I’ve never really gotten to know any politicians personally. Once
after testifying in Congress I m et form er president George H . W.
Bush— at that time a congressman fro m Texas— and chatted with him
for a few minutes. H e knew something about my 1 9 6 9 HER article but
seemed more interested in my personal background— where I was
born, where I grew up, where I went to college, things like that. H e
acted rather amazed by my answers, especially the fact that up to that
time I had never set fo o t in the D eep South. W hen he said, “Isn’t that
interesting, you’ve never been in the South?” I assum ed he was testing
my credentials for m y discussing the nature o f the Black-W hite differ­
ence in IQ. But that top ic never came up in our b rief conversation.
T h e one really great politician that I observed at close hand was
Jawaharlal Nehru, the then prime m inister o f India. I had read N ehru’s
autobiography Toward Freedom and his The Discovery of India, both beauti­
fully written books, so I enjoyed the opportunity o f seeing him in per­
son. S o many people were in line to shake hands with him that I got out
o f the line and went u p to where I could observe him up close for longer
than i f I had remained in line and waited my turn to shake hands. H e
was shorter than I h ad imagined (five feet, six and a h a lf inches, to be
exact), but he was surprisingly handsome. Even at age 65, N ehru had a
dynamic and charismatic quality, fitting for a prime minister.
M iele: A nd Gandhi? Briefly.
Jensen: I ’ll try to be brief. M ahatm a G andhi has been m y number one
hero since I was 1 4 years old. I never saw him in person, o f course,
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but up until perhaps 2 0 years ago I thought I had read everything
written about him in English, certainly m ore than I have ever read on
any other person or subject. Then, in 1980, when I visited the
G andhi Library at the Punjab University in Chandigarh, India, I dis­
covered that I had read only a fraction o f the nearly 5 0 0 book s and
several thousand articles then written abo u t Gandhi, n ot to mention
the handsom e 90-volum e set o f his own writings publish ed by the
Indian government.
M iele: W hy Gandhi? H e wasn’t a scientist.
Jensen: T h e greatest thing about G andhi was his truly great and mov­
ing life. W hen a new spaper reporter asked him, “W h at is your mes­
sage?” Gandhi replied, “ M y life is my message.” A nd an absolutely
extraordinary life it was! O ne o f those rare individuals who, as they
say, is larger than life. H e was also one o f the few people I know o f
who lived nearly his whole adult life by principle, entirely by princi­
ple. A nd they were difficu lt principles to live up to. Even to have
m ade the attem pt and to have succeeded to the extent th at Gandhi
d id is, I think, awesome. A s Life m agazine wrote, one has to go back
in history to the B uddha and Jesus for com parisons. G a n d h is great­
ness far overshadowed his personal idiosyncrasies and eccentricities.
O ne wonders how m any people could possibly follow Gandhi’s
example. Yet, properly studied, his well-documented life can be a con­
tinual source o f exam ple and inspiration. H e is the one who first
comes to m ind whenever I feel puzzled as to the right course o f
action.
M iele: And in your other love, the w orld o f music?
Jensen: T h e one who im pressed me the m o st was the great maestro
A rturo Toscanini. D u rin g my three years in N ew York I rarely missed
one o f the concerts he conducted with the N B C Sym phony. I even
attended his rehearsals. Toscanini, too, was a charismatic figure, emit­
ting electricity, and perform ing m agic with his orchestra. H is
JE N SEN ISM
29
rehearsals were rather terrifying, even when several rows back from
the stage and not directly in the line o f fire as were the musicians in
the orchestra. Sparks flew. T hey had to becom e inured to his sudden
explosions o f temper. T h ere must have been some very g oo d m usi­
cians who could not play under him.
I last saw Toscanini in rehearsal when he was 87. W h a t seemed so
interesting was the phenom enal passion and the extreme care he had
for the quality o f the performance. I have never seen such a high
degree o f concentration and effort brough t to any task by anyone
else. A t tim es his trem endous concentration and m ental energy struck
me as abnorm al and a b it frightening— like the sun being brought to
a w hite-hot focus by a great m agnifying glass. It’s clear why all other
conductors, famous and obscure alike, were in awe o f him. O n the
podium he was an elemental force o f nature.
M iele: A n d what qualities did all these exceptional people have in
com m on?
Jensen: T h ree things: A n exceptional level o f ability or talent, unstint­
ing energy, and an intensely concentrated, sustained interest in what
they were doing.
M iele: C ouldn ’t your interest in “ p e o p le who had m ade it” reflect
a certain underlying elitism on the one hand and alm o st clinical
coldn ess towards th ose who haven’t on the other? C o u ld that have
affected your whole approach to the question o f I Q , genetics, and
race?
Jensen: A colleague who knew me quite well once accused me o f hav­
ing an unusual interest in people who were in some way exceptional.
I can’t deny that; but what I will deny is the implied corollary o f what
you call elitism, som e “ clinical coldness,” towards people who aren’t
known for any conspicuous achievement.
I d o believe that the factors that cause some individuals to be
exceptional are largely genetic. O f course, they also need opportuni-
30
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ties and environments that favor the expression or development o f
their exceptional traits. I believe that people o f really exceptional
achievement are exam ples o f emergenesis— a term in behavioral genet­
ics, It m eans that exceptional achievement depends u p o n a particular,
rare com bination o f genetic traits that act multiplicatively, not addi­
tively. I f any one o f the traits is lacking, the exceptional achievement
will n ot occur.
A ccording to Sir Francis Galton, the three traits th at are essential
for outstanding achievement are a high level o f ability, drive or zeal,
and persistence o f effort. Real genius also requires creativity.
M iele: L e t’s get back to Jensenism. In the 67-page preface to your
1 9 7 2 book, Genetics and Education, and in other places, you describe
how this controversy ju st “burst around y o u ” and how you’ve acted as
a scholar just going where the evidence to o k you. Som e critics say you
deliberately courted controversy as a p ath toward advancement. In
that preface you describe how you gave your m anuscript to a reporter
for U.S. News & World Report, a conservative news m agazine, especially
at that time, which had in 1965 run a controversial article along sim ­
ilar lines by W illiam Shockley, “ Is the Q u ality o f the U .S. Population
D eclining?”
S o weren’t you lookin g for a chance to get into the fray in those
tum ultuous times?
Jensen: N o t at all, but I don’t think it w ould be in the least repre­
hensible i f that were the case. I did think that the issues dealt with in
my H ER article were very important. A n d I suppose I m ust accept my
late colleague Lee C ronbach’s claim th at I had a certain “ missionary
zeal,” and I wanted to get my message out. All true. But I wasn’t seek­
ing the com m otion that ensued, nor d id I do anything to prom ote it.
It was unfortunate, but as I view it all in retrospect, I think it was nec­
essary i f discussion o f the issues was to be brought into the open.
M iele: Then how did your m anuscript get into the hands o f the
reporter from U.S. News & World Report?
JENSENISM
31
Jensen with a graduate assistant at the University of California, Berkeley, about the time of the
publication of his H E R article in 1969, which led to the term Jensenism becoming part of our
vocabulary.
Jensen: It was a curious happenstance. T h e reporter was on the
Berkeley campus to cover the student unrest going on at that time. H e
came to my office to get my opinion. I don’t know why he picked me,
because I wasn’t very interested in the matter. I h ad been away in
E u rope during the height o f the so-called Free Speech Movement
that seemed to dom inate the Berkeley campus at th at time.
I to ld the reporter I was involved with som ething I thought far
m ore im portant an d was about to have an article on it come out in
the Harvard Educational Review. H e seem ed interested so I told him the
gist o f the article. H e asked for a copy o f my 2 0 0 -p a g e typescript,
which I gave to him . H e followed up with the editors o f the HER.
T h e y sent him copies o f the seven commentaries on my article they
h ad solicited and said they intended to hold a press conference about
it. W ithin a week o r so, the article was published an d the controver­
sy was reported in U.S. News & World Report, the New York Times, Time, Life,
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INTELLIGENCE,
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AND
GENETICS
Newsweek, and other places. Som e accounts were superficial or inaccu­
rate. O nly U.S. News fir World Report an d Fortune, both o f which have
interviewed me from tim e to time over the years, have consistently
taken pains to check everything with m e for factual and technical
accuracy before going to press.
Miele: But why did you ju m p into the race-IQ issue at that time?
Jensen: Because educational psychologists were trying to discover and
to am eliorate the conditions that caused the large average shortfall in
Blacks’ scholastic perform ance. T hey were investigating a host o f
supposed environmental causes and hypothesizing others. In the
19 6 0 s it was quite tab oo to mention genetic factors in connection
with I Q differences, except perhaps only to completely dism iss them
even as a possibility. But I could find no scientific basis fo r dism iss­
ing the plausibility o f a genetic hypothesis, which o f course always
allows for environmental influences as well. So I th ought it was
im portant to put it on the table along with all the social-cultural-psy­
chological hypotheses being investigated. Moreover, there was already
sufficient evidence to disconfirm som e o f these hypotheses.
I still feel confident that I was right in what I did in 1 9 6 9 . And if
you read my HER article carefully, you’ll see that I stated a hypothesis.
I made no claims that weren’t at least as justified scientifically as any o f
the purely environmental hypotheses that were so popular at that time.
Miele: S o that’s all there is to the origin o f Jensenism? T h e re ’s no
“rest o f the story” ?
Jensen: I f you are looking for some deeper or hidden m otive on my
part, I’m afraid I can't be o f much help. I f anything, my attitudes are
based on a rather lifelong antipathy to believing anything w ithout evi­
dence. A s a kid I was m ore or less kicked out o f Su n d ay school
because o f my argumentativeness and resistance to accepting things
on faith. Scientific ways o f thinking ab o u t things, however, have
always appealed to me, and I feel no, need to believe m uch o f any­
JENSENISM
33
thing. B elief is really irrelevant to science. Its truth status doesn’t con­
sist o f b e lie f and doesn’t depend on belief.
Any certitude I enjoy in my life is based on what could be called
aesthetic experiences, particularly music, and also nature. T h e things
I know and like at this direct sensory and subjective level are good
and right, for me, w ithout need o f any evidence or argument beyond
the experience itself. But I don’t confuse them with the understand­
ing o f objective reality, which, in my opinion, should lie entirely with­
in the purview o f science.
Miele: Even in science, things don’t happen in a vacuum. L e t’s recall
what A m erica was like back in 1969. R ich ard N ixon had ju st been
elected president in a close election, helped by Governor George
Wallace o f Alabama, w hose candidacy h ad been supported by a
W hite backlash against program s o f racial equalization. N ix o n him ­
self benefited directly fro m a demand for law and order and a feeling
among the W hite m ajority that Lyndon Johnson’s Great Society had
been a failure or even counterproductive.
D id you have any involvement or even interest in the Civil R igh ts
M ovement, school desegregation, or the hope that intervention pro­
grams like H ead Start could bo ost the academ ic achievement and IQ
o f disadvantaged children that motivated so many o f your colleagues
in the social sciences at that time? H adn’t you been the beneficiary o f
Great Society research grants?
Jensen: In fact, I voted fo r Johnson in the 1 9 6 4 presidential election.
I felt strongly enough ab o u t it that I voted by absentee ballot because
I was in Lon don on a sabbatical leave w orking as a G uggenheim
Fellow in Eysenck’s departm ent.
I believed in the G reat Society proposals, particularly with respect
to education and H ead Start. W hen I returned to California I gave
talks at schools, P T A m eetings, and conferences and conventions
explaining why these things were im portant and should be prom oted.
I have always been o p p o sed to racial segregation and discrimination.
They go against everything in my personal philosophy, which includes
34
IN TE LLIG E N C E ,
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G EN ETIC S
maximizing individual liberties and regarding every individual in term s
o f his or her own characteristics rather than the person s racial or eth­
nic background. H o w could I think otherwise when at that time I had
been steeped in G andhian philosophy for over 2 0 years?
A nd yes, I d id apply for and receive research grants and contracts
fro m government agencies such as the Office o f Education, N atio n al
Science Foundation, Office o f Econ om ic O pportunity, and N atio n al
Institute o f M en tal Health fo r research on individual differences in
learning abilities and its possible applications to the education o f
p upils who at th at time were called the “ culturally disadvantaged.” I
m et many o f the prom inent leaders in this effort, and attended m eet­
ings in the n atio n s capital. A t th at time I was quite enthusiastic about
its promise. I considered it a socially valuable enterprise for educa­
tion al psychology research.
M iele: Well, one o f those colleagues, M artin D eutsch, with w hom
you had edited a b o o k on the culturally disadvantaged, claimed your
H ER article con tain ed a trem endous number o f errors and m isstate­
m ents. H is exact words were, “ Perhaps so large a number o f errors
w ould not be rem arkable were it n ot for the fact that Jensens previ­
o u s work contained so few, and m ore malignant, all errors referred to
are in the same direction: m axim izing differences between Blacks and
W h ites and m axim izing the possibility that such differences are
attributable to hereditary factors.” Others accused you o f doctoring
figures taken fro m well-known articles just to bolster your case.
T h irty years have passed since your HER article: Is there anything in
it you were forced to correct or that you w ould like to correct now,
o r clarify in the lig h t o f additional information?
Jensen: I did edit a book with M artin D eutsch and Irwin K atz, in
1 9 6 8 . Later, D eutsch , a professor at N ew York University, had reck­
lessly claimed in a lecture at M ichigan State University that there
were 53 errors in m y HER article, “ all o f them unidim ensional and
all o f them anti-Black.” I was shocked by such an outlandish accusa­
tion, and I wrote to him asking fo r a list o f these purported errors,
JE N SEN ISM
35
so I could correct th em in subsequent printings o f the article, which,
incidentally, is still bein g reprinted an d sold by Harvard. Two or three
requests from me failed to elicit a reply from Deutsch. I urged him to
publish any and all errors he claimed to find, but nothing o f the kind
was ever published.
Considering how hard some peop le were trying to pu t down this
article, I was amazed at how little they could actually find wrong with
it! A geneticist friend d id inform m e o f one quite obscure technical
error that only a very sharp-eyed expert would have caught, but it
w ould take longer to explain than it’s w orth in this context. T h e idea
that I h ad “ doctored” figures or d id anything at all like that to make
a poin t is scurrilous nonsense, the last resort o f a fru strated critic.
M iele: T h e other criticism I’ve heard is that you h ad your finger in
the political wind. W h en the N ix o n adm inistration came in you
decided to provide them with the scientific am m unition they needed
to ju stify slashing all o f those G reat Society program s. Any com ­
ment?
Jensen: Absolutely false! T h at way o f thinking is com pletely foreign
to me. I am almost em barrassed by m y lack o f interest in politics and
I was even less interested in those days than I am now. T h e idea o f
providing any kind o f “ ammunition,” scientific or otherwise, to help
any political regime prom ote its political agenda is anathem a in my
philosophy. One always hopes, o f course, that politicians will pay
attention to scientific findings and take them into consideration in
form ulating public policy. But I absolutely condem n the idea o f
doing science for any political reasons.
I have only contem pt for people who let their p olitics or religion
influence their science. A nd I rather dread the approval o f people
who agree with me only for political reasons. People som etim es ask
me how I have w ithstood the o p p o sitio n and vilification and dem on­
strations over the years. T h at hasn’t worried me h a lf as much as the
thought that there m ay be people o u t there who agree with some o f
my findings and views for entirely the wrong reasons— political rea­
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sons, prejudice, ignorance, whatever. It is never the b o tto m line that
I consider im portant, but the route by which one reaches it. T h e only
route o f interest to me is that o f science and reason. I have no use for
political or religious thinking when it com es to trying to understand
real phenomena.
M iele: For the record, then, who first coined the term “Jensenism ” ?
W as it you? Science writer Lee E dson in his article in The New York
Times Magazine? Your arch-critic Leon Kam in? Wasn’t it in fact Daniel
Patrick M oynihan, then adviser on dom estic affairs to Richard
N ixon , and later D em ocratic senior senator from N ew York (now
retired)?
Jensen: It has been my understanding that this term first appeared in
the Wall Street Journal, which was quoting M oynihan. H e m ade a state­
m ent in an interview that went som ething like “ T h e winds o f
Jensenism are blowing through the nation’s capital with gale force.”
O ther m edia then began using the term. It is also in Lee E d so n ’s New
York Times article, which was one o f the few balanced and accurate
reports at that time.
M iele: M oynihan h ad already gotten into som e controversy over his
remarks about the Black family and “ benign neglect.” A nd John
Ehrlichman claims N ix on said som e very “Jensenist” things about
H e ad Start. I f you weren’t interested in the policies o f the Nixon
adm inistration, it certainly sounds as i f they were interested in your
article. W hat was your involvement with M oynihan back when he
was a N ixon advisor?
Jensen: O ne day when I was in W ashington to attend a council meet­
ing o f the A E R A [American Educational Research Association], I
received a message from Moynihan’s secretary asking i f I could come to
his office while I was in town. S o I m et him in the W hite H ouse at
about 4 :0 0 that afternoon. H e was a very open and cordial fellow,
quite jolly and immediately likable. H e offered me a drink from the bar
JE N SEN ISM
37
in his office and asked if I m inded i f he invited his “ assistant on
Jensenism ” to come over from the O ld Executive O ffice Building across
the street and sit in on our conversation. H e buzzed his secretary to call
this assistant, explaining to me that one o f this young fellows assign­
ments was to read m y s tu ff and keep him [Moynihan] informed about
it. M oynihan in turn forwarded this information to President N ixon,
who was keenly interested in Jensenism. We talked abo u t many things
during the hour or so that I was there, including Moynihan’s then
forthcom ing trip to India as ambassador. I had noticed Erik Eriksons
biography o f Gandhi on his desk, an d o f course I couldn’t resist get­
ting into a conversation about that, since I was an aficionado o f the
Gandhi literature an d had met E n k so n , the famous psychoanalyst, at
the very time he was writing his b o o k on Gandhi.
M iele: A nd regarding race?
Jensen: We com pared notes on ou r treatment, or mistreatment, for
having stuck our necks out on certain aspects o f the race issue, even
though we had each written quite different things fro m entirely d if­
ferent perspectives.
M oynihan was also interested in hearing ab o u t my directing a
large-scale study o f the effects o f complete desegregation o f the
Berkeley public sch ools by means o f two-way busing. T h e research
design was rather ingenious and prom ised som e quite definitive
answers, but he th o u gh t it unlikely th at it could ever be carried out,
because o f political pressures. I h ad already com pleted what we called
the baseline testing the year before, when the Berkeley schools were
quite de facto segregated. M oynihan was politically much less naive
than I, and it turned o u t he was right.
T h e testing th at was intended to assess the first year’s effects o f
in tegration had no soon er begun th an I received a phone call fro m
the assistan t superintendent telling m e that they h a d halted the te st­
ing program , and th a t my research assistants sh o u ld not return to
the schools. I ask ed him “W hy?” an d I still rem em ber his exact
w ords: “ Because the Berkeley S ch o o l D istrict is a p olitical unit, n o t
38
IN TE LLIG E N C E ,
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GENETICS
a research institute.” T h e dean o f the S ch o o l o f E d u catio n in the
U niversity tried to save the situation by offering to assu m e direc­
torsh ip o f the project I had designed, b u t the school authorities
w ouldn’t buy it, and so my research p roject was ended. I learned
that the public protests again st the p roject at school b o ard meetings
were based largely on m y H ER article, which had gotten consider­
able coverage in the local newspapers.
M iele: A nd was that the end?
Jensen: N o , M oynihan later wrote to m e asking i f I kn ew why a
m uch higher percentage o f Black w om en than Black m en passed
the Federal Civil Service exams. A t the tim e I didn’t k n ow this was
a fact, so I looked in to it and found the sam e thing w as true for
college entrance exam s an d aptitude exam s used for h irin g in the
private sector. I to ld M oyn ih an that I w ould do som e research on
this matter.
I wrote a fairly technical book chapter about my findings, titled
“ T h e R ace
X
Sex
X
A bility Interaction.” I sent a copy to Moynihan,
but by then he was no longer in the W h ite H ouse and I ’ve n ot since
had any contact with him. Subsequent studies have n ot consistently
found the mean sex difference in IQ , so I no longer put m uch confi­
dence in the theory.
M iele: A t some point, however, you m ust have changed your point o f
view. D id the scientific evidence lead you to a new political philoso­
phy or did a change in political philosophy lead you to reexamine the
science?
Jensen: Changed my p o in t o f view abo u t what? I did at one time
believe that an individual’s family and social environment an d socio­
econom ic status were by far the m ost influential factors in determin­
ing individual and especially group differences in intelligence and
every other psychological trait. Certainly I hold a rather different
position today, because the scientific evidence that I have studied
JEN SEN ISM
shows overwhelmingly that my previous b elief was wrong. T h e evi­
dence shows that genetic factors and also environmental factors that
have biological effects are much more poten t influences on mental
development than the effects o f family environment. T h e best evi­
dence for this is based on m onozygotic tw ins who were separated in
infancy and reared apart in different fam ilies, and on genetically unre­
lated children adopted into the same family. I f anyone w ants to read
an excellent introduction to this evidence, I suggest D a v id Rowes
b o ok The Limits of Family Influence.
You keep harping on politics. Over the years, I have become
increasingly disillusioned about politics and increasingly suspicious o f
it. W h at I see o f partisan politics and governments interference in
p eop les lives these days lends considerable appeal to the philosophy
o f libertarianism, although I am not a libertarian with a capital L.
M iele: T h en let’s return to science. Take the three p oin ts that made
your HER article so controversial: ( I ) the failure o f com pensatory
education, (2 ) the evidence for a genetic basis to IQ , an d ( 3 ) the like­
lih ood o f some genetic com ponent to the Black-W hite IQ differ­
ence. W ould you say th at’s a fair and accurate definition o f
((J
•
)K
Jensem sm ?
Jensen: I think that is a fair statement so long as no one views it as
som e kind o f dogm a but sim ply conclusions I have reached for the
time being based on my studies o f these matters.
M iele: Suppose the Harvard Educational Review now asked you to come
out with a new and revised edition. W h a t have 30 years o f research
told you that you didn’t know then?
Jensen: T h a t’s a big order! I have answered it at length in my latest
book, The g Factor, but here are a few key points.
First, we have learned that the fam ily environment per se has
exceedingly little— practically zero— effect in creating individual dif­
ferences in mental developm ent by the time children reach early
39
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IN TE LLIG E N C E ,
RACE,
AND
GENETICS
m aturity. This is tru e at least throughout the range o f the norm al,
hum ane home environm ents that are typical o f the vast majority o f
W h ites and o f Blacks in the present-day United States.
Second, I am even less optim istic today than I was in 1969 about
the ability o f com pen satory educational program s to markedly or
perm anently raise either the IQ or sch ool achievement for the vast
m ajority o f children who score below the national average. I now
believe that quite rad ical innovations in education are needed to deal
with the very wide range o f individual differences in potential for
academ ic achievement, regardless o f race. Our sch ools m ust becom e
m uch more diversified in their curricula, the pacing o f instruction,
and their educational goals for p u p ils in every segm en t o f the bell
curve. I have expressed these ideas in m ore detail in a b o o k edited by
R o b e rt J. Sternberg, the noted psych ologist at Yale University.
T h ird , I now believe, more strongly than I did earlier, that m ost o f
the environmental causes o f individual differences in I Q , particular­
ly in the g factor, are biological, rather than social-psychological.
M iele: We’ll examine those strong assertions on intelligence, genetics,
and race in depth in the chapters th at follow. F o r now, let me ask
whether the three heretical Jensenist theses have now becom e accepted?
Jensen: T he only h ard evidence I know o f comes fro m the survey
m ade by Snyder m an and Rothm an in their 1 9 8 8 book The IQ
Controversy, in which over 600 psychologists responded to a long list
o f questions related to my 1969 H ER article. T h e m ajority were in
agreem ent with m y ow n position on every one o f the m ajor points,
including the race question. Three tim es as many said they believed
that both genetic an d environmental factors are involved in the aver­
age Black-W hite difference as said the difference is entirely environ­
m ental.
M iele: I f you could write the final w ord on the career o f Arthur
Jensen and how he becam e one o f the m ost controversial figures in
contem porary science, what would it be?
JEN SEN ISM
41
Jensen: T h a t’s simple: A t som e future p oin t in time neither I nor
Jensenism will any longer be seen as controversial, I f scientific
research is allowed to advance without political interference, the three
parts o f Jensenism will have proved either m ostly right or m ostly
wrong.
I have faith in science as an ongoing and self-correcting process,
not in som e final conclusion. I f that process finally puts m e and
Jensenism down, so be it.
Miele: A n d i f someone else writes that final word, and it’s “A rthur
Jensen returned discussion o f a genetic com ponent for racial differ­
ences in I Q to academic respectability’’?
Jensen: I ’d think the inevitable had finally happened. It should have
always been the case. I believe progress toward this inevitability is rap­
idly accelerating.
Further Reading
For Jensens ow n account o f his 1 9 6 9 Harvard Educational Review article, the origin o f
“Jensenism,” and the reaction to it, see the 67-page preface to: Jensen, A. R . (1 9 7 2 ).
Genetics and education. N ew York: H a rp e r and Row.
For more on Jensen’s work, see the bibliography o f his publications in A ppendix A.
2
WHAT I S I N T E L L I G E N C E ?
The g Factor and Its Rivals
I
n this chapter we d iscu ss the first o f th e three com ponents o f Jensenism:
intelligence. Is it one thing, or many things? Is it even a thing? Have p sy ­
chologists agreed on a definition? I f n o t, what are different theories o f
intelligence?
Surprisingly, Jensen says that experts in psychology have not been able to
agree upon a definition o f intelligence. Because o f this lack o f scientific pre­
cision, he has abandoned using the word. Instead, Jensens research and con­
clusions are about what he terms “general mental ability” or “the g factor”
(the latter is also the title o f his most recent book). T h e theory o f general
mental ability grows out o f the work o f the London S ch ool o f psychology,
started by Sir Francis G alton , Charles D arw in s cousin. O th er famous names
associated with the L o n d o n School and the g factor are those o f Charles
Spearm an (who coined the term g to designate “general m ental ability” ), Sir
Cyril Burt (whose controversial study o f twins and Jensens involvement in the
Burt A ffair are discussed in the next chapter), and Jensens mentor, H an s J.
Eysenck. Today, the theory o f general m ental ability and the g factor are
accepted by many, but by no means all, psychometricians (mental testing
experts) in the United States and worldwide.
Evidence for the g fa cto r comes prim arily from the use o f correlation,
also introduced by G alto n , and o f fa cto r analysis an d other newer and
more pow erful statistical methods. T o understand the theory o f general
43
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IN TELLIG ENCE,
RACE,
AND
GENETICS
m ental ability (g), it m ay be helpful to th ink first about general athletic
ability (let’s call it a). W e m ight start with a hunch that individuals who
excel in one sport (say, the 40-yard dash ) are more likely to perform bet­
ter than average in other athletic events as well. They don ’t have to be the
best or even better than average in every athletic event. B ut those who do
better in one event, we m igh t predict, sh o u ld be more likely to do better in
m ost other events. Or, to p u t it the other way, those who d o below average
in som e events should be m ore likely to d o poorly in others as well. I f so,
we have evidence for a generalfactor o f athletic ability (that is, a single dimen­
sion o f overall athletic prow ess that runs fro m “klutz” at the low end to
“jock” at the high end). B ut is there som e scientific way to test our hunch?
T h e theory o f general mental ability (th e g factor) is like our hunch
about general athletic ability. It says that on average, those w ho do well on
one m ental test also tend to do well on oth er tests. T h e statistical methods
we use to test the g factor (o r our «-factor hunch) are correlation and fac­
tor analysis. T o take the sim plest case, i f the order o f scores (b e st to w orst)
is exactly the same for tw o tests (athletic o r mental ability), their correla­
tion coefficient is + 1 .0 0 . I f the order is exactly the o p p o site for the two
sets o f scores, the correlation is - 1 . 00. I f there is no relation between them
at all, the correlation has a value o f zero. Such ideal correlations are sel­
dom , i f ever, found in real life. But based on the number o f people we test­
ed, we can determine how probable it is th at the correlation we get is sim ­
ply the result o f chance. W h en just about all o f the test scores have p o si­
tive correlations with each other, we have strong statistical evidence for a
general factor— g (for general mental ability) or a (for general athletic abil­
ity).
Besides the general factor, we can analyze the correlations between d if­
ferent tests and sort them into a number o f group factors. E ach group fac­
tor consists o f the tests (o r sports events) th at are the m o st like each other
in term s o f how individuals perform (th at is, they have the highest corre­
lations with each other, even though they have some positive correlation
with the other tests). F o r example, beneath our general athletic factor (a),
we m ight also find group factors for running (r), strength (s), and coordi­
nation (c). T h e running factor might be fu rth er broken dow n into a sprint­
ing factor (sp) and an endurance factor (e). Even though the scores on all
45
W H A T IS I N T E L L I G E N C E ?
the events are correlated, the correlation between sprin tin g and endurance
is m uch higher than correlations between either sprinting or endurance and
any o f the other tests. Likewise, a num ber o f strength tests (for exam ple,
bench press, curls, push -ups) m ight also have the highest correlations w ith
each other.
Evidence that there is one general mental ability, the g factor, rather
than many distinct and independent abilities, is fo u n d in the fact th at
alm ost all mental, or cognitive, tests are positively correlated. Starting with
Spearm an, psychometricians have repeatedly found such a correlation, even
between tests that lo o k very different— for example, tests involving sp atial
relations, vocabulary, filling in m issin g pictures, or reaction tim e.
Rem em ber, this doesn’t mean that the person who gets the best score on
one test has to get the best score on all the others. A ll that’s required to
establish the existence o f a g factor is that, on average, those who d o well
on one test also do well on the others, while those w ho do poorly on one
tend to d o poorly on the others.
N o t all scientists, nor even all psychom etricians, accept the theory o f
general mental ability. O n e o f the th eory’s best-known critics was the late
best-selling science writer and past president o f the Am erican A ssociation
for the Advancement o f Science S tep h en Jay G ould, who argued th at the
evidence for g is little m ore than statistical hocus-pocus.
Psychom etrician R o b ert Stern b erg, editor o f
The Encyclopedia of
Intelligence■, does not deny the existence o f Spearman’s— and Jensens— g fac­
tor. But he thinks it is to o narrow an d fails to capture all that we m ean by
the w ord “ intelligence.” Sternberg believes that look in g at g alone sh o rt­
changes both the individuals tested an d their p oten tial contributions to
society.
In place o f the L o n d on Sch ool’s hierarchical th eory o f a single, all­
pow erful factor o f general mental ability, with a sm all number o f g ro u p
factors subordinate to it, and finally a h ost o f specific factors subordinate
to the group factors, Sternberg has developed his Triarchic T h e o ry o f
Intelligence. For a rough analogy to Sternberg’s m ental triarchy, con sider
the three branches o f the U.S. governm ent— the Executive, the Legislature,
and the Judiciary. Each branch is separate and has its own function; n o one
is superior; and the country cannot be governed w ithout all o f them . T h e
46
IN TE LLIG E N C E ,
RACE,
AND
GENETICS
first branch o f Sternbergs triarchy, Analytical Intelligence, is sim ilar to g.
It involves the ability to see and apply lo g ical relations. T h e second,
Practical Intelligence, m easures street savvy o r “ tricks o f the trade.” An
example o f Practical Intelligence would be a law school graduate who bare­
ly managed to p ass the bar exam (which d oes measure g) b u t went on to
excel as a trial lawyer because o f his skill in “ w orking a ju dge” and “badg­
ering” hostile witnesses, which he picked up hanging around courtroom s
rather than buryin g his nose in law books. T h e final branch o f the triarchy,
Creative Intelligence, is the ability to come up with new an d imaginative
answers to question s instead o f simply applyin g familiar rules to get the
same old an sw ers.T he difference between S tern b erg sT riarch icT h eo ry and
the g factor th eory goes beyond mere classification. Sternberg believes that
Analytical, Practical, and Creative Intelligence can all be increased through
training and th at a person w ho is not as h igh on one can m ake up for it
with high levels o f one or b o th o f the others. A nd even individuals who
are at the very to p in A nalytical Intelligence m ay fall far sh o rt o f what’s
expected o f th em based on g alone, if they haven’t cultivated the other two
aspects.
One o f the theories m o st popular with the general public is Howard
Gardner’s M u ltip le Intelligences. Gardner developed the theory by carefully
examining w hat exceptional people actually do in life. In G ardn er’s view, we
can learn m ore from studying the biographies o f Einstein, Gandhi, and
Picasso to fin d ou t how and w hat they thought, than from know ing which
one o f them h ad the highest (o r the lowest) I Q . H e bolsters th is assertion
with evidence from medical cases in which injuries to certain brain areas
produced specific im pairm ents— for example, speech loss— b u t left other
mental functions untouched. T h e fact that savants, like D u stin H o ffm an s
character in the movie Rain Man, can perform calculations or other mental
operations better than geniuses but fail ordinary I Q tests also supports the
idea of m ultiple, independent form s o f intelligence.
In Gardner's view, the g factor confuses intelligence with a specific type
o f scholastic perform ance. Gardner instead defined intelligence as the
potential to process in form ation in a p articular cultural setting to solve
problems and create things. In place o f Jensen’s g or Sternberg’s Triarchy,
Gardner p ro p o se d seven types o f intelligences— Linguistic, Logical-
WHAT
IS I N T E L L I G E N C E ?
47
M athem atical, Spatial, M usical, Bodily-Km esthetic, Intrapersonal, and
Interpersonal. To these he later added N aturalistic Intelligence (the ability
to recognize plants and anim als and to make sense o f the natural world),
and possibly Spiritual and Existential intelligence as well.
A new rival to the g factor theory comes from evolutionary psychol­
ogy. Som etim es called the “ Sw iss A rm y Knife M o d el o f the M ind,” this
theory says that evolution w ould not produce a general-purpose cognitive
processor like g, but several independent mental m odules. Each module,
like the blades on the Sw iss knife, serves a specific purpose. Since evolu­
tion produced the m odules for im portant functions like recognizing km or
detecting cheaters, they sh ould be present in everyone, with few i f any indi­
vidual differences. John T oob y and L ed a C osm ides o f the University o f
California at Santa Barbara have devised a series o f experiments that have
supported this view.
In this chapter, I cross-exam ine Jensen on the critical issue o f whether
g is a valid scientific measure. I f not, the question o f whether I Q is the
result o f nature or nurture is irrelevant and immaterial, and discussion o f
race differences in I Q is inadm issible. I ask Jensen to produce the evidence
that su p p orts existence o f the g factor against these rival theories. In
responding, Jensen first explains the statistical reality o f g. T h e n he says the
biological reality o f g is dem onstrated by the fact that it has higher correla­
tions than any other psychological measure with a host o f physiological,
anatom ical, and genetic variables, including the overall size o f the brain, its
glucose m etabolic rate while solving problem s, and the speed and com ­
plexity o f brain waves, as well as heritability estim ates (which measure the
effects o f genes versus environment) and inbreeding depression (the harm­
ful effect on the offsprin g o f close relatives).
M iele: T h e concept o f intelligence is central to Jensenism. But many
say that intelligence is like the Suprem e C ourt Ju stices fam ous state­
ment about pornography— everybody knows what it is, but nobody
can define it. H as psychology been able to define intelligence?
Jensen: N o . There are alm ost as many definitions o f intelligence as
there are psychologists who define it. In 19 2 1, the Journal of Educational
48
IN TELLIGENCE,
RACE,
AND
G ENETICS
Psychology asked 15 n oted psychologists to define intelligence and
received 15 different definitions w ith little similarity. In Sternberg
and Detterm an’s 1 9 8 6 book What Is Intelligence?, 2 5 experts in mental
abilities offered their definitions and conceptions o f intelligence.
T h ere was hardly m ore consensus than in 19 2 1. I t s a ridiculous sit­
uation, o f course.
T h e problem is th at the word “ intelligence” is such an umbrella
term . It covers m any definitions, bu t has little i f any scientific preci­
sion. Intelligence is n o t a physical thing like a brain or a liver. It is not
even a scientific co n cep t or a construct. Intelligence is a word like
“ nature.” We know m ore or less what we mean by it, but i f we try to
define it scientifically, we end up either listing a lo t o f other psycho­
logical traits or ju st talking gibberish.
M iele : Then how can you, or anyone, talk about I Q , or m ental abil­
ity, o r any o f the oth er terms we use as rough equivalents o f intelli­
gence?
Jensen: I have solved this problem, at least to my own satisfaction, by
exorcising the word “ intelligence” from the discussion o f individual dif­
ferences within a given species, including Homo sapiens. I use the word
“ intelligence” only fo r objectively observable behavioral differences
between different species. These include sensory sensitivity, perception,
stim ulus discrimination, stimulus generalization, various types o f con­
ditioning and learning, habit reversal, learning set formation, transfer o f
learning, concept form ation, short-term and long-term memory, infer­
ence, reasoning and problem solving at different levels o f abstractness,
and denotative language.
A ll species do n o t display all o f these capacities. But all biologi­
cally norm al m em bers o f a species possess the sam e ones. By “ bio­
logically normal” I m ean those w ithout severe im pairm ents due to
chrom osom al or genetic disorders, trauma, or disease.
T h e scientific stu d y o f individual differences in behavioral capac­
ities within humans (o r any species) calls for a different approach.
T h e variables we m easure must be defined operationally and kept
WHAT
IS I N T E L L I G E N C E ?
explicit at every step. We work from the bottom up. We start with the
sim plest, m ost concrete, and least theoretical definitions, and move
up through a hierarchy, linking each new definition unequivocally to
one at a lower level.
M iele: But how does that get us closer to knowing what I Q , or men­
tal ability, really means?
Jensen: In studying individual differences in humans, we call the low­
est level in the hierarchy an ability. We define an ability as any spe­
cific action that the organism can perform in response to a specific
stim ulus or situation that can be objectively observed and classified,
ranked, or graded on som e kind o f scale. It is a m ental ability only if
little or none o f the differences between individuals are due to dif­
ferences in sensory acuity, physical strength, or agility.
M iele: Fine, but what does that have to do with the g factor?
Jensen: First, the differen t abilities correlate with one another. T he
correlation m atrix (th a t is, the table o f all the correlation s) between
the abilities is then factor analyzed. T h is m athem atical technique
d istills the large num ber o f abilities into a sm aller num ber o f
underlying, independent elements, term ed factors, that account for
m o st o f the differences between individuals. A s an analogy, think
o f how every p o in t on earth can be located precisely in term s o f
ju st three factors— longitude, latitude, and distance above or below
sea level.
Research in psychom etrics, the science o f m ental measurement,
consistently shows th at the largest o f all o f these factors is general
m ental ability or the g factor. Discovered in 1 9 0 4 by the great British
psychologist Charles Spearm an, the g factor measures som e quality or
p roperty o f the brain. It dom inates every other factor and plays some
p art in every m ental ability we can measure. Again, it m ay be useful
to think o f how ju st one number— temperature— gives us a good
idea o f whether it’s colder or warmer in one city than another or on
49
50
INTELLIGENCE,
RACE,
AND
GENETICS
one day than another, though other “ factors” such as hum idity and
w ind chill also affect how warm or cold we feel.
M iele: Can you sketch the history o f the g factor theory? W hy did it
arise? A nd why d id it then fall ou t o f favor— at least in popular
b o o k s on the subject?
Jensen: I ’ve written a b o u t this long an d complex story in detail. In the
latter h a lf o f the nineteenth century, philosophers and psychologists
generally thought the human m ind was made up o f distinct faculties
such as reason, discernm ent, wit, intuition, cleverness, perceptiveness,
im agination, recollection, aesthetic sense— virtually every word
describing some m en tal quality in the dictionary. G alton suggested
that individuals d iffer in some general ability that enters into every
cognitive task a p erson does. H e also tried to show that this general
ability was hereditary. Spearm an also doubted the existence o f so
m any separate, independent faculties. H e realized the only way to
find o u t was to devise som e way to measure each o f them and then
determ ine which on es were highly correlated with one another.
But these conjectures o f Galton and Spearman could not be tested
rigorously until K arl Pearson invented the correlation coefficient
aroun d 1896. Spearm an then began measuring various abilities and
achievements and fo u n d them all positively correlated. H e inferred
that there was som eth in g in com m on that was m easured by all the
tests an d invented a sim ple form o f factor analysis to show the degree
to which each test reflected it. H e labeled this general factor g—
always an italicized, lowercase g. It has now found its way into som e
diction aries (e.g., Random House Unabridged and Webster’s Unabridged),
where it is defined as general m ental ability (n o t to be confused
with the much older g o f physics, which signifies the acceleration o f
gravity).
Spearm an’s g is as im portant to psychology as N ew ton ’s law o f
gravitation is to physics. Interestingly, theories o f the nature o f g —
the g o f psychology an d the g o f physics— are still controversial! Each
g can be measured, b u t we don’t know precisely what it consists of.
WHAT
IS
INTELLIGENCE?
51
Gravitation has been explained in terms o f action at a distance, par­
ticles called gravitons, gravity waves, and the curvature o f space.
N o n e o f these theories is universally accepted as the correct one. It’s
much the sam e for S p earm an s g. It’s best to think o f g as so m e prop­
erty or properties o f the b rain (what else?) th at causes individual dif­
ferences on all cognitive task s to be positively correlated.
T h e g factor is not the result o f some m athem atical m achinations.
There is no longer any d o u b t o f the physical reality o f g. W e know it
is heritable and that it correlates with m any anatomical an d physio­
logical features o f the brain.
Miele: Well, Stephen Jay G o u ld and others have argued th a t g is just
an artifact o f factor analysis.
Jensen: T h a t argument is p o p u la r but scientifically invalid. T h e exis­
tence o f g is not dependent on factor analysis, only its m easurement.
W ould you say that weight doesn ’t exist because it has to be measured
with a scale o f som e kind? M y book Theg Factor gives a detailed expla­
nation o f factor analysis in nonm athem atical terms. L e t m e assure
you that there is nothing at all arcane o r mysterious a b o u t factor
analysis or the g factor.
First, objective m easurem ents with tests o f various abilities have to
be obtained in a fairly large sam ple o f individuals who d iffer in the
measured abilities. T hen we calculate the correlation coefficients
am ong all o f these tests. I f the tests measure various abilities, we find
that their intercorrelations are always positive— that is, individuals’
level o f perform ance on any given test, on average, predicts to some
degree their level o f perform ance on any oth er test, depending on the
m agnitude o f the correlation between the tw o tests. E very pair o f
tests shows this positive correlation. T h is is sim ply an em pirical fact.
T here’s nothing anyone has ever been able to do that will change it.
Even though many attem pts have been m ad e to devise tests o f men­
tal ability that have zero o r negative correlations with each other, no
one yet has succeeded. It appears that zero and nonpositive correla­
tions am ong ability tests are the psychometric equivalent o f perpet­
52
INTELLIGENCE,
RACE,
AND G E N E T IC S
ual m otion in physics— you can imagine them b u t you can never
dem onstrate them in the real world.
Factor analysis is sim ply a m athem atical m ethod fo r dividing up the
am ount o f variation, the total o f the individual differences (techni­
cally termed the “ variance”) in the scores on all the tests into what we
call factors. Som e factors account for more variance than do others,
and factors differ in generality, that is, the number o f different tests in
which the factor accounts for som e o f the variance. W e can array and
display these factors in a quantitative, triangular hierarchy based on
their degree o f generality. At the highest level o f the hierarchy o f gen­
erality— the apex o f the triangle— is general m ental ability, the g fac­
tor. It is followed by two or more second-order g ro u p factors (such as,
say, logical reason in g, verbal-educational skills an d knowledge, an d
visual perception). U n der each secondary grou p facto r are tw o or
m ore prim ary g r o u p factors (su c h as inductive reasoning an d
deductive reasoning under logical reasoning; or arithm etic reaso n ­
ing, which involves both logical reasoning and verbal-educational
skills and know ledge). At the low est level are the actual psychom e­
tric tests such as the Raven’s M atrice s (which is a test o f inductive
reasoning) and letter series (w hich is a test o f deductive reasoning
an d inductive reason in g). (See F igu re 2.1.)
Similarly, the measurement o f gravitation dep en ds upon u sin g
m easuring instrum ents such as m eter sticks and chronometers an d
subjecting the measurements to mathematical calculations, fro m
which we obtain an estimate o f the physicists g, w hose value at the
e arth s sea level happen s to be 3 2 feet per secon d per second. T h e
value differs at various locations on the earth and o n different p la n ­
ets in our solar system .
In principle, there’s no essential difference between the measurement
o f psychometric g an d physical g. I f you think there is an essential d if­
ference, I’d like to know what it is. Both are constructs that can be
defined in terms o f objective procedures applied to data obtained
under standardized conditions that m eet certain criteria o f accuracy or
reliability. Factor analysis isn’t only used in psychometrics. For example,
it’s used in archaeology, paleontology, geology, architecture, anatomy,
WHAT
IS
IN TE LLIG E N C E ?
53
General Factor of Mental Ability
Higher-Order Group
Primary Group Factors
Tests
K ey: L R = L o gical Reasoning
VR=Verbal-Educational Sk ills
and Knowledge
VP= V isual Perception
IR= Inductive Reasoning
D R = Deductive R easoning
A R = Arithmetic R easoning
R M = R aven’s M atrices
L S = Letter Series
Figure 2.1: Factor Analysis o f Mental A bility Tests Showing the General Factor o f M ental
A bility (Spearman's g ), Higher-Order G rou p Factors, Primary G roup Factors, an d Tests.
T h e Raven's Matrices Test is almost a pure measure o f Inductive Reasoning. The Letter Series Test
is also a measure o f Inductive Reasoning, though not so pure. T h e two tests correlate to produce a
Primary Group Factor called Inductive Reasoning.
Letter Series also correlates with other tests (n ot called out in the figure) to form another Primary
Group Factor called Deductive Reasoning.
T h e Primary Group Factors o f Inductive Reasoning, Deductive Reasoning, and Arithmetic
Reasoning correlate with each other to form the Higher-Order Group Factor called Logical
Reasoning.
Logical Reasoning, in turn, correlates with two other Higher-Order Group Factors-—VerbalEducational Skills and Knowledge, and V isual Perception— to produce Spearman's g, the General
Factor o f Mental Ability.
¿ stands at the very top o f the hierarchy o f mental abilities. All o f the mental ability tests, primary
group factors, and higher-order group factors are ¿-loaded. That is, they correlate with ¿ and to some
degree measure i t The ¿-loadings can be thought o f as analogous to the octane ratings o f gasoline or the
pro of o f alcoholic beverages. The higher a test's ¿-loading, the more purely it measures ¿ and nothing else.
Sources: Adapted from A. R. Jensen, Bias in Mental Testing (New York: Free Press, 1 9 8 0 ) and J. C.
Carroll, Human cognitive abilities: A survey of facto r analytic studies ( Cambridge: Cambridge University Press,
1993).
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zoological and botanical taxonomy, quantum mechanics, meteorology,
medicine, sociology, political science, and econom ics as well.
M iele: T h e o ld cliche in law school is that a gran d jury will indict a
ham sandwich i f a DA orders one. T he old cliché I heard in graduate
school was th at what you get ou t o f a factor analysis depends on what
you put in an d how you analyze it.
Jensen: T h a t overworked canard is either m eaningless or wrong. I have
heard it only fro m persons who have never d on e a factor analysis and
who know next to nothing abo u t it. I’m n o t blam ing you fo r bring­
ing it up— I know it’s your jo b to be provocative, and you’re right,
this point does provoke me a bit. I guess I ’ve becom e rather tired o f
it. So what can I say?
You get factors from a factor analysis, and you didn’t put th ose fac­
tors in to begin with. You begin just with scores on a variety o f tests.
T h e correlational structure o f the tests th at is revealed by factor
analysis is n ot apparent in ju st looking at all the test scores o r even
by inspecting the matrix o f correlations am o n g the scores, although
such inspection can give us a fair idea o f whether the matrix prob a­
bly contains a general factor— for example, all positive correlations
and many o f them large. O f course, it is ob vious that no factors can
emerge that are not latent in the various test scores, but you can say
exactly the sam e thing ab o u t perform ing quantitative analysis in
chemistry; in som e complex substance you are analyzing, you can’t
find, say, calcium in some specific amount un less calcium is actually
present in the substance. Similarly, in factor analysis, you can’t iden­
tify a factor as spatial ability unless the collection o f tests you have
analyzed contains some tests that measure sp atial ability. N o r can you
tell by sheer inspection how m uch a particular test reflects, say, spa­
tial ability; the sam e test m igh t also reflect verbal ability, or we m ight
find that there are several different types o f sp atial ability (a s in fact
there are), and the test will always reflect g as well. O r you m igh t not
even recognize from sim ple inspection that in addition to g and a
numerical ability factor, a test o f mental arithm etic also reflects a ver­
WHAT
IS I N T E L L I G E N C E ?
bal com ponent or a sp atial com ponent until the arithm etic test is
included in a factor analysis with a number o f other tests th at reflect
these com ponents.
Miele: C an you provide a sim ple but real-life example o f factor analy­
sis?
Jensen: Years ago when I to o k a course on factor analysis one o f our
hom ework assignments was to analyze a set o f 50 different body
measurements— the diam eters o f the waist and the hips, the lengths
o f the to tal arm, upper arm , lower arm, and so on— obtained in a
sample o f 1 0 ,0 0 0 women by the British garm ent industry. In effect,
factor analysis was used to “ so rt” the full set o f 50 measurements
into a sm aller number o f factors. To be technically precise, a factor is
defined as a latent variable, or a hypothetical source o f variance, that
is com m on to two or m ore variables. Conceptually, you m igh t want
to think o f a factor as a dim ension that is m ade up o f the m easure­
ments that “ go together,” that is, a subset com posed o f th ose m eas­
urements that correlate highly with each other and much less so with
all the other measurements.
T h is was long before the advent o f to d ay s statistical software
packages and personal com puters that can do the job in a couple o f
minutes. Back then factor analyzing so many variables was a godaw ­
ful calculating job. It to o k a full week o f punching keys on an elec­
trical desk calculator.
Miele: A n d the results o f your Herculean labor?
Jensen: T here was a very large general factor in all these b o d y mea­
surements— call it “general body size.” T h a t means that all 5 0 meas­
urements correlated with each other to form a single factor (o r dimen­
sion) o f “general body size” on which each woman could be placed. In
other words, on average, tall women tended to have longer arm s, legs,
fingers, and feet and also broader shoulders and hips and wider feet
than shorter women. T h is makes sense because if it weren’t true,
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women couldn’t buy ready-made clothes based on one size but would
have to get them tailor-m ade. T h e next largest factor was “latitude ver­
sus longitude.” A n d this agrees with the fact that after their overall
size, many garm ents are then “ sized ” or categorized by “width” (fo r
example, narrow an d wide, or A, B, C , D ). Shoes are a good example.
T h e n came a factor o f “torso length versus leg length,” which matches
the fact that special sizes o f slacks are available for women with rela­
tively short and relatively long legs relative to their overall height. T h e
next factor, as I recall, was “bust girth versus hip girth ” (that is, gen­
erally bigger above or below the waist). So the original set o f 5 0 body
measurements could be m apped in term s o f only those factors, just as
any place on earth can be m apped in terms o f longitude, latitude, and
altitude. Adding one or two more factors to those four accounted for
som e 9 0 percent o f the total variance in all 5 0 b o d y measurements.
A s you can see from the examples, the results o f such a factor analy­
sis have real econom ic value to the garment industry.
W hen we do p erform a sim ilar factor analysis on a battery o f p sy­
chom etric tests there is always a large general factor, g (sim ilar to the
“ general body size” factor described in the exam ple I just gave), fo l­
low ed by various second-order grou p factors such as logical reason­
ing, verbal-educational skills and knowledge, visual perception, and
so on (analogous to the other body-size factors in the example).
(R efer back to Figu re 2.1.)
M iele: Let’s turn to the m ajor rivals to g theory that are popular
today: Sternberg’s Triarchic T h e o ry o f Analytical, Practical, and
Creative Intelligence; Gardner’s T h eo ry o f M u ltip le Intelligences,
which includes Linguistic, Logical-M athem atical, Spatial, M usical,
Bodily-Kinesthetic, Interpersonal, and Intrapersonal form s o f intelli­
gence, to which he has recently added N aturalistic, Spiritual, and
Existential form s o f intelligence; and evolutionary psychology’s
M o d u lar T heory o f the M ind.
Isn’t the difference between the g factor, Stern b erg’s Triarchy, and
G ardner’s M ultiple Intelligences really a matter o f terminology, n ot
science? D on’t they all tell part o f the story?
WHAT
IS I N T E L L I G E N C E ?
Jensen: I t’s to o simple ju st to say that these theoretical differences
are merely a m atter o f term inology. I f you perform ed a facto r analy­
sis o f the traits in S te rn b erg s and G ardn er’s systems alo n g with all
the cognitive and personality variables we can now m easure, m ost o f
them w ould fall into one o f the group facto rs that are already known
and quite well described in John B. C a rro ll’s “ three-strata m o d el” o f
abilities, o r the “big five” m odel o f p erson ality (Conscientiousness,
O penness, Extraversion, N euroticism , an d A greeableness). O ne or
two new g ro u p factors m igh t also emerge.
Miele: W ell, I guess Stern b erg’s theory gets a lo t o f sup p ort from our
everyday observations o f “ absent-m inded professors” an d “ street­
sm art” characters with little or no education.
Jensen: Sternberg’s triarchic m odel is an attem pt to define the traits that
contribute m ost to achievement and success o f one kind or another in
the intellectual domain. In a comprehensive factor analysis that included
established reference tests o f ability and personality, I would predict that
m ost o f the individual differences in Sternberg’s triarchy (analytic abili­
ty, practical ability, and creativity) would be absorbed by g, while much
o f the rest o f it would fall into the personality domain. T here would
also be a number o f small group factors and specificity, too, m osdy in
his measures o f “ practical intelligence,” which are highly specific to par­
ticular kinds o f knowledge useful in certain jo b settings.
Except fo r g, the im portance o f all these various abilities and traits
is problem atic.
Miele: W h y problematic? W h y is g always the exception?
Jensen: Because the relative importance o f each group ability factor
or personality factor does depend on the context in which it operates.
g is the exception because it enters into perform ance in virtually every
context.
Miele: A n d Gardner’s T h e o ry o f M ultiple Intelligences?
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Jensen: Until Gardner provides standardized measures for several o f
his multiple “ intelligences,” they can t be included in a factor analysis.
T h a t doesn’t m ean they don’t exist or aren’t im portant. But w ithout
som e objective way o f measuring the things G ardner calls “ intelli­
gences,” his theory is more speculative literary psychology than p sy ­
chometrics. T h ere’s nothing to sto p anyone from claiming that A1
C apone displayed the highest level o f “ Criminal Intelligence,” or that
Casanova was “ blessed” with exceptional “Sexual Intelligence.” A n d i f
you’re going to use the word “ intelligence” that loosely, you m ight as
well say that C hess Grand M aster Bobby Fischer is one o f the w orld’s
great athletes. A fter all, chess players are called “ w ood pushers,” and
Fischer can “ push w ood ” with the b e st o f them.
M iele: But doesn’t the fact that brain damage and certain genetic d is­
orders produce very specific deficits in behavior (su ch as being unable
to recognize faces but still recognize voices or geom etric shapes) and
the existence o f savants like D u stin H o ffm an ’s character in the m ovie
Rain Man give G ardner’s theory m ore hard neurological support than
there is for the g factor?
Jensen: T hey do indeed support the “ multiple abilities” aspect o f
G ardner’s theory. N o one denies that. But that does not contradict
either the existence or the em pirically dem onstrated im portance o f
the g factor.
T h ere is one p rop erty o f g th at is seldom n oted bu t is highly rel­
evant to all other cognitive facto rs and talents an d special abilities
th at are independent o f g. I call it the threshold aspect o f g. It
m eans that these specific abilities o r talents a lm o st never result in
notable life achievements unless the person who p ossesses them has
a level o f g above som e threshold value. By defin ition, savants have
very low I Q scores and a low level o f g. But they display aston ish ­
ing skills— say, num erical calculation , playing the piano by ear,
m em orizing pages from a teleph on e directory, or drawing ob jects
fro m m em ory w ith nearly p h o to g rap h ic accuracy. A s remarkable as
these savants certainly are, they never become m athem aticians, sc i­
WHAT
IS I N T E L L I G E N C E ?
entists, professional m usicians, or artists. T h a t requires a fairly high
level o f g as well.
T h ere are also people o f quite norm al general m ental ability who
possess som e extraordinary savant-like ability. I tested Shakuntala
Devi, probably the w orlds greatest m ental calculating prodigy, in my
reaction-tim e laboratory. H er I Q score was good, but n ot exception­
al. But her calculating feats are amazing. W e do know that functional
efficiency in a particular domain can be markedly enhanced through
extensive experience and practice.
T h e g threshold is im portant in m o st fields o f endeavor. W hen the
Institute o f Personality Assessm ent and Research at Berkeley tested
people recognized as successful in fields that call for special talents,
all o f them scored above average on I Q tests, with the vast majority
scoring higher than 9 0 percent o f the general population. T h e very
highest levels o f achievement, o f course, require an absolutely
extraordinary talent— actually, genius. But it is utterly silly to think
that N ew ton , Beethoven, or M ichelangelo possessed only a mediocre
level o f g. A level o f g beyond the 9 0 th percentile is probably neces­
sary, though certainly not sufficient, for recognized achievement in
science, the arts, or leadership in politics, the military, business,
finance, or industry. But as Galton em phasized, that requires excep­
tional zeal and industry as well.
M iele: Research in the emerging disciplines o f evolutionary psychol­
ogy an d cognitive neuroscience has also focused on the search for dis­
tinct m odules in the brain, each with a specific function, rather than
on the g factor and som e general p roperty o f the brain. S o do you
accept or reject the existence o f m ental m odules?
Jensen: Som e people think that demonstrating the existence o f modules
in the m ind proves that there are only separate abilities, each governed
by a different module, and disproves the existence o f g. T h is confuses
individual differences and factors with the localized brain processes
underlying the various kinds o f abilities. Som e m odules such as
quick-recognition m em ory o f hum an faces or three-dimensional
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space perception can’t possibly show up in a factor analysis o f ability
tests. T hese abilities are virtually universal in people who do not have
brain damage or som e genetic disorder. T h e individual differences in the
general population are just too slight fo r these im portant abilities to
emerge as factors. W e’ve only discovered them when the modules under­
lying them have been neurologically damaged, resulting in conspicuous
malfunctions, such as perceptual distortion, lack o f recognition memo­
ry, or various aphasias (the inability to use or to understand speech, or
specific components o f language, such as numbers or written words).
M iele: T h en what d o you think the m odu les are?
Jensen: T h ey are distinct, innate brain structures that have developed
in the course o f hum an evolution, characterized by the various ways
that inform ation or knowledge is represented by the neural activity o f
the brain. T h e main m odules involve specific functions we’d class as
linguistic (verb al/au d ito ry /lexical/sem an tic), visuo-spatial, object
recogn ition , n um erical-m athem atical,
m usical, an d kinesthetic.
A lthough these m odules generally exist in all norm al people, they are
striking by their absence in people w ith highly localized brain dam ­
age, whereas their presence is highlighted in savants.
T h e various m odules have distin ct functions, bu t they are all
affected by brain characteristics such as chemical neurotransmitters,
neural conduction velocity, am ount o f dendritic branching, and
degree o f myelination o f axons. A n d factor analysis shows that the
specialized mental activities associated with different modules are
correlated to some degree.
M iele: Okay, let’s accept the reality o f the g factor an d that it is the
single best predictor o f how well you can get along and advance in a
m odern technological society. But w hat does g have to do with the
abilities and skills th at were needed fo r that 99 percent o f human
evolutionary history before we developed agriculture? How could
evolution select for the ability to d o factor analysis, solve verbal
analogies, or mentally rotate a matrix?
WHAT
IS I N T E L L I G E N C E ?
Jensen: T h a t is on e o f the really b ig questions fo r behavioral gen et­
ics, evolutionary psychology, an d psychom etrics. W hy are there
such great in dividual differences between hum ans in the abilities to
learn m athem atics, com pose m u sic, play the violin, write poetry,
draw pictures, h it baseballs, s h o o t baskets, an d so on? A nd how
can there be a gen etic basis for th ese differences? T h e se abilities are
all so recent in h um an h istory th a t they couldn ’t have been su b ­
jected to selection, natural or otherw ise, over the course o f hum an
evolution.
T h e only answer psychology has offered is that the genetic and neu­
rological basis for these specialized abilities was originally developed
by natural selection for other activities that were im portan t for survival
in our prehistoric past. In historic tim es, elements o f these traits could
be applied to new tasks. M odern abilities like the ones you m entioned
were never explicitly selected, bu t they have been able to utilize many
o f the same neurological structures that were selected for other p u r­
poses in our remote past. T h is m ay not be provable, but it appears
entirely plausible.
F o r some reason that you m igh t guess, g is a less popular idea than
“m ultiple intelligences” or these oth er rival views.
M iele: Maybe G ard n ers naturalistic, spiritual, and existential intelli­
gences are som ew hat airy-fairy concepts, but aren’t spatial, m usical,
bodily-kinesthetic, intrapersonal, an d interpersonal also im portant? I
certainly would play a lot better flute i f I had perfect pitch and win
a lo t more racquetball matches i f I h ad better eye-hand coordination.
Jensen: I’m sure th at’s true. But i f you had to be in the lowest 10 per­
cent o f the population in g or in m usical ability, athletic ability, artis­
tic ability, or any o f those other skills and abilities, which would you
choose? How m any points o f f your I Q score based on the Raven’s
Progressive M atrices (one o f the purest measures o f g') would you be
w illing to trade fo r a com m ensurate increase in your score on the
Seashore M easures o f M usical T alents or a test o f eye-hand coordi­
nation?
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W h y d o m ost parents and teachers show only a m odest amount
o f concern when a child with average or above-average I Q shows lit­
tle aptitude for m usic, sp orts, dancing, or drawing, but are quite
concerned when a child has a very low IQ ? It’s because g predicts
school achievement, employm ent, and m uch more. It does no good
to belittle the reality o f g or its far-reaching consequences. Studies
com paring the lives o f people in the low est 3 percent o f the pop u­
lation in I Q with those in the top 3 percent have shown the differ­
ences are greater and m ore far reaching than you m ight im agine. If
you were free to d o so, you’d have no difficulty choosing between
having a high or a low IQ . We don’t like to think about this issue,
but that m akes it no less real. O ur character is tested by how we deal
with it.
M iele: O u r character is tested by how we deal with what? W h at is it
we don’t like to think about?
Jensen: W e are hesitant and reluctant to recognize, at least openly, the
existence o f large individual differences in general mental ability. It’s
a sensitive issue, especially with respect to group differences in IQ
and scholastic achievement, which have many im portant personal,
social, and economic consequences.
W h en people are asked about their own I Q , nearly everyone con­
siders h im self or h erself average or above, which is statistically
im possible. Few people m ind adm itting they have p oor m usical abil­
ity or artistic ability. But no one says this abo u t their intelligence, and
people generally avoid discussing the relative intelligence levels o f
other people.
People look for all kinds o f reasons except I Q level to explain poor
scholastic perform ance. O ften there are other reasons that have noth­
ing to d o with intelligence, but by far the m o st frequent basis for very
p oo r scholastic achievement is below-average general m ental ability.
D ealing with these sensitive issues kindly and charitably requires wis­
dom as well as intelligence. W isdom im plies intelligence, but the con­
verse is n ot necessarily true.
WHAT
IS I N T E L L I G E N C E ?
M iele: Can you provide any biological evidence for the existence or
im portance o f g?
Jensen: Yes, that’s easy. I developed the “ m ethod o f correlated vec­
to rs” for that purpose. (See Appendix A o f my m ost recent book, The
g Factor, for a detailed explanation o f this m ethod.) It shows that g is
m ore highly correlated with a greater num ber o f biological and other
nonpsychological m easures (including heritability estim ates, the elec­
trical activity o f the brain in response to an external stim ulus, overall
brain size, inbreeding depression, P E T scans o f the brains glucose
m etabolic rate during m ental activity, and nerve conduction velocity
in the brain) than any other mental factor that is statistically uncor­
related withjj.
Inbreeding depression is a well-documented genetic phenomenon.
It is the reduction in any measurable trait (height is a g o o d example)
that occurs in the offsp rin g o f parents who are very closely related
genetically, such as siblings or close cousins. W hen the children o f
cousin marriages are com pared against the children o f parents with
sim ilar intelligence an d background but who are not related, the chil­
dren o f cousin m arriages are shorter and they also average five to
seven points lower in IQ . O f all psychom etric m easures, the g factor
shows the m ost inbreeding depression. Inbreeding depression occurs
on brain size as well.
A ll o f this evidence and more shows that g is not the result o f any
m athem atical legerdem ain associated with the process o f factor
analysis, but is a real physical and natural phenomenon.
M iele: T h e m ethod o f factor analysis does, however, require measur­
ing or ranking people and that’s the source o f an argum ent against
the g factor and the whole London Sch ool o f psychology that has
both a scientific and a larger philosophical part.
T h e scientific p art is that unlike learning, which we can demon­
strate in one individual, or gravity, which we can describe m athem at­
ically based on the observation o f one cannon ball, the concept o f g
is based on m easuring and com paring people. All the statistics you
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use involve the m athem atical m anipulation o f relative standings, not
absolute measures with a true zero an d equal intervals.
T h e broader philosophical argum ent is that underlying the whole
L o n d on School o f psychology is som e hidden agenda o f measuring
and inevitably ranking o f people, i f n o t groups— and the individual
or group doing the ranking always com es out on top. S o even i f it’s
scientifically valid, doesn’t the underlying philosophy o f the GaltonSpearm an-Jensen tradition run counter to our notions o f democracy
and even the m arketplace? M ost A m ericans believe we’re all equal, if
not now, then with a little more effort— or one o f those many train­
ing courses you see on T V infomercials, or another governm ent p ro­
gram , or the help o f G o d — we will be. S o isn’t the view point o f the
L o n d on School anti-Am erican in that sense?
Jensen: Your question requires a four-part answer, at least.
First, recognizing individual differences is neither anti-American,
anti-democratic, nor anti anything else. T h e statem ent o f the nation’s
founding fathers— “ all men are created equal”— refers to equality
before the law and this now includes equality o f all civil rights.
Individual differences in all kinds o f hum an traits— physical features,
m ental abilities, personality— have been obvious to everyone as far
back as anyone knows in recorded history. Individual differences were
no d ou bt im portant in prehistoric tim es as well.
Second, equality o f talent is not characteristic o f any “ marketplace”
I have ever heard of. C an every pianist in the musician’s union play like
Paderewski or H orow itz and com m and the same kind o f fees that they
got? Are all employees of, say, General M otors, equally qualified to be
its C E O ? W hat percentage o f the population could make it through
medical school, or sing at the Met, get into big league baseball, or win
a N o b el Prize? Because the abilities or talents demanded by these kinds
o f performance are very scarce in the general population, they can com ­
m and greater rewards in an open market. There are more people will­
ing to pay to hear H orow itz in concert or buy his recordings than there
are people willing pay the same am ount to hear a perform ance by their
local piano teacher.
W H A T IS I N T E L L I G E N C E ?
T hird, because everyone sees all this human variation in many d if­
ferent behavioral traits, and because psychology is the science o f
behavior, it is the jo b o f psychology to study the nature o f individ­
ual and group differences in all aspects o f behavior, including those
regarded as m ental abilities.
Fourth, o f course people can study and practice and learn new
things, and can acquire new knowledge and skills, or improve their
existing skills w ith further practice. T h a t’s what training and educa­
tion are all about. But there are also individual differences in predis­
posin g factors that are largely dependent on genetics and the physical
structures that they control in the brain and nervous system. T h ese
result in individual differences in the ease and sp eed with which train­
ing, education, practice, and experience produce certain behavioral
outcom es. A num ber o f individuals all highly m otivated to succeed
in the acquisition o f some knowledge or skill, and all given the sam e
opportunities fo r learning and practice, will show m arked differences
in accom plishm ent assessed after X months or Y years o f effort. T h e
perform ance level o f each individual will have im proved in absolute
term s, but the differences between individuals in perform ance will
also have increased over the p e rio d o f learning and practice. A n d
there are some things that som e individuals can never achieve with
any amount o f training, practice, and effort.
T h e best single predictor o f these individual differences in the
rate o f learning an d the level th at can be attain ed in a great m any
areas o f know ledge and skills th at people regard as being o f a
m en tal nature is the g factor th at we have been talkin g about. A n d
we know that in dividual differences in the g fa c to r n ot only have a
genetic com pon en t but other b iological co rrelates such as the
brain ’s overall size, electrical activity in response to a stim ulus, g lu ­
cose m etabolism during m en tal activity, an d nerve conduction
velocity. As for g ro u p differences, whether the g ro u p s are races, or
social, or econ om ic classes, i f the groups live in the same culture
an d have sim ilar educational op p o rtu n ities, then any group d iffe r­
ences in g are really ju st aggregated (or accu m u lated) individual
differences. T h a t is, psychom etrics has found no causal factor th at
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makes racial differences or social class differences any different
than individual differences.
T o speak o f “ ranking” individuals or groups, as I em phasized ear­
lier, m akes no scientific sense unless you can specify a specific dim en­
sion or trait on which the individuals or groups differ. O n e o f the
aims o f factor analysis is to delineate the dim ensions (called factors)
in a given dom ain o f m easurements.
M iele: S o the G alton-Spearm an-Jensen viewpoint has no hidden
agenda?
Jensen: I don’t know o f any agenda other than advancing ou r scien­
tific understanding o f hum an behavioral differences. A nd there’s cer­
tainly nothing in the least “ hidden” about it. Both G alto n and
Spearm an, and I too, have written a lot about what we think on these
topics— about our theories and research. W e’ve all been rather
extraordinarily outspoken in our many publications. O n e o f the
tenets o f my own philosoph y is to be as open as possible and to strive
for a perfect consistency between my thoughts, both spoken an d pub­
lished, in their private an d public expression. T h is is essentially a
G andhian principle, one th at I have long considered worth striving to
live by.
Further Reading
T h e inability o f psychologists to reach a definition o f intelligence is d iscu ssed in: The
Editors (1 9 2 1). Intelligence an d its measurement: A symposium. Journal of Educational
Psychology, 12, 1 2 3 —147, 1 9 5 - 2 1 6 , and 2 7 1 - 2 7 5 ; and Sternberg, R . J„ and D etterm an, D.
K. (1 9 8 6 ). What is intelligence? Contemporary viewpoints on its nature and definition. N orw ood , N J:
Ablex.
T h e classic statement o f the theory o f general m ental ability is: Spearm an , C. E.
(1 9 2 7 ). The abilities of man: The nature and measurement. N ew York: M acm illan. See also Jensen's
articles on Spearm an and Sir Francis G alton in: Sternberg, R . J. (E d .) ( 1 9 9 4 ). Encyclopedia
of intelligence. N ew York: M acm illan.
For a detailed explanation o f factor analysis, the g factor, and the statistical and bio­
logical evidence for the existence o f g see Jensens m ost recent book: Jensen, A. R . (1 9 9 8 ).
Thegfactor: The science of mental ability. W estport, C T : Praeger. M ore conversational, less tech­
W H A T IS I N T E L L I G E N C E ?
67
nical descriptions appear in: Jensen, A. R . (1 9 8 1 ). Straight talk about mental tests. N e w York:
Free Press; Herrnstein, R . J., and Murray, C . (1 9 9 4 ). The hell curve: Intelligence and class struc­
ture in American life. N ew York: Free Press; as well as: Miele, F. ( 1 9 9 5 ). For whom the bell
curve tolls: Charles M u rray on IQ , race, class, Gould, Gardner, and the Clintons. Skeptic,
3 (3 ), 3 4 - 4 1 .
G o u ld ’s criticism o f Jensenism and the L on d on School appears in: Gould, S . J. (1 9 9 6 ).
The mismeasure of man. (R evised and expanded edition.) N ew Y ork: N orton.
F o r Sternbergs Triarchic Theory o f Intelligence, see: Sternberg, R . J. (1 9 8 8 ). Beyond
IQ : A triarchic theory of human intelligence. N ew York: Cam bridge University Press; as well as:
M iele, F. (1 9 9 5 ). R o b e rt Sternberg on "th e bell curve.” Skeptic, 3 (3 ), 7 2 - 8 0 .
T h e T h eory o f M u ltip le Intelligences is described in: G ardner, H . (1 9 8 3 ). Frames of
mind. N ew York: Basic B oo ks; and in: Gardner, H . (1 9 9 3 ). Creating minds. N ew York: Basic
Books.
Evolutionary P sych ology’s M odular T h e o ry o f the M in d is described in: Cosmides, L.,
Tooby, J., and Barkow, J. (E d s.) (1 9 9 2 ). The adapted mind. N e w York: Oxford University
Press; and more conversationally in: M ithen, S. (1 9 9 6 ). The prehistory of the mind: The cogni­
tive origins of art, religion, and science. New York: T h am es and H u d so n . For an introduction to
this emerging discipline, see: Miele, F. ( 1 9 9 6 ). T h e (im )m oral animal: A quick and dirty
guide to evolutionary psychology and the nature o f human nature. Skeptic, 4 ( I ) , 4 2 —49.
F o r the currently m ost-accepted factor-analytic m odels o f mental abilities and per­
sonality, respectively, see: Carroll, J. B. ( 1 9 9 3 ). Human cognitive abilities: A survey of factor-ana­
lytic studies. Cam bridge: C am bridge University Press; and W iggins, J. S . (1 9 9 6 ). Thefive fa c ­
tor model of personality: Theoretical perspectives. N e w York: Guilford Press.
F o r more on Jensen’s work, see the bibliography o f his publications in A ppendix A.
3
NATURE,
NURTURE, OR BOTH?
Can Heritability
Cut Psychology's Gordian Knot?
W
hat do baseball stars Barry B on ds (who set a new m ajor-league
record by hitting 7 3 home runs in one season), C a l Ripken, Jr. (w ho
surpassed L o u Gehrig’s record o f consecutive gam es played), R oberto
Alomar, Sandy Alomar, Jr., and Ken Griffey, Jr., have in common? Each is
the son o f a former m ajor league player or manager. Joh an n Sebastian Bach,
one o f the greatest com posers in the history o f W estern music, was the
father o f Carl Philipp Emanuel, Johan n Christian, Johann C hristoph
Friedrich, and W ilhelm Friedm ann Bach, who also were com posers, though
none as illustrious as their father. W olfgang Amadeus M o z a rt was the son
o f L e o p o ld M ozart, also a composer, bu t not o f his son ’s caliber. A n d
there are the Bernoullis in science and the Bolyais in m athem atics, and the
novelists Alexandre D u m as pere etfils. A ctress Drew Barrym ore comes fro m
a theatrical family that includes her grandfather John Barrym ore and his
sister Ethel, brother Lion el, and son John Drew Barrym ore. And then there
are the Fondas: Henry, Jane, Peter, and m o st recently, Bridget.
We all know there are “ dynasties” in sports, m usic, science, and m ath ­
ematics. T h e question is, why? Are genes for athletic, m usical, or intellec­
tual ability passed from parents to children, like th ose for hair color or
69
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RACE,
AND
GENETICS
blood type? O r are these abilities acquired, the way a child learns his or her
parents’ language or religion? O r perhaps the genetically g ifte d children o f
genetically gifted parents are doubly endow ed by being reared in home
environments that foster their inborn talents?
Is it nature, or nurture, or both? T h a t is psychology’s G ordian knot.
Heritability is the sword th at Jensen believes has cut the knot.
In this chapter we d iscuss the secon d o f the three pillars o f
Jensenism— individual differences in IQ are more the result of thefact that we inherit dif­
ferent genes than of thefact that we grow up in different environments— and the politi­
cal and scientific controversies that have swirled around it. In Jensen’s defi­
nition, “ environment” encom passes every cause o f individual or group dif­
ferences that is not genetic. It includes biological factors (su ch as exposure
to toxic chemicals, m other’s age and health, problem s during childbirth, and
even incom patibility in b lo o d type between the mother and fetu s) and quan­
tifiable factors linked with socioeconom ic status, or S E S (su ch as family
income, num ber o f books in the home, and tim e spent by parents with their
children) as well as qualitative cultural factors (such as grow ing up in a poor,
Black, inner-city neighborhood versus an affluent, mostly W h ite suburb).
Jensen does not deny th at environment affects IQ . But, he says, not
only are genes more im p ortan t than environment, but the biological envi­
ronmental factors are m ore powerful than cultural and socioeconom ic fac­
tors. T h e average difference in IQ between siblings reared in the same
household (where family S E S and culture are pretty m uch the same) is
greater than the average difference in I Q between families fro m different
S E S and cultural groups.
Con trary to the hopes an d expectations that have sh aped social policy
since the days o f the G reat Society, genes play by far the biggest role in
producing differences in I Q , followed by environmental differences (espe­
cially biological ones) between siblings who grow up in the same family.
D ifferences in S E S between families finish dead last. T h erefore, even the
m ost extreme government policy that m ade all families exactly equal in
income, num ber o f book s in the home, quality o f schools, tim e spent with
parents— even providing professionals to assist disadvantaged parents in
child rearing— could n ot elim inate or even substantially reduce IQ differ­
ences. O r so Jensen says.
NATURE,
NURTURE,
OR
BOTH?
71
Jensen supports his conclusions by citing studies o f I Q that use the
m ethods o f quantitative genetics, especially a statistic called heritability.
Placing the case o f Nature v. Nurture before the C ourt o f Quantitative
Genetics m eans that we m ust treat it like a civil suit, rather than a criminal
case. F o r a specific criminal charge, say vehicular homicide, the defendant
is found either 100 percent not guilty (an d walks free) or 1 0 0 percent
guilty. In civil suits such as auto accidents due to faulty original equipm ent
or subsequent repair work, negligence can be apportioned. T h e judge can
find each o f the defendants 100 percent liable, 0 percent liable, or any­
where in between. For example, the judge m ay decide that the auto m anu­
facturer is 6 0 percent liable and the repair shop 4 0 percent liable for the
faulty brakes that caused the p la in tiff’s accident. Likewise, quantitative
genetics renders its decision by apportioning the relative roles o f genes and
environment in producing individuals’ differences through a statistic called
heritability.
F o r any measurable trait— height, the age at which teeth erupt, intelli­
gence, or b loo d pressure— heritability is defined as the propo rtio n o f the
total variance in the trait that is due to genes, and not to the environment
(including the biological environment described earlier). W e can even
determine the heritability o f traits like charisma or sex appeal, provided we
can reliably and accurately rate individuals on those traits.
T o understand heritability and the controversies that have swirled
around it, it is necessary to understand ju st what that term does and does
not mean. W hen Jensen states that the heritability o f I Q in a particular
group o f people is 0 .7 5 , he is not saying that som eone with an I Q o f 100
got 7 5 I Q points from his genes and the remaining 2 5 from his environ­
ment. W h a t he is saying is that 75 percent o f the individual differences— the
variation or the total variance in I Q — in that group is because o f differences
in their genes, and the remaining 2 5 percent o f the total variance is due to
differences in their environment (including the biological environment).
Q uantitative genetics grew largely ou t o f the work o f S ir R on ald A.
Fisher in which varieties o f plants were grown in different types o f soil and
given different amounts o f fertilizers or nutrients. Suppose that we are
m easuring differences in oil yield o f genetically different corn seeds grown
in the sam e soil and given the same am ount o f nutrients. Any significant
72
IN TELLIG EN CE,
RACE,
AND
GENETICS
differences that we find must be the result o f genetic differences between
the seeds. Conversely, differences between genetically identical seeds o f
corn grown in different soils or given different am ounts o f fertilizer m ust
be the result o f environmental differences. In the case o f genetically diverse
seeds grown in different soils and given different am ounts o f fertilizer, a
heritability o f 0 .6 0 w ould mean that 6 0 percent o f the measured differ­
ences in oil yield were the result o f genetic differences between the seeds,
and 4 0 percent o f the differences were due to the different environments
(so il and fertilizer) in which they were grown.
Jensen and other hereditarians applied this sam e reasoning to the study
o f differences in I Q and other hum an behaviors. Ethically, our society does
n ot allow behavioral scientists to place children in different homes, give
them different nourishm ent, or m anipulate any other factor sim ply for
research purposes. N o r would behavioral geneticists want to do so. Instead,
they rely on “ natural experiments” in which the resemblance in any trait
between different degrees o f kinship (th at is, twins, siblings, unrelated chil­
dren reared together) is compared with the degree o f similarity predicted
by genetic theory. By definition, however, these natural experiments lack the
control o f laboratory plant or anim al studies.
O n e o f the m o st informative natural experiments com pared identical
twins reared apart. Identical (also called m onozygotic, or M Z ) twins devel­
op from a single egg fertilized by a single sperm that divides and then
develops as two em bryos. Som etim es the division is not complete and we
get conjoined twins (com m only called “Siam ese tw ins” ). But in m ost cases,
M Z twins are two (o r m ore) genetically identical individuals— in effect,
natural human clones. Ju st about everyone has known at least one pair o f
twins who look— an d even act— alike. But again the question is why?
Identical twins are often dressed alike by their parents and treated alike by
others. T o unravel the Gordian kn ot o f nature versus nurture, we need to
lo o k at the rare cases o f identical twins separated early in life (the earlier
the better) and reared in different hom es (the m ore different the better).
T h e se are often term ed M Z A (m onozygotic twins reared apart) m human
behavior genetic studies.
T h e correlation between the IQ s o f M Z A twins (w ho inherited the
sam e genes but were then reared in different environm ents) provides the
NATURE,
NURTURE,
OR
BOTH?
73
best single estim ate o f the heritability o f intelligence. T he average correla­
tion in I Q from the various stu dies o f M Z A tw ins is about 0 .7 8 . W orking
from the opposite direction, the fact that the correlations in I Q between
parents and their adopted children (about 0 .1 9 ) an d between a d o p ted chil­
dren and the natural children o f the adopting parents (about 0 .3 2 ) are low
also argues for a high heritability o f IQ . At least fo r the W hite population
o f the U nited States and Europe, heritability stud ies o f various degrees o f
kinship consistently show that different genes are responsible fo r abo u t 75
percent o f the to tal differences in IQ . T his is true even for brothers and
sisters in the sam e home (rem em ber, they share only about 5 0 percent o f
their genes— to be technically precise, 50 percent o f their genetic vari­
ance— on average). (See Table 3.1 on page 9 4 .)
Another result from these stud ies that is predicted by Jensen an d those
who attribute a m ajor role to genes but that poses a problem to antiJensenists is that the heritability o f I Q increases with age, while the corre­
lation between adopted children and their adoptive parents an d also the
correlation between adopted children and the natural children o f their
adoptive parents both decrease w ith age. In this respect, I Q acts like height,
obesity, tooth size, or any num ber o f physical traits for which environment
plays a m ajor role early in developm ent but fo r which genes— an d usually
several genes acting together— increasingly steer the course o f develop­
m ent. Consider how the environmental factor o f severe m alnutrition or ill­
ness in infancy can permanently im pair a person’s general health fo r the rest
o f his or her life, but may cause less devastating though still adverse effects
i f experienced later, when the b o d y is more fully developed. A n d those o f
us who reach m iddle age becom e painfully aware o f how much ou r fami­
ly’s m edical h istory becomes increasingly pertinent to our own probability
o f encountering such diseases an d conditions as high b lo o d pressure,
cataracts, diabetes, stroke, cancer, or heart disease.
But the devil— and to m any anti-Jensenists, a quite literal and evil
one— is in the details. They argue that when identical twins are separated
and placed in different hom es, their environments are really n o t that dif­
ferent in term s o f the critical factors. Rarely, they argue, is one identical
tw in placed w ith poverty-stricken parents on S k id Row while the other
grow s up in the lap o f luxury on Park Avenue. T h e y also question whether
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INTELLIGENCE,
RACE,
AND
GENETICS
twins are even representative o f the population as a whole. A s an envi­
ronm ental factor tending to m ake twins more alike, anti-Jensem sts point
to the fact that tw ins share the sam e womb. In the case o f adoption , they
question whether adoptive parents really treat their adopted children
exactly as they d o their biological offspring. A n d they point ou t th at in
m any cases the fact that these children are being placed for ad o p tio n may
be evidence o f early environmental problem s, such as the use o f d ru gs or
alcohol by the m oth er (Jensen concedes that such biological prob lem s are
im portant).
T h e m ost pow erful attem pt to topple the seco n d pillar o f Jensenism
was the n otorious B urt Affair. T h e late Sir Cyril Burt, a founder o f the
hereditarian L o n d o n School o f psychology, h ad published a num ber o f
studies showing th at the correlation in I Q for identical twins reared apart
was 0 .7 7 . Jensen, in his 1969 Harvard Educational Review article, cited this fig­
ure and other sim ilar findings by Burt on the inheritance o f m ental abil­
ity. After Burt’s death, a number o f anti-Jensenists carefully scrutinized
B u rt’s published research. T hey n oted that the correlations between twins
hardly changed even after Burt claim ed he had a d d ed new sets o f tw ins to
his database. T h e n similar discrepancies were uncovered in B u rt’s other
publications. N o t only the anti-hereditarians but B u rt’s biographer as well
concluded that the aging scholar h ad begun to lose touch with reality and
n ot only had co oked up the correlations but even invented nonexistent co­
authors to su p p o rt his claim o f having conducted new research. Jensen
counters that the work o f two subsequent authors seems to have vindi­
cated Burt, and m ore importantly, that even disregarding Burt’s results the
preponderance o f evidence su p p orts the conclusion that about 7 5 percent
o f the variation in I Q is because o f genes, not environment— a figure very
close to Burt’s 0 .7 7 . Jensen then describes the state-of-the-art research that
recently has identified some o f the specific genes fo r IQ .
A
P
r im e r
o n
V
a r i a n c e
a n d
H
e r it a b il it y
T h e methods o f quantitative genetics allow us to determine the p ro p o r­
tion o f the variation in any m easurable trait that is due to heredity and the
proportion that is due to environment.
NATURE,
NURTURE,
OR
BOTH?
75
T h e easiest way to get som e idea o f the variation w ithin any group
o f people and in any m easurable trait— whether I Q , b lo o d pressure,
height, or weight— is to subtract the low est figure fro m the highest.
Statistician s refer to the difference between these two figures as the
“ range.” B u t even i f there are many p eop le in the group, as there are in
m ost so cial science experim ents, a single extreme case can d isto rt this
value. F o r example, i f we were m easuring variations in incom e, home
runs h it in a season, or b o o k s sold, the inclusion o f ju st one person at
the to p o f the scale (e.g., Bill Gates, B arry Bonds, or D an ielle Steele)
would really inflate the range.
T h e next thing we m igh t try would be to calculate an average (term ed
the mean) for the group an d then to subtract the mean from each person’s
score. T h e result would be a series o f values that statisticians call “ devia­
tions from the mean.” F o r a score above the mean, the deviation would be
a positive number; for a score below the mean, a negative number. To get
some idea o f the average deviation from the mean, we m ight just add all
these deviations and then divide by the num ber o f people we measured.
But the sum o f all the positive and negative deviations has to equal zero,
and so the result would n o t tell us anything at all.
Since we re interested in how much variation there is in the group, were
really n ot concerned with whether the deviations from the grou p mean are
positive num bers or negative numbers. Either way, they represent variation.
T h e sim plest and m ost direct approach in this case would be to ignore the
signs (whether positive or negative), add up all the deviations from the
mean, and then divide by the number o f people in the group to get a value
that represents the average deviation from the mean.
Statistician s have don e essentially this, first squaring each deviation
from the m ean (that is, m ultiplying the num ber by itself), which makes
all the values positive num bers. T h e squared deviations from the mean then
are added together, and the sum is divided by the number o f people in the
group under study. T h e result is called the variance. (T h e w idely used sta­
tistic know n as the standard deviation is the square root o f the variance.)
Variance has a very im p o rtan t characteristic statisticians call “ additivi­
ty,” which m eans that the to tal variance is always equal to the sum o f its
com ponents.
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INTELLIGENCE,
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G ENETICS
T here are com plex m athem atical reasons for using the squared devia­
tions from the mean rather than sim ply ignoring the plus and minus signs.
For the purposes o f the present discussion, it’s enough to note that using
the squared deviations allows us to com pute the variance, which we can
then break down into the percentage o f the total variance due to genes and
the percentage due to environment; and that these two percentages m ust
add up to 1 00 percent (the total variance). As a very rough analogy, think
o f asking a financial advisor to go over your fam ily budget. H e breaks
down your total m onthly income into the percentage you m ust spend on
necessities such as taxes, rent or m ortgage, utilities, and car payments ver­
sus the percentage th at you can either save or spend as you wish.
Analysis o f variance is central to the way quantitative genetics esti­
m ates the relative roles o f heredity and environment. T h e total variance in
any trait is broken dow n into the p rop o rtio n due to genes— called “ heritability,” and represented by the sym bol h2— and the prop o rtio n due to the
environment, term ed “ environmentality,” and represented by the sym bol e2.
Both h2 and e2 can be further broken dow n into their com ponents (ju st as
the percentage o f spen din g on necessities and on niceties could be broken
down further in the fam ily budget analogy). T h e sum o f these com ponents
m ust always equal the to tal variance.
An E x am p le
S u p p ose we were testing a group with only four subjects. (R eal studies use
many m ore.) L e ts call them A, B, C, and D.
T h e ir systolic b lo o d pressure readings (o r their tested IQ s) are:
A = 1 0 0 ; B = 120; C = 9 0 ; and D = 9 0 .
T h e mean is:
(1 0 0 + 120 + 90 + 9 0 = 4 0 0 )/4 = 100
T h e deviations fro m the mean are:
A = 100 - 1 0 0 = 0
B = 1 20 - 1 0 0 = 2 0
NATURE,
NURTURE,
OR B O T H ?
77
C = 90 - 100 = -1 0
D = 9 0 - 100 = -1 0
N o te that the sum o f these deviations equals zero:
0 + 20 + (- 10) + (- 10) = 0
T h e squared deviations from the mean are:
A = 0 2= 0
B = 202 = 400
C = - I 0 2 = 100
D = - I 0 2 = 100
T h e variance in our group, then, is:
(0 + 4 0 0 + 100 + I 0 0 ) / 4 = 6 0 0 / 4 = 150
S o the standard deviation in our example is equal to the square ro o t o f
150, which is approxim ately 12.25.
T h e Im portant T h in gs to Rem em ber
A bout Variance and H eritability
•
T h e p roportion o f the total variance in any trait that is due
to genes is term ed the heritability of the trait and is represent by
the sym bol h2.
For example, i f we find that differences in genes explain
8 0 percent o f the variation in blood pressure in a group o f
people, the heritability o f b lo o d pressure in that group is
0 .8 0 ( 12 = 0 .8 0 ).
• T h e heritability o f 0 .8 0 refers to the variation in blood pres­
sure in that grou p — not the percentage o f the blood pressure
reading for any individual in the group— th at is due to genes
rather than environment.
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INTELLIGENCE,
•
RACE, A N D
GENETICS
Further, h2 = 0 .8 0 is the heritability in that group. B lood
pressure (o r I Q or any trait) could have a different value if
we tested a different group.
•
However, heritability studies o f I Q have been largely con sis­
tent in reporting values o f Zdfrom 0 .5 0 to 0.80, even fo r dif­
ferent countries or different races or ethnic groups.
•
W hatever proportion o f the variance is not due to genes
(1 .0 0 — A2) is due to the environment.
T h e proportion o f the total variance in any trait that is not
due to genes is termed the environmentality of the trait and is repre­
sented by the symbol
d.
In our example, 2 0 percent (th at is,
100 percent - 8 0 percent) o f the variation in blood pressure
would be due to the environment. (T o be technically precise,
1.0 0 - h2 =
d
+ measurement error. F o r I Q and other psycho­
logical tests, the error is usually between 5 and 10 percent.
M edical measures such as cholesterol level, blood pressure, and
X-ray interpretation often have higher measurement errors.
Even reading length from a ruler involves some measurement
error.)
• In hum an research, the environm ent includes n o t only
socioecon om ic facto rs such as incom e, quality o f sch ools,
and years o f education , bu t also b io lo g ica l factors su ch as
exposure to toxic chem icals, and injuries during p re g ­
nancy.
•
Both heritability and environmentality can be broken down
further into com ponents. But no m atter how detailed the
breakdown, the com ponents must ad d up to the to ta l vari­
ance (th at is, the to tal variance m ust equal the sum o f its
parts).
Miele: Well, i f the first tenet o f Jensenism— the g factor, which we
talked about in Chapter I — isn’t controversial, I hope yo u ’re not
going to tell me that the secon d tenet— th at the differences in g are
NATURE,
NURTURE,
OR
BOTH?
79
m ore the result o f heredity rather than environment— isn’t contro­
versial either.
Jensen: T h e fact that g is more strongly genetic than m ost other psy­
chological variables is not really controversial am ong empirical
researchers in this field. It is highly controversial only in the popular
m edia. Just try to find any real controversy am ong the experts who
know the research on this issue. T h e re ’s always a han dful o f dissenters
regarding any bo d y o f empirical knowledge, o f course, even in the
scientific community. Unfortunately, the m ass m edia have presented
the views o f this sm all number o f highly vocal dissenters as the pre­
vailing position.
M iele: N o m atter which side I talk to on issues like this I find there’s
only one thing the two sides agree on— blaming the m edia that their
side isn't accepted and the other side is given any voice at all. Can you
provide any solid evidence to su p p o rt your claim o f m edia bias?
Jensen: Anyone who wants a thorough presentation o f expert op in ­
ion am ong behavior geneticists and psychom etricians on the subject
and a scholarly analysis o f the p op u lar m edia’s disto rtio n o f it should
read The IQ Controversy: The Media and Public Policy by M ark Snyderman
and Stanley Rothm an.
M iele: Again, I ’ve found that b o th sides in any controversy point to
b o o k s that they claim set the record straight. W h at m akes Snyderman
and Rothm an’s b o o k the definitive statement? It wasn’t published by
the American Psychological A ssociation (A PA ) or the Behavior
Genetics A ssociation (BG A ), was it?
Jensen: N o, but they came to their conclusions after surveying those
best qualified to judge, the m em bers o f the Behavior Genetics
A ssociation and the Tests and M easurem ents D ivision o f the
Am erican Psychological A ssociation. A nd an article sum m arizing
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their findings and conclusions was published in American Psychologist,
the APA’s house journal.
Miele: Are you telling me that i f I did a content analysis on the m ost
popularly used Psych 101 textbooks or polled the m em bers o f the
APA, I’d get a paraphrase o f what you ju st to ld me?
Jensen: I’m not sure what you’d get from a random poll o f the APA
m em bership. But i f you polled experts in biological psychology,
comparative psychology, behavioral genetics, and psychom etrics, you
would find a solid consensus that individual differences in I Q and the
g factor have a large genetic component. T h e APA itself has published
an introduction to the genetics o f individual differences, Nature,
Nurture, and Psychology, edited by R obert P lom in and Gerald M cC learn,
which also agrees with that consensus.
Miele: A nd is that consensus reflected in psychology textbooks?
Jensen: I ’m afraid it is not. I recently exam ined the chapters on intel­
ligence and individual differences in a sam ple o f introductory psy­
chology textbooks. T h e conceptual errors and m isinform ation in
their discussions o f the heritability o f I Q are appalling, even in some
o f the m ost widely used textbooks. T h ere are a few exceptions, but
on the whole, undergraduate psychology textbooks are m isinform ing
hundreds o f thousands o f college students on this subject every year.
T h is has gone on for at least 3 0 years. T h e disparity between spe­
cialist bo ok s in this field and the treatm ent o f the subject in m ost
undergraduate texts is scandalous. Studen ts m ight as well read pop
psychology articles in the Sunday new spaper supplements.
Miele: You seem to have little but contem pt for introductory psy­
chology texts and to get awfully worked up about them. W hy?
Jensen: I ’d rather have students read W illiam Jam es’s Principles of
Psychology, originally publish ed in 1 8 9 0 , than to read the pabulum
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now passed o f f on undergraduates as “ Introductory Psychology.”
A nd the introductory course has a considerable influence on who
will and who w ont m ajor in psychology. I still read James fo r pleas­
ure now and then, but it alm o st sickens m e even to thum b through
m ost o f the introductory psychology b o o k s published in recent
years. T h ey represent a dum bing-dow n o f the whole field! I doubt
that textbooks o f this ilk exist in the b iological or physical sciences,
because they wouldn’t be tolerated by either the students o r the fac­
ulty. O f course there are a few perfectly respectable introductory
texts in psychology. It is u p to instructors to be discrim inating and
search for them.
M iele: Perhaps part o f the problem comes fro m the origins an d asso­
ciations o f the words. Before the scientific term “heredity,” we had
the word “ hereditary.” “ H ered itary” can m ean “ genetic, n o t environ­
m ental” ; but it can also m ean “ by right o f birth,” as in “ the heredi­
tary D uke o f N orthum berland.” T he term “ genetic” is easily con­
fused with “ eugenics.” D o you think the origins and association s o f
the words “ heredity” and “ hereditary” with aristocracy, an d later, o f
“ eugenics” with N azism , have cast a dark cloud over the scientific
study o f m ental ability?
Jensen: T h ey shouldn’t, but I ’m sure they have cast a shadow, i f not
your dark cloud. And hopefully our increase in scientific knowledge
is clearing the skies. “H ered ity” simply refers to the transm ission o f
genes from parents to their offspring; genes are the physical units o f
heredity. “ H ereditary” m eans about the sam e thing, but o ften implies
the passing on o f parental genes that affect som e observable charac­
teristic o f one or both parents to one or m ore o f their offsp rin g. A
“hereditarian” is som eone w ho holds that som e part o f the variation
in m ental and behavioral as well as physical traits is attributable to
genetic variation within the species. T h e w ord “ genetic” p ertain s to
genes, or to characteristics know n to be influenced by genes.
Miele: A nd “ eugenics” ?
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Jensen: When S ir Francis Galton coined the word “ eugenic,” which lit­
erally means “ g o o d beginning” o r “ good genes,” he meant the heredi­
tary basis o f characteristics such as good health, longevity, the absence
o f birth defects o r physical or mental handicaps, personally and
socially advantageous mental abilities, and favorable personality traits.
T o dispel any T h ird Reich o r H olocaust g u ilt by association
im plied in your question, let me q uote exactly w hat G alton said abo u t
eugenics in his autobiography, Memories of My Life:
M an is gifted w ith pity and oth er kindly feelings; he has also
the power o f preventing m any kinds o f suffering. I conceive it
to fall within h is province to replace N atural Selection by other
processes that are more m erciful and not less effective. T h is is
precisely the a im o f Eugenics.
Even if we d on ’t use the term, eugenics is practiced throughout the
civilized world to d a y through genetic counseling, amniocentesis, and
DNA
testing fo r
various gen etic diseases su ch as Tay-Sachs,
H untington’s chorea, and many oth er genetic anom alies. And it is the
prospective parents who are requesting these fam ily planning proce­
dures. Government is not ordering them. W h at opposition there is
these days com es fro m a few on the political left an d many m ore on
the religious right.
M iele: You still haven’t answered the second p a rt o f my question—
D o you think all th is talk o f genes and heredity, and its association
w ith aristocracy, eugenics, and even Nazism , have forever bedeviled
the scientific study o f the nature o f mental ability?
Jensen: N o, I don’t believe that the scientific study o f the inheritance
o f mental ability is really bedeviled by these wrong or evil things from
p a st history. I don ’t put the G altonian conception o f eugenics, as
stated in the quote I gave you, in th at category. N o r d o I see any intrin­
sic relationship between aristocracy or Nazism and the scientific study
o f the g factor, behavior genetics, an d individual or group differences.
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There are those, however, who for whatever reason deny the reality
o f individual differences or the evidence that individual differences
have genetic as well as environmental causes. Som e have tried to link
psychometrics and behavioral genetics with Fascism , N azism , H ider, or
whatever and hereditanan psychologists have been subjected to such
defamatory propaganda. T h e New York Review of Books review o f my 19 8 0
b o ok Bias in Mental Testing (whose findings were subsequendy confirm ed
by a special committee o f the N atio n al Academy o f Sciences) ran with
a cartoon o f me in what looks like a N az i storm trooper uniform! A n d
a Canadian psychologist who studies the evolutionary basis o f racial
differences in mental ability was caricatured in a newspaper cartoon as
shaking hands with Hider. T h a t abysmally low level o f criticism m ere­
ly shows their desperation. T h ey aren’t worth recognizing.
M iele: Okay. T h en let’s get back to the technical term used in behav­
ior genetics, “ heritability.”
Jensen: Here we have to shift gears drastically, because “ heritability”
means som ething very different from the term s “ heredity,” “heredi­
tary,” and “ inherited.” I’m willing to bet that only a minority o f
Ph.D.’s in psychology know the definition o f “ heritability.” S o let’s
get its m eaning straight right now.
Technically, “ heritability” is defined as the statistically estim ated
proportion o f the population variance in a given trait that is attrib­
utable to genetic factors. Variance (Var.) is calculated as the arith­
metic average (o r mean) o f all the squared deviations o f each in di­
vidual measurement from the overall mean o f all the measurements.
[See the Prim er on Variance and H eritability that begins on page 7 4 ,
after the introduction to this chapter.]
H ere’s the key point: T h e heritability o f any trait is the prop ortion
o f the total trait variance due to genetic variance. A s a very rough
analogy, think o f the pie charts showing federal revenue you see in
the newspaper that show, say, 2 5 percent com es from corporate
income tax, 7 0 percent from individual incom e tax, and the rem ain­
ing 5 percent from excise taxes, tariffs, and inheritance tax.
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Geneticists make a further distinction between narrow heritability and
broad heritability. Technically, narrow heritability is the proportion o f total
variance due to the additive effects o f genes only. Broad heritability con­
sists o f the narrow heritability plus the variance resulting from genetic
interactions whose effects are not simply additive (that is, not 2 + 3 =
5, but 2 x 3
= 6); from assortative m ating (the tendency o f like to
marry like, which increases total variation); and from a very special com ­
ponent called genotype-by-environment (G
X
E ) covariation. G
X
E
covariation refers to cases in which genes and the environment are both
favorable (o r unfavorable) for the development o f a particular trait, as
in the case o f a child who is genetically gifted musically and also grows
up in a highly musical environment, like M ozart.
Miele: S o are you saying th at heritability can cut the nature-nurture
Gordian knot? W hat abo u t the classic exam ple o f the sam e seeds
sown in different soils that goes back to C harles Cooley, the founder
o f the A m erican Sociological Association? O r maybe back even fur­
ther, to Jesus in the Parable o f the Sower an d the Seeds:
Behold the sower went ou t to sow. And as he sowed, it happened
one indeed fell by the roadside; and the birds o f heaven ate it.
And another fell on the rocky place where it did not have much
earth. A n d it sprang up at once, due to n ot having deepness o f
earth. A nd the sun rising it was scorched. A nd through not hav­
ing root, it was dried out.
And another fell am ong the thorns, and the thorns grew up and
choked it, and it did not yield fruit. And another fell into the good
ground and yielded fruit, going-up and increasing; and one bore
thirty, and one sixty, and one a hundred-fold. (M ark 4:3—8 )
Jensen: I love your apt quotation from the N e w Testament. Its poetic
language offers a welcome relief from all my technical terminology. And
todays behavior genetic research pretty much tells us the same thing.
Essentially, heritability estim ates d o
cut the nature-nurture
Gordian kn o t fo r any m easurable traits by separating the total varia­
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85
tion into the part due to variation in genes and the p art due to vari­
ation in environment. I prefer the term s “ genetic influences” and
“ nongenetic influences” because so many people think environment
m eans ju st the psychological, social, and cultural m ilieu in which a
person grows up. T h e se nongenetic influences begin virtually at the
m om ent o f conception. They have direct effects on the brain’s devel­
opm en t and are probably the m o st im portant o f all environmental
effects on ¿.T h ey include intrauterine conditions related to the m o th ­
er’s age, health, and blood type; incom patibility between mother and
fetus; nutrition; certain m edications; and substance abuse. T hen there
are perinatal conditions such as anoxia, birth traum a, and extreme
prematurity. And also postnatal conditions— m ainly early nutrition
and the various childhood diseases. M y analysis o f IQ differences in
M Z (m onozygotic, or identical) tw ins, who have the same genes, su g­
gests th at nearly all these effects are disadvantageous.
M iele: But does th at mean that factors like home environment, p ar­
ent-child interaction, schooling, an d family income have no effect on
a person ’s g?
Jensen: N o , later environmental influences have their effects largely
on what a person does with his or her level o f g rather than on the
level o f g itself. T h e se effects are fully recognized by geneticists— the
sources o f environmental variance are every bit as interesting to them
as the genetic variance. T he im p ortan t point is that by means o f
quantitative genetic analysis, such as the calculation o f heritability, we
are able to get g o o d estimates o f the relative strengths o f the envi­
ronm ental and the genetic influences on a given characteristic in a
given population at a given time. A n d by the same m eans we can lo o k
at the relative effects o f genes and environment on a particular trait
over the course o f development, fro m infancy to later maturity.
M iele: T h a t all seem s so contrary to everything we’ve come to believe
about the im portance o f education. D o you have any evidence to su p ­
p o rt those statements?
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Jensen: Consider the heritability o f height. In our population, height
has a heritability o f about 0 .3 0 in infancy, which gradually increases,
up to about 0 .9 5 in early adulthood. I Q shows a similar developmen­
tal increase in heritability, going from about 0 .4 0 in early childhood to
about 0 .7 0 in adulthood, then up to about 0 .8 0 in older adults. I f envi­
ronment and experience were the chief determinants o f m ental growth
throughout our life span, you would predict that the longer we have
lived, the lower the heritability o f IQ , because the difference between
our life experience and those o f our kin sh ould accumulate. But just the
opposite is found to be true. I Q behaves like height and other physical
traits in that the resemblance between genetic relatives increases with
age, despite their differences in cumulative life experience.
M iele: But critics point out that heritability estimates are dependent
on the population studied and the co n dition s under which that pop­
ulation developed. D o n ’t those qualifications dull the edge o f the
behavior genetic knife? R ather than cleanly cutting the nature-nurture
G ordian knot, what we see is a fuzzy and frayed tangle.
Jensen: T h o se critics write as i f behavioral geneticists weren’t aware o f
these points. T h e basic genetic m odel is th at the total variance we see
in any trait, term ed the phenotypic variance ( var.P), is com posed o f
the genetic variance ( var.G) plus the nongenetic variance (var.P), also
called the environmental variance, or
var.P — var.G + var.P.
H eritability ( ¥ ) is sim ply the ratio o f the genetic variance to the
total variance:
h2— (var.G)/(var.G + var.P?)
S o by definition, heritability can vary over some range o f values
depending on the degree o f genetic variation in the population (var.G)
and the am ount o f environmental variation (var.P). I f you look at the
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second equation, you can see that the sm aller var.E becom es, the high­
er h2, until you reach the p oin t at which there is no environmental vari­
ation at all (that is, var.E. = 0.00), at which point V - LOO. As var.G
gets smaller, b2also decreases, until h2— 0 .0 0 and t — 1 .0 0 — h2— 1.00
- 0 .0 0 = 1.00. I f everyone’s environment is pretty m uch the same,
heritability will be very high because the only thing that really varies is
the genes. Likewise, i f there is very little genetic variation, as for exam­
ple in highly inbred strains o f corn or laboratory mice, heritability will
be very low. In a country where part o f the population suffers from
m alnutrition while others are well fed, the heritability o f height is
lower (because o f greater environmental variation) than in a country
where everyone is reasonably well nourished.
T h e other point about heritability follow s as a corollary— a heri­
tability estimate is n ot a constant like the speed o f light, nor is it
m eant to yield some single, constant value. Rather, heritability is an
inherently inconstant population statistic, like the average birthrate,
the average mortality, or the average height o f adult m en or women.
T h e heritability o f I Q estim ated in different studies varies as a func­
tion o f the test used, the age o f the subjects, and the degree to which
the subjects vary in socioeconom ic status and educational level. The
heritability o f I Q fluctuates somewhat from sample to sam ple and
study to study from abo u t 0 .4 0 to 0 .8 0 , w ith the average fo r all stud­
ies falling somewhere between 0 .6 0 and 0 .7 0 . But such an overall
average isn’t really as informative as know ing the heritability in a par­
ticular population under specified conditions.
M iele: But I’ve heard Jerry Hirsch, a distinguished psych ologist who’s
done som e pioneering w ork in behavior genetics, say th at heredity is
a fact but heritability estim ates are ju st hand waving th at implies
greater certainty than really exists. A n d he quotes no less an author­
ity than Sir Ronald A . Fisher, who developed many o f the methods
o f quantitative genetics, to support his criticism.
Jensen: I just explained why uncertainty is inherent in any heritabil­
ity estimate. N o one who knows anything about Fisher’s views could
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im agine that he w ou ld disagree w ith anything I’ve sa id on this su b ­
ject. Fisher merely p o in te d out that a properly estim ated heritability
coefficient is a p o p u latio n statistic, and, like any p op u lation statistic,
it has a clearly defin able probable error— that is, its likelihood o f
being o f f the m ark by a given am ount. T h e same th in g is true for ju st
ab o u t every scientific measurement, say a statistical determ ination o f
the birthrate in the U .S . population in the year 2 0 0 2 . W ould you
then echo Jerry H irsch and say that a newborn child really exists, but
the birthrate is ju st hand-waving?
M iele: Since we can’t an d wouldn’t w ant to perform controlled breed­
ing experiments w ith humans, ou r knowledge a b o u t the roles o f
heredity and environm ent and the heritability o f m ental ability comes
from comparing iden tical twins, nonidentical twins, other relatives,
and adopted children.
Before sum m arizing the results o f those studies, co u ld you sketch
the logic behind th o se studies?
Jensen: I covered th is material in d e p th in the courses on behavior
genetics and on theories o f intelligence that I taught at the University
o f C alifornia at Berkeley. It says som eth in g about the social sciences
in contem porary A m erica that after m y retirement n o one was hired
to teach these courses in either the psychology o r the education
departm ents.
M o s t o f the statistical m ethodology was originally developed to
solve problem s in genetics, especially as applied to agriculture. But it’s
just as applicable to the field o f behavior genetics, which came into
its own in the 1 9 7 0 s with the fo rm ation o f the Behavior Genetics
A ssociation ( o f w hich I was a charter member) an d their journal
Behavior Genetics, in w hich I have publish ed a number o f articles.
M iele: Okay. Let’s try a really short course, for now.
Jensen: Well, the essen tial ideas did indeed come fro m S ir Ronald A.
Fisher’s elaboration o f the basic principles o f heredity discovered by
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Jensen’s favorite photo of himself because "it shows me in my most typical setting and activity" —
in his study at home; working on another article or book. (Taken but never used by L ife magazine)
Gregor M endel, which we call M endelian genetics. M endel dealt
entirely w ith traits in which variation is due to a single gene locus that
can take tw o distinct fo rm s— like his w rinkled peas or sm ooth peas,
or red flowers or white flowers. I f you grow these flowers in a uni­
form environment (w hich M endel d id ) you get either two or three
distinct variants, depending on whether the trait m anifests either
genetic dominance (where the offspring appear just like the dom inant
parent b u t show no trace o f the recessive parent) or genetic additivity
(where the offspring display a blending o f the two parental form s).
L e ts say we have a gene with two possible form s (term ed “ al­
leles” )— an d let’s call one R (fo r R ed) and the other w (fo r W hite)—
that determ ine the color o f the flowers. Each flower has two alleles
for color (R and w), w ith one allele com ing from each o f its two par­
ents. T h e n each flower m u st have one o f the following four possible
allele com binations (technically term ed “ genotypes” ): RR (R ed-R ed),
ww (W h ite-W h ite), Rw (R ed-W hite), or wR (W h ite-R ed). T h e RR
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genotype is pure red (technically term ed “ hom ozygous” ), and its
phenotype (th at is, what we observe) is a red flower. T h e ww gen o­
type is pure white (again h om ozygous), and its phenotype is a white
flower. T h e wR and Rw genotypes (technically term ed “heterozy­
gous ) are the sam e; their different designations sim ply indicate that
a different parent provided the allele to the offsp ring (which for our
present purposes doesn’t m atter).
Now, the genotypes o f the o ffsp rin g o f one o f our pure red RR
flowers and a pure white ww flow er can be either RR, Rw, wR, or ww.
L e t’s suppose flower color has genetic dom inance and red is d o m i­
nant over white. T h en the RR, Rw, and wR genotypes all result in the
R ed phenotype (th at is, a red flow er). Only the pure white ww geno­
type produces the phenotype fo r a white flower. Given sufficient
numbers, about three fourths o f the offspring o f pure red flowers
and pure white flowers will be red flowers and the remaining onefourth or so will be white flowers— the 3:1 ratio M endel described.
M an y blood types in humans also show genetic dominance.
But now suppose were dealing with a different trait, say, stem height
at maturity. We again have two homozygous, or pure, strains. Let’s call
them I T (hom ozygous tall) and tt (hom ozygous short). Now, the geno­
types o f the offspring o f one o f our homozygous tall I T flowers and a
homozygous short tt flower can be either: TT, Tt, tT, or tt. Unlike color,
stem height has additive inheritance— that is, neither T nor t is dominant or
recessive, but instead they blend. T h e homozygous tall TT genotype
produces the tall phenotype. T h e hom ozygous short tt genotype pro­
duces the short phenotype. T h e heterozygous Tt and tT genotypes,
however, produce plants that are intermediate in height between the
two parental strains. So for stem height, the offspring would display
three phenotypes, not two as was the case for color. A bout one fourth
would be tall, one-half would be intermediate, and one fourth would
be short. Im portant human traits such as height and I Q show poly­
genic, rather than simple M endelian, inheritance.
M iele: T h e ratios you’ve given are statistical. T h e y ’re what you see
with sufficiently large numbers. I f I start breeding a couple o f pea
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plants ou t on my balcon y I ’m not g oin g to see these exact ratios in
each and every generation. Right?
Jensen: O f course. T h a t ’s one o f the defining properties o f quantita­
tive genetics— its p rediction s are probabilistic. T h a t m eans that our
experiments in human behavior genetics require statistical inference.
And this often makes the results harder to explain an d harder for
nonspecialists to understand. But it also means— and th is is im por­
tant in relation to a lo t o f your earlier questions abo u t the historical
and p olitical associations o f the nature-nurture problem — that the
antiquated ideas about trying to breed a master race an d so on just
don’t m ake any scientific sense in term s o f modern genetics. W hat we
can do genetically, even when and if we w ould want to, is really rather
m odest.
A nd there are always trade-offs, even when we do apply selective
breeding. Consider the “ green revolution” that developed grams with
higher yields. They’ve been achieved by selecting for only one or two
genetic characteristics, such as kernel size or oil content, in very stan­
dardized environments. But human behavior is the result o f thou­
sands o f genes and develops in all so rts o f environments, including
environments our individual genetic tendencies lead us to select or
create fo r ourselves. T h e human genom e has about at least 3 0 ,0 0 0
and perhaps twice th at m any genes. T h e central m echanism o f behav­
ior is the brain, and at least half o f all the genes in the human
genome are involved w ith the brain, an d the effects o f about one
third o f all the genes are entirely unique to the brain.
Miele: Anything m ore in your short course in genetics?
Jensen: Yes, one more thing, about genetic dominance. T h e genes for
the characteristics th at prove to be advantageous to survival over the
course o f natural selection are usually dom inant genes, while the
characteristics that prove disadvantageous are usually recessive. T h e
two mechanisms that cause this are spontaneous m utation and natu­
ral selection. M ost m u tated genes con fer undesirable characteristics
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(th at is, phenotypes) in their hom ozygous (that is, “ p u re” ) combina­
tion. T h ey remain recessive, and selection very gradually reduces their
frequency until it is nearly at the rate o f spontaneous m utations for
that gene. M utation s that confer som e selective advantage, or
D arw inian fitness, increase in frequency over successive generations
and are dom inant over the less advantageous alleles at the same locus,
which are therefore said to be recessive.
F o r some traits, however, it is m o st advantageous to maintain
interm ediate values. S o selection favors the preservation o f alleles
with additive effects, producing m ore intermediate phenotypes (like
the peas o f interm ediate height in the previous exam ple). Physical
size, or stature, is an example o f this; the average for a given species
generally has a biological advantage over either extreme. Another
example is the heterozygous condition for sickle-cell anemia. T h e
hom ozygous condition produces a genetic disease, bu t the heterozy­
gous condition confers a relative im m unity to m alaria. T h a t isn’t
im portan t in m odern technological society, but when slash-and-burn
agriculture was spreading through A frica there was probably selection
favoring the heterozygous condition. T h is example also points out
how com plex the interplay between heredity and environment can be.
M iele: L e t’s get back to intelligence an d mental ability. A s you said,
it’s obvious that a sim ple inheritance m od el based upon tw o alleles—
sm art and dull— ju st doesn’t fit.
Jensen: R ight. M o st o f the human traits o f greatest interest to psy­
chologists are not M endelian. Individual differences an d group dif­
ferences in these traits are not attributable to a single gene with two
alleles. T h e variation in these traits d oes n ot consist o f only two or
three discrete types, as in M endelian characters (like b lo o d type), but
o f continuous, quantitative gradation throughout the w hole range o f
variation, from the low est to the highest. T h e genetic underpinning
o f continuous or quantitative traits is polygenic, which only means that
more than one gene is involved in the trait variation. T h e number o f
genes for a polygenic trait may range anywhere from tw o genes on up
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into the hundreds. F o r m ost polygenic traits, the num ber o f genes is
not known, but there are ways theoretically to make a rough estimate
o f this number for a given trait.
M iele: S o how can genetic models deal with the h um an behavioral
traits you’ve just said were so complex?
Jensen: T h is problem was also solved by the British geneticist and
statistician Sir R on ald Fisher in one o f the landm ark papers in the
history o f genetics. “ T h e Correlation Between Relatives on the
Su p p osition o f M en delian Inheritance,” published in 19 18, laid the
foundation for quantitative genetics (the genetics o f continuous,
polygenic traits as contrasted with single-gene or M endelian traits).
Fisher proposed th at quantitative traits are determ ined by a whole
set o f genes (that is, they exhibit polygenic variation) and th at the alter­
nate alleles for each gene in the set slightly increase or slightly
decrease the observed phenotype fro m the population m ean o f that
trait, but the sim ple M endelian laws h old for each o f these genes. For
example, suppose that stem height was n ot the result o f just the two
alleles for one gene ( T and f, as in the m odel above), b u t three genes
with two alleles each: (S and s'), ( T and f), and ( U an d m). T h e alleles
S, T, and U each slightly increase stem height from the population
mean, while the alleles s, t, and u each slightly decrease it.
Given these explicit conditions and a set o f m athem atical form u­
las (known as “ M endelian algebra” ), Fish er calculated the theoretical
genetic correlation between any degree o f kinship (fo r example, par­
ent-child, identical tw ins, fraternal twins, siblings, first cousins, and
so on ) for any polygenic trait in any species o f hum ans, or any sexu­
ally reproducing plan ts or animals. T o take the sim p lest case, M Z
(th at is, m onozygotic or identical) tw ins share the exact same set o f
genes because they b o th develop from the division o f a single fertil­
ized egg. S o according to Fisher’s form ulas, their theoretical correla­
tion on any heritable, quantitative trait (such as heigh t or IQ ) is
+ 1.00, as it would be for any individual with themselves or with their
clone. T h e theoretical correlations fo r D Z (that is, dizygotic or fra­
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ternal twins, whether o f the same sex o r opposite sexes), parent-child,
and full siblings are all + 0 .5 0 because these kinships all share, on
average, h alf o f their genes. T he correlations predicted by Fishers
form ulas continue to decrease as the degree o f kinship decreases. For
unrelated individuals, the predicted correlation is 0 .0 0 , though this
w ould n ot hold for rem ote, small villages whose m em bers are all
related or in pure breeds o f dogs, thoroughbred h orses (who all
derived from a handful o f ancestors), laboratory m ice, or inbred
strains o f corn, rice, o r other plants.
T h o se are the theoretically predicted correlations based on ge­
netic similarity. T h e actu al correlations we find when we test pairs o f
M Z twins or D Z tw ins, or groups o f siblings, cousins, or unrelated
individuals, can vary continuously fro m —1.00 (that is, exact o p p o ­
sites— the higher one m em ber o f the p air scores or m easures, the
lower the other does) to 0 .0 0 (no greater resemblance in their scores
than between pairs o f ran d om num bers) to + 1 .0 0 (perfect parallel—
the higher one m em ber o f the pair scores or measures, the higher the
other does, as well).
Table 3.1 compares the predicted correlations fo r the various
degrees o f genetic sim ilarity against the actual correlations found by
behavioral genetic research.
M iele: A n d how do these figures help us to resolve the nature-nurture uncertainty?
Jensen: By comparing th em against the correlations we actually find
in behavior genetic stu d ies o f mental ability and other psychological
traits to see how well they fit. It turn s out that they closely fit the
genetic predictions an d d o not fit predictions we w ould m ake from a
purely environmental theory. There is n o valid environmental expla­
nation, fo r example, fo r why identical tw ins reared a p art should be
alm ost as alike as identical twins reared together and m uch more alike
than fraternal twins o r ordinary siblings reared together; or, on the
other hand, why unrelated adopted children reared together should be
so unlike. There are all so rts o f statistical tests you can use to validate
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BOTH?
T A B L E 3.1 Predicted and Actual Correlations in IQ for Various
Degrees o f Kinship
Predicted:
Actual:
Identical (MZ) twins reared together
(Sam e genes in same home environment)
1.00
0.86*
Identical (MZ) twins reared apart
(Sam e genes in different home environments)
1.00
0.78*
Fraternal (DZ) twins reared together
(50% same genes in same home environment)
0.50
0.60*
Full siblings reared together
(50% same genes in same home environment)
0.50
0.47*
Full siblings reared apart
(50% same genes in different home environments)
0.50
0.24*
Natural parent-child in same home
(50% same genes in same home environment)
0.50
0.42*
Natural parent-child adopted by other home
(50% same genes in different home environments)
0.50
0.24*
Adopted siblings reared together
(Different genes in same home environment)
0.00
0 .3 2 |
Parent-adopted child
(Different genes in same home environment)
0.00
0.19 f
Degree o f Kinship
*
These correlations, which contain a genetic factor, increase with
age.
|
These correlations, which contain only an environmental factor,
decrease with age.
The predicted correlations are those derived from the
simplest genetic model and taken from: "How Much Can
We Boost IQ and Scholastic Achievement?" Harvard educational review
39, Winter 1969, p. 49. The actual correlations are those summarized
from various sources and reported in Robert Plomin, et al., Behavioral
genetics (4th edition), (New York: Worth Publishers, 2000).
so u r c es:
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the genetic model, but I’ve given you the big picture. T h e genetic
m odel, which also takes account o f environmental factors, fits the
observed facts, while a purely environmental m odel fails.
M iele: S o then is the best estimate o f the heritability o f intelligence
the average o f all these studies, about 0 .6 0 ?
Jensen: N o , not really, because the average estimate o f heritability is
based on the com bined heritability estim ates o f I Q for every age
group, and it is now known that the heritability o f I Q increases with
age, goin g from about 0 .3 0 in very early childhood to about 0 .7 0 in
early m aturity and up to about 0 .8 0 in later maturity. T h e older we
becom e, the more the phenotype reflects the genotype. A strictly
environmental theory w ould predict ju st the opposite, so the increase
in the heritability o f I Q with age is another case where the genetic
m odel fits the facts and the purely environmental m odel fails.
W h en we talk abo u t a best estim ate o f heritability, we have to
specify an age group. Various mental tests do not yield equivalent her­
itability estimates, either. Virtually all I Q tests are highly g loaded, but
som e are purer m easures o f g than others. Generally, the m ore a men­
tal test measures the g factor, the higher is its heritability. T h is fact
also provides evidence for the biological, rather than merely statisti­
cal, reality o f g.
M iele: S o how do we best estimate the heritability o f I Q , and what
is its value?
Jensen: From studies o f identical tw ins reared apart. In all the pub­
lished studies o f pairs o f M Z twins separated in infancy, p u t out for
ad op tion , and reared entirely apart, the average correlation between
the I Q s o f the twins in adulthood is 0 .7 5 . Since the twins did not
share a com m on environm ent but d o have identical genes, this cor­
relation provides a fair estimate o f the heritability o f I Q fo r people
in the norm al range o f environments for our population . At the
other extreme from M Z twins reared apart are unrelated adopted
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children who are reared together like full siblings. In early ch ildh ood
their IQ s correlate about 0 .2 5 , b u t by late adolescence the co rrela­
tio n drops to nearly zero. T h is show s that the shared environment in
which they b o th were reared h as virtually no lastin g effect on their
I Q s. T h e IQ s o f full siblings reared together, however, correlate
a b o u t 0.47, w hich is close to th e ir theoretically expected genetic co r­
relation o f + 0 .5 0 .
M iele: D on’t these figures show that environmental factors are also
im portant?
Jensen: Yes, bu t the most pow erful environmental effects are n ot p a rt
o f the shared fam ily environment. These effects occur within fam i­
lies, not between families, an d m ake up what is often referred to as
the “ nonshared environment.” I prefer to call it “ nongenetic,” because
I believe it has m uch less to d o w ith the psychological or social envi­
ronm ent than w ith what I call the “biological microenvironment.” It
consists o f all environmental effects that have biological co n se­
quences, particularly on the neural basis o f m ental development,
beginning at conception. T h e y are largely accidental or random. E ach
single effect is usually too sm all to be detected, bu t i f they accum u­
late over the course o f developm ent from conception to m aturity
they can becom e evident.
T h ese microenvironmental effects may contribute as much as 2 0
or 2 5 percent o f the total variance in IQ in the population. Because
they are more o r less random, th ey are difficult to remedy or control.
T h e ir occurrence has probably been reduced in recent decades by
improved nutrition o f m others an d children, advances in obstetrical
techniques, inoculation against th e common ch ildh ood diseases, and
im proved health care in general. M o st o f the population in T h ird W orld countries and in som e sm all subpopulations in the U n ite d
States and other industrialized countries have n o t had the benefits o f
these nutritional and health-care measures, and th is probably affects
their mean I Q . T h e reduced occurrence o f
these unfavorable
microenvironm ental elements in the industrialized countries is p ro b ­
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ably one o f the causes o f the gradual rise in mental test scores in
these countries during the last 6 0 or 7 0 years.
Miele: In theory, identical twins share 1 0 0 percent o f their genes. We
can usually tell they’re identical just by lookin g at them. So the physi­
cal traits are largely genetic. But doesn’t the fact that they look so much
alike also mean that they’re treated more alike by their parents, by
schoolteachers, by society at large? Doesn’t the self-fulfilling prophecy
factor confuse the effects o f heredity with th ose o f environment?
Jensen: T h ere is no evidence at all that p eop le looking alike makes
their IQ s m ore alike. D izygotic (D Z ) or fraternal twins are geneti­
cally no m ore alike than ordinary siblings; their genetic correlation is
0.5 0 . However, like other siblings, som e sam e-sex D Z tw ins look
much more alike than others. In some cases their parents even wrongly
believe that their D Z twins are identical tw ins, and they treat them as
such by dressing them alike and giving them the same hairstyles, and
so on. But D Z twins whose parents and others h ad mistaken them for
M Z twins are no more alike in I Q than oth er D Z twins or ordinary
siblings who d on ’t look much alike.
I f those who really believe that the I Q correlation between M Z
twins is better explained in term s o f their physical similarity than in
term s o f their genetic correlation, they sh o u ld go out and fin d unre­
lated people who look alike, such as movie stars and their doubles,
and determ ine the correlation between their IQ s. T h a t would p u t this
theory to the acid test. T h e safest bet im aginable would be th at the
correlation com es much closer to the correlation between pairs o f
people picked at random (th at is, about 0 ) fro m the general p o p u la­
tion than the correlation between M Z tw ins reared apart (th at is,
about 0 .7 5 ). O f all the failed attem pts I ’ve ever heard to explain away
the im portance o f genetics in individual differences in intelligence,
the look-alike theory is the m o st absurd.
Miele: S om e o f the studies o f identical tw ins reared apart th at you
and other hereditarians use to estimate the heritability o f I Q were
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OR B O T H ?
conducted by the fam ous British psychologist S ir Cyril Burt. A num ­
ber o f scholars carefully scrutinized Burt’s publish ed research. T h e y
questioned how the correlations between twins changed so little even
though Burt claim ed that he had added new sets o f twins to his d ata­
base and concluded that Burt ju st “ made u p ” the correlations. D id
you ever question B u rt’s twin studies? D o you th ink he
faked
his
twin data? H asn ’t the Burt A ffair cast a shadow over twin studies?
Jensen: Because o f these suspicions, Burt’s twin correlations are no
longer cited in any summaries or discussions o f the heritability o f
IQ . Two extremely thorough independent investigations o f the accu­
sations against Burt, however, have found these claim s o f faked or
fraudulent data to be wholly unsubstantiated. T o the best o f our
knowledge, the charges against B urt are false. F o r a tim e they seem ed
plausible because there are a considerable number o f numerical errors
in Burt’s later published reports. Virtually all o f B u rt’s errors are in
articles he published when he was in his late 7 0 s and 8 0 s (he died at
age 8 8 ) and are probably inadvertent, careless errors because abo u t
the same rate o f numerical errors, things like tran sposed page num ­
bers and the like, occur in the reference citations in his articles.
Miele: So that lets Burt o f f the hook? How about the way the corre­
lations remain so constant, even though the articles show different
numbers o f twins were examined?
Jensen: T h e fact that the M Z twin correlation was 0 .7 7 in three d if­
ferent reports is n ot too surprising for cumulated, overlapping data
sets. Burt’s value o f 0 .7 7 is very close to our best estimate for this
correlation. A num ber o f other studies o f M Z tw ins reared apart
have reported correlations o f 0 .7 6 and 0.78, and no one claims th ose
studies were “ faked” or the num bers were “ cooked.”
N o one with any statistical sophistication, an d Burt had plenty,
w ould report exactly the sam e correlation, 0 .7 7 , three times in su c­
cession i f he were trying to fake the data. O ne n o ted scientist laugh ­
ingly told me that when he and his colleagues fo u n d a correlation o f
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0 .7 8 for the IQ s o f M Z tw ins reared apart, they were grateful as hell
that the correlation d id n t tu rn out to be 0 .7 7 ! In view o f these recent
findings, i f Burt did fake his data, we’d have to credit him with clair­
voyance.
D uring B u rts long and influential bu t controversial career, he
seemed to have made m ore enemies than friends, and I believe that
was probably p art o f his problem . H is autocratic and egocentric per­
sonality hardly endeared him to people. H is m ost vociferous detrac­
tors included both those who disliked him personally and th ose who
disliked the idea that hum an mental ability is so highly heritable as
Burt had claimed. However com forting it seem ed for B u rt’s o p p o ­
nents to suggest, and perhaps even believe, that Burt “ co o k ed ” his
data, more recent research has proved B u rt to be correct and his
detractors flatly wrong. O n e com m entator likened the latest phase o f
the nature-nurture I Q
debate to “ a stom pin g m atch between
G odzilla [that is, genes] and Bam bi [that is, environment].” M u ch has
been written about the B urt scandal for th ose who may be interested
in the details.
Miele: Leon Kamin, one o f the principal critics o f B u rt’s work,
yours, and hereditarian research in general, once claimed that you
only adm itted that Burt’s tw in correlations were faked— an adm is­
sion you’ve now told us yo u ’ve taken back— and took credit for find­
ing the fraud, after he [K am in] called you on it in a debate. T h a t’s a
pretty serious challenge to your scientific integrity and com petence!
Any comment?
Jensen: H ere are the details. Y ou decide.
After Burt died, I went to Lon don and obtained from B u rt’s sec­
retary reprints o f all o f the papers Burt ever wrote on twins an d other
kinships in his studies o f the heritability o f IQ . As these were scat­
tered in many different journ als, I thought it would be o f value to
behavioral geneticists to have all o f Burt’s d ata sum m arized in a sin­
gle article. In preparing this article, which consisted o f listin g Burt’s
correlation data for each type o f kinship in separate tables, the
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numerical errors in his reports became clearly apparent; I fo u n d some
2 0 such errors, including the three correlations o f 0 .7 7 or 0 .7 7 1 that
Kam in suspected were fraudulent because they all had the sam e value.
I wrote a detailed article on Burt’s errors and subm itted it to the
British Journal of Psychology. A fter a long delay, they rejected it an d I sub­
m itted it to Behavior Genetics, which published it the sam e year that
Kamin’s b o ok came out. W hen I learned that Kamin, in an address
given I believe at a m eeting o f the Eastern Psychological A ssociation,
had m entioned three o f Burt’s errors as the basis o f his claim o f
fraud, I credited Kam in fo r this observation in a footnote in my paper
in Behavior Genetics.
I f I have behaved in any way dishonorably with respect to the Burt
affair, I’d like to know ju st how. I f anything, I was too quick to come
to accept that Burt’s d ata were “ cooked” based on the inform ation
given in Hearnshaw ’s biography. W hen further, more careful investi­
gations revealed the lack o f any solid evidence o f fraud. I, o f course,
reversed my opinion.
M iele; Returning to the science involved, why doesn’t your estimate
o f the heritability o f intelligence o f abo u t 0 .7 6 agree w ith the esti­
mate o f about 0 .50 that appeared in the prestigious British journal
Nature? Surely that isn’t a case o f m edia bias. It still indicates a sig­
nificant genetic factor, bu t it’s substantially lower than the figure o f
0.75 to 0 .7 6 that you an d other hereditarians keep repeating. And
there are also arguments that the only really conclusive estim ate o f
the heritability o f intelligence comes n ot from T h o m as Bouchard’s
M innesota Twin Project or the other sim ilar studies b u t from the
work o f geneticists C . R . R ao and N ew ton M orton . It used a
m ethod known as path analysis, which the authors say is the only way
to take cultural factors properly into account. So who’s right?
Jensen: Setting up a genetic m odel that encom passes all o f the vari­
ous degrees o f kinships on which there exists suitable I Q data always
involves certain assum ptions. D ifferent m odels that use different
assum ptions result in somewhat different estimates. T h e more
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detailed and fine grain ed the m odel, the more equations and assum p­
tions it requires. T h e technical disagreements largely concern these
assum ptions, rather than the actual data per se.
T h e analysis in Nature that you m entioned hypothesizes a maternal
effect that would m ake M Z twins m ore alike because they share the
m oth ers womb d uring the nine m onths o f pregnancy. Since it is an
environmental, n o t genetic, effect, it reduces the estim ate o f heritability. But other behavior geneticists argue that m o st o f what hap­
pens during pregnancy makes twins more different, rather than more
alike, and thus causes us to underestimate the true heritability.
But even if the heritability o f I Q is 0 .5 0 rather than 0 .7 8 (o r 0.70,
0 .7 5 , or 0.77), it still shows that there is a significant genetic com ­
pon en t to individual differences in mental ability. T h a t is a far cry
fro m saying that I Q differences are largely the result o f social, eco­
nom ic, and cultural factors.
M iele: But som e critics question whether twins provide a fair repre­
sentation o f the entire population. D o n ’t you need other evidence?
Jensen: Yes, and fu rth er incontrovertible evidence com es from look ­
ing at the other sid e o f the coin. A dop tion studies allow us to com ­
pare genetically unrelated children who have been reared together
from infancy against full siblings reared together. A n d adoption stud­
ies require fewer assum ptions than any other m eth od o f estimating
the effects o f genetic factors and shared family environment on IQ .
T h e I Q correlation between unrelated children reared together
decreases with age, going from about 0 .3 0 in early childhood to
alm ost zero in late adolescence, showing that the effect on I Q o f
being reared together in the same fam ily is virtually washed out by the
tim e people reach maturity.
T h e Texas A d o p tio n Project with 3 0 0 adoptees, conducted by a
team o f behavioral geneticists at the University o f Texas, is the largest
data bank o f this k in d and has the highest quality o f data, with IQ s
o f all family m em bers. A path m odel analysis o f these data, consist­
ing o f IQ s for the m other, father, their biological offspring, and the
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adoptees, was recently perform ed by the Texas team when the adopted
children had an average age o f 17 years. T h e population value o f the
heritability derived fro m these data is 0 .7 8 , which is n ot significant­
ly different from the heritability o f 0 .7 5 estim ated from the correla­
tion between M Z tw ins reared apart or even Sir Cyril B u rt’s alleged­
ly “ co ok ed ” heritability o f 0.77! T h e strong agreement between the
two m o st direct lines o f evidence— identical twins reared apart and
unrelated children reared together— provides the best estim ate we
now have o f I Q heritability.
T h e m o st im portant and unarguable p oin t in all o f these studies
is that no one has been able to explain the pattern o f the various kin­
ship correlations w ithout recognizing the substantial effect o f ge­
netic factors. I f it could have been done, it certainly w ould have been
done by now, because many technically competent scientists have
tried. Even i f heredity turn s out to be K in g Kong and n o t Godzilla,
would that make you switch your bet to Bam bi in the hypothetical
stom pin g match?
Miele: Well, the H u m an Genom e Project is in the process o f trying
to m ap every human gene. T h at should provide the m o st direct evi­
dence imaginable. S o far, the Project has identified the specific genes
for various diseases, including m ental and behavioral ones like
A lzheim er’s. But no one has found a gene for intelligence. I f the her­
itability estimates are accurate as you claim they are, shouldn ’t find­
ing the I Q genes be relatively easy? A fter all, your theory says that
there are many genes th at contribute to IQ . W hy hasn’t anyone stum­
bled on to at least one o f them?
Jensen: O ne doesn’t m erely stumble on to these things. O n e has to
search fo r them. But yo u ’re wrong. A t least four genes o r D N A seg­
ments that affect I Q have been identified by behavior geneticist
R obert Plom in o f the Institute o f Psychiatry o f the University o f
Lon don . A nd his investigation continues. T h ese experim ents have to
be replicated at least tw o or three tim es to rule out chance findings,
and the genes identified have held up in repeated studies.
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T h e method P lom in uses is know n as quantitative trait loci, or
Q T L . W hat he and his research team d o is to get tw o groups o f sub­
jects, one group with average IQ s an d another grou p with very high
IQ s. U sin g blood sam ples from these two groups, they extract D N A
and examine a strand o f D N A from a particular chrom osom e (in this
case, chrom osom e num ber 6 ) and search for a significant difference
in the D N A between the average an d high IQ grou ps. A significant
difference in the D N A could be a marker o f one o f the genes that
influence IQ . T h e research team then has to look at the same D N A
in a new set o f average and high I Q group s to see i f the same signif­
icant difference in D N A shows up. T o rule out any “ chance” effect,
you have to repeat the study with new groups. It is certainly not easy
to d o this research, as you seem to believe it should be. It is extremely
laborious and painstaking, but is gettin g somewhat easier as the tech­
n ology o f m olecular genetics develops more efficient methods o f
D N A analysis.
A n d because intelligence is polygenic, each gene contributes only a
sm all part o f the to tal variation in IQ . T h e first few genes discovered,
for example, account for only about 3 or 4 percent o f the total I Q
variance. T he genes w ith the largest effects will m o st likely be found
first. T h e task o f findin g the next ones will probably become more
difficult, because each one’s effect will likely be sm aller than that o f
those found earlier in the search. F ro m all the evidence o f the high
heritability of I Q , however, we know that genes are involved. But
finding the specific genes is m uch like looking fo r needles in a
haystack, even when you know for sure that there actually are needles
in the haystack.
M iele: Then if it’s so difficult to lo o k for the specific genes, why
both er i f we already know from heritability studies th at I Q is partly
genetic?
Jensen: F or the sam e reason that geneticists lo o k fo r the specific
genes for, say, a particular form
o f cancer, or for a type o f
A lzheim er’s disease, or H untington’s chorea, or Tay-Sachs disease,
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cystic fibrosis, m uscular dystrophy, and many other genetic co n d i­
tions. Identifying the gene or genes is the first step in uncovering the
processes by which some individuals develop lower or higher IQ s
than others. M erely knowing that something is genetic doesn’t explain
much o f anything; it only tells us where to lo o k fo r the explanation,
or at least som e p art o f it. A g o o d example is a type o f m ental retar­
dation known as phenylketonuria, or PKU, which we now know is
caused by a double recessive gene. Possession o f this particular gene
was found to result in a failure to m etabolize properly a certain p ro ­
tein. T h is faulty m etabolism yields biochemical products that dam age
the growing brain, thereby retarding mental development. Elim inating
this protein (phenylalanine) fro m the diet, in fact, usually allows
m ental growth to proceed fairly normally. W e want to discover the
chemical m odus operandi fo r the m ost influential genes th at are
involved in hum an intelligence.
A t the same time, neuroscientists are directly studying the brain
structures and the neural and m etabolic processes that underlie intel­
ligence. For a com plete understanding, we have to explore in both
directions, from the genes and fro m the brain. Like digging a tunnel,
you excavate from both ends. T h a t’s how I see the advancement o f
our knowledge o f the physical basis o f intelligence as taking place.
M iele: Is there anything to be gained by more heritability stu dies o f
the W hites in N o rth America an d Europe? W h a t about other grou ps,
especially Blacks? C an heritability studies ever tell us anything abo u t
the cause o f the Black-W hite difference in average IQ?
Jensen: By now, heritability studies o f g in W h ite populations have
probably reached the point o f diminishing returns. There have been
a few studies o f I Q heritability in the Black population and there
seems to be no statistically significant difference fro m the W h ite her­
itability o f IQ . But the heritability within each group alone tells us
virtually nothing about whether the average difference between the
groups is heritable. I f the grou p means differ markedly, and i f the
heritability o f I Q within each g ro u p is very high, and if the environ-
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mental factors known to affect I Q do not d iffer very much between
the groups, it w ould be surprising i f the g ro u p s did not actually dif­
fer genetically to som e extent. But such evidence by itself is in suffi­
cient to su p p o rt any serious argument on this point. O ther lines o f
evidence are needed for studying the causes o f the observed average
I Q difference between different racial p opulation s. I have discussed
this whole issue in considerable detail in my b o o k The g Factor.
M iele: T hen let’s take it up in the next chapter.
Further Reading
F o r excellent in troductions and sum m aries by experts in behavior genetics and psycho­
m etrics, see: Plom in, R ., and M cC learn, G . (E ds.) ( 1 9 9 3 ) . Nature, nurture, and psychology.
W ashington, D C : A m erican Psychological Association; an d Rowe, D. C. ( 1 9 9 4 ) . The lim­
its of family influence: Genes, experience, and behavior. New York: G uilford Press. Contributions
by Jensen and other hereditarians and nonhereditarians, an d cognitive psychologist Earl
H u n ts concluding essay (the source o f the “ Godzilla versus Bambi” one-liner), are in:
Sternberg, R . J., and Grigorenko, E. (E d s .) (1 9 9 7 ). Intelligence, heredity, and environment. New
York: Cambridge U niversity Press. Generally more environmentalist contributions appear
in: Sternberg, R . ( 1 9 9 7 ) . Special issue: Intelligence an d lifelong learning. American
Psychologist, 5 2 (1 0 ), 1 0 2 5 —1 168. An overview o f the last tw o and other related publica­
tion s can be found in: M iele, F. (1 9 9 7 ). I Q in review: G ettin g at the hyphen in the naturenurture debate. Skeptic, 5 (4 ), 9 1 - 9 5 .
T h e kinship correlations predicted by genetic theory are reported in: Jensen, A. R.
(1 9 6 9 ). H ow much can we boost I Q and scholastic achievement? Harvard Educational Review,
3 9 (W inter), I —1 2 3 . T h e actual correlations found by researchers are ad apted from:
Plom in, R., et al. ( 2 0 0 0 ) . Behavioral genetics. (4th ed.) N ew Y ork: W orth Publishers.
T h e evidence o f m ed ia bias on the ra ce -IQ issue cited by Jensen is in: Snyderm an, M.,
and Rothman, S. ( 1 9 8 7 ) . Survey o f expert opinion on intelligence and aptitude tests.
American Psychologist, 4 2 , 1 3 7 —144; and their 1988 follow -up book, Snyderman, M ., and
R othm an, S. (1 9 8 8 ). The I Q controversy: The media and public policy. New Brunswick, NJ:
Transaction. W hen I interviewed R o b ert Sternberg, he also faulted the m edia, but for a
different reason— giving unwarranted attention to H errn stein and M u rrays hereditarian
best-seller The Bell Curve. See: Miele, F. (1 9 9 5 ). Robert Stern berg on “T h e bell curve.”
Skeptic, 3 (3), 72—80.
Perhaps the earliest an d harshest b o o k attacking the credibility o f Sir C yril Burt and
his research on twins an d the inheritance o f mental ability is: Kam in, L. J. ( 1 9 7 4 ) . The sci­
NATURE,
NURTURE,
OR
BOTH?
107
ence and politics of I. Q Potomac, M D : E rlb au m .T h e biography o f Burt that also concluded
that he had “ cooked” his numbers is: Hearnshaw, L. ( 1 9 7 1 ). Cyril Burt: psychologist. N ew
York: R an dom H o u se. Countering this view, Fletcher, R . ( 1 9 9 1), Science, ideology, and the
media, N ew Brunswick, N J: Transaction; and Joynson, R . B. (1 9 8 9 ), The Burt affair, London:
Routledge, dism issed the charges against Burt as “ n ot proven” (Joynson) o r “ false”
(Fletcher). For Jensen’s own retrospective on the Burt A ffair, see: Jensen, A. R . (1 9 9 2 ).
Scientific fraud o r false accusations? T h e case o f Cyril Burt. In Miller, D. J., an d Hersen,
M . (E ds.), Research fra u d in the behavioral and biomedical sciences, 9 7 —124. New York: Wiley. A
num ber o f pro and con essays can be found in: M ackintosh, N . J. (E d .) (1 9 9 5 ). Cyril Burt:
Fraud or framed? O xford: O xford U niversity Press. T h is b o o k includes an essay by Jensen
(B u rt was fram ed) and one by Jensens late mentor H an s J. Eysenck, who also knew Burt
very well (Burt’s research was a fraud).
F or more on Jensen’s work, see the bibliography o f his publications in A ppen dix A.
4
WHAT IS R A C E ?
Biological Reality
or Cultural Construction?
J
ensens 1 9 6 9 Harvard Educational Review article probably w ould have set
o f f little or no controversy i f he had m ade only two p o in ts (the fail­
ure o f com pensatory education, and the role played by the genes in IQ ),
and the word “Jensenism ” m igh t never have been uttered were it n ot for the
third com ponent— race. T h a t one four-letter word has bedeviled not just
American history but also the social sciences from their beginning. In the
m inds o f many, it is inextricably linked with a record o f violence, slavery,
prejudice, hatred, and all th at we hope not to be.
W hen I ask him why he to o k up so controversial a to p ic in the first
place, Jensen replies that the Black-W hite difference in average I Q was the
big question in education at th at time. So it was only natural th at an edu­
cational psychologist try to answer it using I Q tests. Further, he insists that
race has never been his m ain interest. H is research has been directed at
understanding the nature o f m ental ability. A t the time o f the H ER article,
he, like m ost social scientists, believed that test scores simply m easured bits
o f knowledge or skills acquired in W hite, m iddle-class hom es and schools.
A s he probed deeper into the nature o f m ental ability, he began develop­
ing tests o f reaction time an d sim ple decision m aking instead o f I Q tests,
and applying genetic m eth ods to study b o th individual differences and
group differences.
109
no
IN TE LLIG E N C E ,
RACE,
AND G E N E T IC S
I then ask how he, an educational psychologist, defines the word “ race”
and responds to an official statem ent by the A m erican A nthropological
A ssociation (A A A ) th at “the concept o f race is a so cial and cultural con­
stru ctio n ” that
“ sim p ly cannot be tested or proven scientifically.”
A ccording to the A A A statement, “ it is clear that hum an populations are
n ot unam biguous, clearly demarcated, biologically distinct groups,” and
therefore “the con cep t o f ‘race’ has no validity . . . in the human species.”
T h e cultural constructionist view opposes the con cept o f race both for
presum ing to establish fixed categories out o f the flu x o f nature an d for
any further tendency to attach racial stereotypes to th ose categories once
they are established. A ccording to the constructionist position, the carving
u p o f the continuum o f human variation into races is not a scientifically
valid pursuit but an arbitrary activity constrained by cultural conditioning.
Ju st how many races one distinguishes, and where an d how one draws the
boundaries between races, depend on on e’s purposes. Further, cultural con ­
structionists believe, the use o f what m ay be insignificant physical features
as criteria for classifying people into distinct, fixed categories encourages
the faulty assum ption that particular, shared physical traits are accom pa­
nied by particular, shared mental abilities and behavioral attributes, and
that the categories can be ranked accordingly.
Jensen responds by giving two definitions o f “ race ” that, he says, d if­
fer only in the perspective that they take. In the taxonom ic definition,
races are subspecies o r varieties o f a species that d iffe r in their physical
characteristics and m ay also differ in their behavior. T h e concept app lies
to anim als and p lan ts as well as to hum ans, and no qualitative ranking is
im plied. For exam ple, the w olf species, Canis lupus, includes various su b ­
species typically fo u n d in different p a rts o f N o rth A m erica, Europe, and
A sia. In the secon d definition, which comes fro m pop u lation genetics,
subspecies or races are breeding p o p u latio n s that d iffe r in the frequen­
cies o f one or m ore genes. It is these genetic differences that produce the
physical and even so m e o f the behavioral differences am ong animal su b ­
species. Jensen d ism isse s the A m erican A n th ropological A sso ciatio n s
characterization o f “ race.” N eith er o f the defin itions he offers assum e
the existence o f the “ unam biguous, clearly dem arcated, biologically d is­
tinct g ro u p s” d escrib ed in the A A A caricature. B ecause subspecies or
WHAT
IS
Ill
RACE?
races can and do interbreed, Jensen says, they are by definition
fu zzy
sets” — that is, they lack the d istin ct boundaries th at demarcate species,
and in stead show a continuous blen din g o f characteristics. H e argues
that m od ern D N A studies generally confirm the traditio n al racial classi­
fication schemes o f an th ropologists as well as o f the m an on the street,
although many hum an geneticists u se the more neutral term “ p o p u la ­
tion ” instead o f the em otionally laden “ race.”
O f course, the flash point is the linkage o f “ race” with “genes” and
“ intelligence.” Jensen’s research and the race-IQ debate in general have cen­
tered around Black-W hite difference in average I Q because m ost o f the
relevant research has focused on these groups and because the race issue
has lon g been seen as America’s m ajo r social problem . Jensen presents the
data an d analyses th at he believes su p p o rt what he term s his D e fa u lt
H ypo th esis regarding racial differences in the g facto r (that is, in general
intelligence):
•
T h e causes and consequences o f race differences in intelli­
gence are the same as the causes and consequences o f indi­
vidual differences within either group— bo th environmental
and genetic factors are involved, and the im portance o f the
genetic factor is no different for Blacks than for W hites.
•
There is no evidence for so m e special cultural factor (such as
the legacy o f slavery) that lowers the average I Q scores o f
•
Blacks.
Therefore, b o th the difference in adult socioeconom ic sta­
tus (S E S ) between m em bers o f the same race and the d if­
ference in average S E S between Blacks and W hites are
causally related to differences in the^ factor. But genetic d if­
ferences in the g factor are a more significant cause o f d if­
ferences in adult S E S than are differences in childhood S E S
o f differences in g.
W h en I challenge Jensen to su p p o rt these b o ld assertions, he presents
three lines o f evidence and reasoning that he believes favor the D e fau lt
H ypoth esis against any nongenetic, culture-only hypotheses:
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INTELLIGENCE,
•
RACE, A N D
GENETICS
First, when culture-only explanations have been tested, they
have been disproved.
• Secon d, evolution tells us that i f subspecies, or races, have
physical differences, they have som e behavioral differences as
well.
•
Finally, Jensens research has confirm ed Spearm ans observa­
tion that the more a test measures the g factor, the greater the
Black-W hite difference on that test. Both the g factor and
Black-W hite differences correlate w ith direct biological and
physiological measures, including heritabilities, inbreeding
depression, gains produced by outbreeding, and the size,
electrical activity, and glucose m etab olism o f the brain.
I cross-exam ine Jensen on each o f his three lines o f evidence, starting
with ten o f the best-known culture-only theories that many social scien­
tists say disprove his D efault H ypothesis. W e end with the repo rt o f a spe­
cial com m ittee appointed by the American Psychological A ssociation to
look into the race-IQ question, which concluded that “there is certainly no
such su p p o rt for a genetic interpretation” o f the Black-W hite difference in
average IQ .
Miele: Please don’t tell me that race isn’t a controversial topic. Even
am ong experts it’s a four-letter word, and am on g ordinary citizens it’s
best avoided. D iscussion o f race can end friendships, derail careers,
or set o f f riots, as well you know from your own personal experience!
Jensen: R ace isn’t just a controversial to p ic— it is the most controver­
sial topic. In academic circles, race differences in mental ability are
the m ost tabooed research subject. T h e only runner-up— at a great
distance behind in this respect— is the to p ic o f sex differences in
behavioral traits.
Miele: W h y then did an educational p sych ologist interested in how
we learn, how everyone learns, get involved in the race issue? In ret­
rospect, wouldn't you have done better to have stuck to the concept
WHAT
IS R A C E ?
113
o f general intelligence, the evidence for genetic factors w ithin groups,
and ju st bypassed the whole race-IQ issue by saying th at it can’t be
resolved? Instead, you’ve had to spend your last 3 0 years contesting
this issue?
Jensen: Well, there are two points here.
First, the big question in education has long been conspicuous—
why do Black children, on average, have quite m arkedly lower
scholastic achievement as com pared with any other racial or ethnic
group in the U.S. popu lation ? T h e pop u lar m edia have devoted con­
siderable attention to this question for the last 3 0 years. It has been
the subject o f presidential com m issions and countless discussions
am ong school officials, from the federal to the local level. N ow
w ouldn’t it seem strange i f a psychologist, especially an educational
psychologist, didn’t ask h im self that question? A nd even stranger if
he didn’t then try to find the answer, using the to ols o f his profes­
sion, namely, em pirical research based on psychom etric and statisti­
cal m ethods?
W h en I got into this area, all inform ed persons knew that both
individual differences and racial group differences in scholastic
achievement could be predicted by IQ . A nd we had lon g known o f
the average Black-W hite difference o f about 15 poin ts in I Q , based
on nationwide norm s. S o naturally one w ould suspect th at the BlackW hite I Q difference is probably an im portan t factor in Blacks’ aver­
age shortfall in scholastic performance. A nd since various causal the­
ories o f the Black-W hite I Q difference, often contradictory theories,
were being propounded, wasn’t it logical to ask which theories were
valid and which were not, in light o f whatever em pirical evidence
could be sought on this question? Well, that pretty m uch summarizes
my thoughts and my m otivation regarding these questions over 30
years ago when I was teaching educational psychology in Berkeley.
T h e y are questions that were then, and still are, o f great national con­
cern, n ot just academ ic curiosity.
M iele: A nd your secon d point?
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INTELLIGENCE,
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GENETICS
Jensen: I haven’t spent 3 0 years researching only the race question. I’ve
never lost interest or run away from it, but my prim ary interest was
and is the more basic question o f the nature o f m ental ability itse lf
and the causes o f individual differences. It was these questions, more
than the race question, that led me first into behavioral genetics and
then experimental cognitive psychology. I have devoted two decades
to research on m ental chronometry, using reaction tim e to measure
speed o f processing inform ation by individuals o f different I Q lev­
els.
M iele: W hy is that im portant?
Jensen: Because the peop le who studied the race question a genera­
tion or so ago didn’t realize that underlying the race question were
m ore fundamental psychological and psychometric questions. T h ere’s
the question o f cultural bias in m ental tests, whether test scores
reflect anything other than bits o f knowledge or skills that could be
acquired by children brought up in a W hite, m iddle-class cultural
environment— the kin d o f environment that affords the opportunity
to learn the kinds o f knowledge that mental tests are devised to
measure. I f racial differences are n ot explainable in term s o f test bias,
other explanations m u st be considered, including biological and
genetic causes. I researched these questions in depth and stated my
conclusions in my 1 9 8 0 book Bias in Mental Testing.
It is my position, b ased on the available research, that racial group
differences in g are essentially no different from individual differences
with respect to their causes and consequences. I see average group d if­
ferences simply as aggregated individual differences. T h is is the best
conclusion I have been able to reach so far, but I am not dogm atic
about it. I am still researching this aspect o f group differences.
M iele: R ace was certainly the organizing concept o f nineteenth-cen­
tury anthropology, bu t it’s hardly even mentioned these days. Many,
including the experts, say race is, n ot a biological reality, but a mere
cultural construction in which a few insignificant physical features are
WHAT
IS R A C E ?
115
seized upon, for some nefarious purpose, to classify people into dis­
tinct, fixed categories, all o f whose m em bers supposedly share not
only physical bu t behavioral characteristics as well. So, before we go
any further, what is your definition o f race?
Jensen: T h ere are two definitions o f race. T h e y are simply different
ways o f viewing the concept, and both o f th em are com pletely com ­
patible.
First, in biological taxonomy, a given species typically has a num ­
ber o f distinguishable subspecies or varieties. In the human species,
Homo sapiens, the subspecies are called “races.” Species are highly and
clearly differentiated in a large number o f physical and even behav­
ioral characteristics, and different species
are not interfertile,
although in very rare cases m atings between certain closely related
species can produce offspring. Therefore, one does not see blending,
or continuous intermediate gradations o f physical characteristics,
between different species. W ith in any species, however, there are sub­
species that are truly interfertile, and their o ffsp rin g show a blending
o f the characteristics o f b o th subspecies.
In the course o f evolution, subspecies or races have developed as a
result o f genetic isolation an d natural selection. T h e isolation o f one
group from another occurs because o f m igratio n o f som e p a rt o f a
population to another location, and because o f natural barriers to
interm ingling o f populations, such as m ountain ranges, deserts,
oceans, and the like. For hum ans, isolation m ay also occur because o f
m an-made social barriers to the intermixing o f groups, such as reli­
gious prohibitions and caste systems. N a tu ra l selection occurred
because different environments made different demands on relatively
isolated g rou p s as they struggled to survive. Certain traits favor sur­
vival under one environment, and other traits favor survival in other
environments. There is natural selection for the traits that favor sur­
vival in each specific environment.
There is also the effect known as “genetic drift,” which refers to the
fact that any relatively sm all subgroup random ly selected fro m its par­
ent population will not have exactly the sam e gene frequencies as the
116
INTELLIGENCE,
RACE,
AND
GEN ETIC S
parent population. S o if this subgrou p migrates to a new geographic
location, it will differ to some degree from its parent population, and
these genetic differences will be p assed on to its descendants.
A ll these forces act together to produce the anatom ical, bioch em ­
ical, and behavioral differences th at allow us to distinguish subspecies
within a species, which in the case o f our own species, Homo sapiens
we term “ races.” Because isolation o f groups is n o t 100 percent and
because races are interfertile, they are not distinct categories, or pure
types, as exist in other species. R ace s have been called “ fuzzy se ts”
because, rather than their having distinct boundaries, we see a co n ­
tinuous blending o f the characteristics that, on average, distinguish
the different g ro u p s as races.
T he relative geographical isolation o f Africa from Europe and o f both
o f these continents from Asia, com bined with the hazards o f prehistoric
migration over such long distances, produced the three largest and m ost
clearly distinguishable groups: sub-Saharan Africans, Caucasians, and
M ongoloids. There is considerable variation within these broad groups, o f
course, and there are many other derivative or blended groups that could
be called races. T h e number o f races one wishes to distinguish by certain
criteria depends on the criteria used and on how fine-grained the distinc­
tions are. T he precise number o f races is an open-ended and arguable
issue. By certain blood-group criteria, for example, one can even distin­
guish between N o rth Chinese and South Chinese, and between N o rth
Europeans and South Europeans.
M iele: Isn’t saying that the precise num ber o f races is an open-ended
m atter o f dispute equivalent to the cultural constructionist p o sitio n
that “ race” is a subjective (so cio lo gical) rather than an objective ( b io ­
logical) concept?
Jensen: N o , n ot at all, because the criteria for all o f the classifica­
tion s are genetically based. T h e sam e types o f arguments g o on
between “lu m p ers” (who like to lum p the categories together to
reduce their n um ber) and “sp litte rs” (who like to sp lit the categories
into a greater num ber o f sm aller grou p s) am ong taxonom ists, w ho
W H A T IS
RACE?
117
study species and subspecies o f plan ts and animals; am o n g paleoanth ropologists, who stu d y human evolution and classify fossils; and
even am ong dinosaur hunters. T h e im portan t point is th at the aver­
age difference between individuals within a group is less than the
average difference between groups on the relevant physical characteris­
tics, whether at the m olecular level or the gross ph ysical level o f
measurement.
M iele: A nd the secon d definition o f race?
Jensen: In p op u lation genetics, races are defined as breeding pop u­
lation s that differ in the frequencies o f one or m o re genes. T h e
num ber o f genes in which various p op u lation g ro u p s differ serves
as an index o f the genetic distance between them. A n d the world’s
p op u lation can be divid ed up into subp o p ulatio n s b a sed on their
genetic distances. A gain , the num ber o f su b p o p u latio n s will be
rather arbitrary, d ep en d in g on how finely one w ishes to divide the
virtually continuous scale o f existin g genetic d istan ces. Various
experts have distin gu ish ed anywhere between 2 and 7 0 subpopula­
tions, and theoretically one could even increase the u p p er bound.
For exam ple, there are probably different breeding populations
within a city like L o n d o n . They are associated with differen t neigh­
b o rh o o d s and social classes. O f course, the genetic distan ces would
be very sm all com p ared to those between, say, the indigen ous p o p ­
ulation s o f sub-Sah aran Africa, E u ro p e, and A sia. H e re is where
recent attem pts to p rod u ce a politically correct, “ races don’t exist”
term in ology produce confusion. T o be precise, I sh o u ld say north­
ern or northeastern A sian p op u lation s, since the genetic distance
between the p o p u latio n o f India, w hich also is A sian , and that o f
N o rth e rn Europe, is surprisingly sm all, in fact h ardly more than
between, say, those o f England an d o f those o f S o u th ern Europe.
But i f I ju st used the older and no lon ger politically acceptable ter­
m in ology o f the M o n g o lo id race, everyone w ou ld know which
p o p u latio n s I was talk in g about an d which ones I w asn’t, whether
they lived in A sia or anywhere else.
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GENETICS
M iele: Y ou’ve given m e those definitions, but how can you square
them with the policy statem ent o f the American A nth ropological
A ssociation in 1 9 9 8 , which says, “ T h e concept o f race is a social
and cultural construction,” that “ race simply cannot be tested or
proven scientifically,” an d that “ it is clear that hum an populations
are n ot unam biguous, clearly dem arcated, biologically distinct
g ro u p s” so “ the con cep t o f ‘race’ has no validity . . . in the human
species.”
W hy believe A rth ur Jensen, emeritus professor o f educational psy­
chology, and not the Am erican A nthropological A ssociation?
Jensen: Well, I don’t know why the o fficial position o f the American
A nthropological A ssociation is wrong, bu t it is, i f your characteriza­
tion o f their position is accurate. Perhaps they think th at denying the
reality o f race will m ake racial problem s disappear o r help combat
racial prejudice, or they have other well-intentioned m otives that have
more to do with social ideology than with science. Perhaps they
merely wish to be politically correct, which I think is less forgivable
for any group that w ishes to be viewed as a scientific organization.
Further, I don’t think scientific organizations should m ake official
pronouncements on issues that can only be answered in terms o f
empirical research. T h e A A A does n ot speak for all anthropologists,
and probably not even fo r a m ajority o f physical anthropologists, on
this matter.
T h e m ajority o f physical anthropologists, evolutionists, geneti­
cists, and specialists in hum an biology probably take a p osition sim ­
ilar to my own. However, I am in com plete agreem ent with one
im portant point in the A A A statement, and I don’t know anyone who
is up on this subject who would disagree. Races are not biologically clearcut categories or distinct groups. I’ve already said that races are “fuzzy”
groups with clines, or blends, at their blurry boundaries. T h a t’s the
difference between a subspecies or a race as contrasted w ith a species.
A sk any zoologist. T h e fact that I ’m a psychologist rather than an
anthropologist is n ot relevant. T h e consensus o f expert opinion and
the evidence itself su p p o rt my position.
WHAT
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119
M iele: W ell, the m o st extensive, state-of-the-art b o o k on human
genetic variation, The Geography of Human Genes by L . L . CavalliSforza, reaches pretty m uch the same conclusion as the A A A . In the
popu lar volum e C avalli-Sforza co-authored with his son , The Great
Human Diasporas, which sum m arizes his tom e for the layman, he
states that the stability over tim e o f the various physical m arkers we
use to distinguish races is ju st “ not high enough to su p p o rt the cur­
rent definition o f race.”
Jensen: I have studied the tome by Cavalli-Sforza and his co-authors.
H is position on this issue is substantively no different from m y own. In
fact, his work has shaped my own view o f the concept o f race as much
as, or m ore than, anything else I’ve read. T h e book is a m ine o f infor­
m ation about genetic variation between populations. W hile the term
“race” is assiduously avoided, the authors use the term “ population” to
mean the same thing as the second definition o f race I gave you earlier.
T h e visible characteristics— such as skin color, hair texture, and
facial features— used by physical anthropologists in earlier studies o f
racial variation, which serve as the basis o f the first definition o f race
I gave, are usually polygenic (that is, they are determined by the net
effect o f many genes, each causing a slight quantitative variation in
that trait). Cavalli-Sforza’s research, which corresponds to the second
definition o f race, examines genetic polym orphism s such as blood
groups, enzymes, im m unoglobulins, and antigens that have rather
sim ple M endelian patterns o f inheritance. Perhaps the best-known
example o f a genetic polym orphism is the familiar A B O b loo d sys­
tem. T h e different popu lation s around the globe differ in the fre­
quencies o f the A B O genotypes and m any other b lo o d types and
other polym orphism s. F o r example, p eop le o f unm ixed Native
A m erican ancestry generally have type O blood. Since O is recessive
to both A and B, this could be because their ancestors were under
strong selective pressure for som e characteristic either conferred by or
associated with b loo d type O. But it’s m ore likely an example o f
genetic drift, because the N ative Am ericans probably all derive from
a sm all num ber o f ancestors who crossed the Bering lan d bridge.
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Cavalli-Sforza’s research team has gone far beyond the ABO b loo d
g ro u p and calculated the frequencies o f over 100 genes in 4 2 differ­
ent populations fro m all around the world that have lived in their
hom e territory since 1 4 9 2 . T he difference between the frequency o f
each o f the 1 0 0 + genes in one p op u lation and in any other provides
a m easure o f the genetic distance between the two groups. T he team
calculated the genetic distance between each one o f the 42 p op u la­
tion s and the 41 others— a total o f 8 6 1 paired-com parisons. (A s an
analogy, we can use longitude, latitude, and elevation above sea level
[rather than 1 0 0 + gene frequencies] to measure the geographic
[rather than genetic] distance between any two places on the earth. I f
we have longitude, latitude, and elevation [gene frequencies] for 4 2
places [populations], we can then calculate the geographic distance
between each place [population] an d the 41 others, again giving us a
to tal o f 861 paired-com parisons.)
M iele: Okay, you can measure the genetic distance between popu la­
tions, but how does th at produce any “ races” ?
Jensen: T h e races ap p ear when you feed these genetic distance m eas­
ures into a statistical procedure called principal com ponents analysis
(P C A ), which grou p s the individual measures that share some com ­
m on features into a smaller num ber o f clusters, term ed principal
com ponents. Psychometricians regularly use P C A
to determine
which mental tests in a large battery cluster together.
Cavalli-Sforza perform ed a P C A to see which populations w ould
cluster together based on how far apart they were on the 1 0 0 + genetic
m arkers. I perform ed the same kind o f analysis on a different set o f
genetic distance data obtained by geneticists A. K. Roychoudhury and
M asato sh i Nei. O f course, there is genetic variation within the clus­
ters. Nevertheless, P C A does sort the various popu lation s into genet­
ically sim ilar clusters. Both analyses cam e out w ith the same seven
p op u lation clusters based on their degree o f genetic resemblance:
A frican, Caucasoid, N orth east Asian, A rctic Asian, N ativ e American,
Sou th east Asian, an d N ew G uinean/A ustralian. F o r the m ost part, so
WHAT
IS R A C E ?
121
did W illiam W. H ow ells s analysis o f the type o f cranial measure­
m ents used by classical anthropology. I ’ve also used different types o f
statistical analysis. A ll these different m ethods o f analysis and the
different data sets to which they have been applied produce essen­
tially the same picture, which pretty m uch agrees with the racial clas­
sifications o f the old-tim e anthropologists and o f the m an on the
street. It is highly unlikely that a “ mere cultural constru ction’’ would
show such consistency across time, characteristics studied, and
m ethodology. (See T able 4.1 .)
Cavalli-Sforza has graphically sum m arized his results by a linkage
tree diagram in which the genetic distance between any two o f the
seven population clusters is depicted by the length o f the line con­
necting them— the longer the line, the greater the genetic distance.
(See Figure 4.1.)
A s a rough analogy, suppose you could measure a num ber o f lan­
guages in terms o f the similarity o f their basic vocabulary and their
gram m atical structure. You could then calculate the
linguistic dis­
tance” between them. A P C A would then group them into clusters o f
related languages. A n d the result w ould pretty much correspond to
what our ears and h istory both tell us— that Spanish and Portuguese
are closely related to each other. A n d they are related, but not so
closely, to Italian and French, and m ore distantly to English, German,
and even very distantly to Russian and Polish. In other words, youd
get clusters that correspon d to the fam iliar Rom ance language fam­
ily, Germ anic language family, and Slavic language family, and that
while all these fam ilies were related to each other, they showed little
i f any relation to m any other languages o f the world.
A s you can see fro m Figure 4 .1 , on Cavalli-Sforza s analysis o f
genetic polym orphism s, the largest genetic distance lies between the
cluster o f African p opulation s and all o f the others. A m o n g the nonA frican clusters, the largest distance is between the aboriginal N ew
G uin ean /A ustralian cluster and the other clusters. In Howells’s
analysis o f cranial m easurements, however, the A frican cluster and the
N ew G uin ean /A ustralian cluster lie close together. T h is is probably
because natural selection would select for sim ilar head shapes in sim-
122
TABLE 4.1
INTELLIGENCE,
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AND
GENETICS
Comparison of Population Clusters or Races Produced by
Different Investigators and Methodologies
Cavalli-Sforza ’s Tree
Diagram o f Genetic
Frequencies
Howells ’s Tree Diagram Jensen’s PCA o f Genetic
o f Cranial
Frequencies
Measurements
African
African
Negroid
Australia and New
Guinea
Pacific Islands
Australia and New
Guinea
Polynesia
Australia and New
Guinea
Pacific Islands and
Southeast Asia
Southeast Asia
Southeast Asia
Northeast Asia
Japan
Northeast Asia
Arctic North Asia
Eskimo, Ainu, and Guam
Amerind
Amerind
Amerind and Eskimo
European Caucasoid
Non-European
Caucasoid
Caucasoid
Caucasoid
Mongoloid
SOURCES: L. L. Cavalli-Sforza, P. Menozzi, and A. Piazza, The history and
geography o f human genes (Princeton, NJ: Princeton University Press,
1994); W. W. Howells, Getting here: The story o f human evolution
(Washington, DC: Compass Press, 1993); and A. R. Jensen, The g factor:
The science o f mental ability (Westport, CT: Praeger, 1998).
ilar climates. H o t clim ates select for a narrower head shape to m axi­
m ize surface area and thereby m axim um heat radiation to protect the
brain from getting to o hot; cold clim ates select for a m ore spherical
head shape to m inim ize surface area an d thereby m inim ize heat loss
to protect the brain fro m getting to o cold.
M iele: S o that’s your evidence for b iological reality? G iven the asso ­
ciations with those o ld e r ideas o f distin ct, Platonic types that you
WHAT
123
IS R A C E ?
A ustralia a n d N e w G uinea
Pacific Isla n d s
Southeast A s ia
N ortheast A s ia
A rctic A sia
A m erind
E urope
N on -E u ro p ean C aucasian
A frica
A fric a
{I
B
A u s tr a lia a n d N e w G u in e a
A l l C a u c a s ia n s
■C
A m e r in d
Japan
N o r th e a s t A s ia + S o u th e a s t A s ia
-c
E s k i m o (+ G u a m & A in u )
P o ly n e s ia
A p p r o x im a te C r a n io m e tr i c D ista n c e
Figure 4.1 Approximate Major Population Clusters (Races) based on: (A)
Cavalli-Sforza's Analysis o f Genetic Polymorphisms; and (B) Howells'
Analysis of Cranial Measurements.
The horizontal axis in both A and B shows the approximate genetic distance
between the population clusters—the longer the horizontal line, the greater
the genetic distance between the two population clusters. This implies that
they separated earlier in human evolutionary history than clustersthat have
less genetic distance between them. (The vertical dimension is only used to
provide spacebetween the cluster names. It does not represent genetic
distance or anything else.) The analyses of genes (A) and skulls (B) identify
more or less the same clusters or races. One major difference is in the
distance between groups and, therefore, implied time of their separation.
The analysis of genetic polymorphisms (A) shows the greatest distance is be­
tween the African cluster and the Australia-New Guinea cluster (D), while the
analysis of cranial measurements(B) places them close together (d). This is
probably because the cranial measurements were shaped by the similar selec­
tive pressure of hot climates, rather than evidence of a recent common ancestry.
(A) — L . L. Cavalli-Sforza and F. Cavalli-Sforza, The great human diasporas: The
history o f diversity and evolution (Reading, MA: Addison-Wesley,1995); (B) — Howells, W. W.
getting here: The story o f human evolution (Washington, DC: Compass Press, 1993)
so u rc e s:
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RACE,
AND
GENETICS
d ism issed earlier, can “ race” really be used in any legitim ate, scien­
tific way?
Jensen: T h e biologically significant p oin t is that various hum an
g rou p s differ genetically. W hether you call these g rou p s subspecies,
population clusters, breeding p opulation s, varieties, or races is only o f
sem antic, n ot scientific, im portan ce. T h e g ro u p s
traditionally
referred to as the m ajor races differ, on average, in m any genetically
controlled phenotypic physical characteristics. You can find at least
three or four dozen o f them listed in physical anthropology text­
book s.
T h ese average differences in physical traits and genetic polym or­
ph ism s are real, an d they have real-life consequences. T hey allow
forensic specialists to identify the racial background o f individuals
w ith a high degree o f accuracy. T h e n there is the new specialty called
“ racial medicine.” It is based on the recognized fact o f racial differ­
ences in the frequencies o f certain diseases, m edical conditions,
birth defects, and the like. There are now a num ber o f textbooks on
the subject o f racial medicine, and its findings can be critical because
the optim al dosages o f certain d ru gs differ between certain racial
grou p s.
M iele: Okay, but you’re talking m ostly about b lo o d groups and
enzymes here. N o one gets turned dow n for a job, denied housing, or
discrim inated against in any way based on what b loo d type they have.
H o w can you make the leap from these sim ple genetic markers to a
com plex behavior like the g factor, which, as you explained in the pre­
vious chapter, is based on a large num ber o f genes?
Jensen: Given that perhaps as many as 5 0 percent o f the genes in the
hum an genome are involved with the structural an d functional
aspects o f the brain, it would be surprisin g indeed i f populations that
differ in a great m any visible characteristics and in various genetic
polym orphism s d id n ot also differ in som e characteristics associated
w ith the brain, the prim ary organ o f behavior. Carefully controlled
WHAT
IS R A C E ?
125
studies o f infant behavior in the first days an d weeks after b irth have
revealed unmistakable behavioral differences between infants o f
African, Asian, and C aucasian descent. S o we shouldn’t be surprised
i f these races, or population clusters if you prefer, differ in a number
o f behavioral characteristics, including abilities, both ph ysical and
mental as well. It’s as legitim ate and necessary for differential psy­
chology to study psychom etric differences between these g ro u p s as it
is for forensic anthropology to study their skeletal and den tal differ­
ences, geneticists to study their blood g ro u p and im m unological dif­
ferences, or research physicians and pharm acologists to determine
their dosage curves.
Miele: Again, the m ost direct and state-of-the-art evidence we have
now comes from the H u m an Genome Project. M ayb e Robert
Plom in’s research, which you described earlier [in C h ap ter 3], has
identified one or more genes for high IQ . B ut certainly n o one has
found the gene for race ( o r population cluster). Please d o n ’t tell me
that there is a gene for b ein g “ Caucasian,” “ M ongoloid,” “African,
“ Polynesian,” or “Italian,” th at determines your physical traits and
genetic markers, let alone your behavior.
Jensen: O f course, there is no single gene fo r “ race.” A s I ’ve already
explained, races are defined as breeding pop u lation s that d iffe r in the
frequencies o f a num ber o f genes— n o te my use o f th e plural.
N early all o f these genes are present in all biologically n o rm a l mem­
bers o f the human species, and in many oth er species as well. But
many o f the particular alleles that differ between different individu­
als o f the sam e race also have different frequencies in th e different
races. R acial differences are sim ply aggregated individual differences
in the allelic frequencies at a number o f particular genetic loci. Only
rarely are there extreme, all-or-none, racial differences in the fre­
quencies o f any particular gene. One exam ple is the D u ffy blood
group gene, which has a frequency o f a b o u t 4 0 percent in Europeans
and o f near zero in in digen ous West A frican s. But an interm ediate
frequency for D u ffy gene is found am ong A frican A m ericans, which
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IN TE LLIG E N C E ,
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AND G E N E T IC S
is one o f the ways genetics has confirm ed what we know from h is­
to ry about that g r o u p ’s ancestry.
From the tim e th e first Africans arrived in N o r th America in 1 6 1 9
until the present, a real but relatively low number o f interracial m a t­
ings have taken place that have produced a steady infusion o f
C aucasoid genes in to the African Am erican gene p o o l. Virtually all o f
to d a y s African A m ericans have so m e degree o f W h ite ancestry. T h e
average for the entire United S tates is around 2 5 percent, but it run s
fro m as low as 1 0 percent in som e areas o f southern states, to as h igh
as 4 0 percent in so m e northeastern and northw estern states. T h ere
has also been a sm aller percentage o f African genes, estimated at less
than I percent, th a t have entered the W hite A m erican gene p o o l.
Sim ilar analyses o f genetic markers have helped unravel the racial o ri­
gins o f the p eop les o f the Indian subcontinent, L a tm America, an d
oth er areas.
I f the fdum an Genom e P roject progresses ap ace for the next
decade or so, I expect we will fin d direct D N A evidence that som e
behavioral characteristics, including mental abilities, have a genetic
basis and are correlated with race.
F o r more than 3 0 years I have made an extensive study o f the
nature o f B lack-W hite differences in mental abilities and their c o r­
relates with psychom etric and b iological variables. T h e m ost com pre­
hensive and direct explanation fo r the totality o f evidence is what I
have termed the D efau lt H yp o th esis— both individual differences
an d the average Black-W hite difference in the £ fa c to r arise from the
sam e genetic and environmental causes and in a b o u t the same p ro ­
portion s. In other words, there are n o special facto rs that system ati­
cally depress the I Q o f Blacks th at d o not also affe ct I Q in W hites.
T h e environmental and cultural differences betw een Blacks an d
W h ites explain so m e o f the race difference in average IQ , but they
cannot explain all o r even m ost o f it.
M iele: Well, now w e’ve come to w h at’s really been the issue all along,
fro m Jensenism to the Bell Curve W ars. W hat is the evidence for your
WHAT
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127
D efau lt H ypothesis that the mean Black-W hite I Q difference has any
genetic, rather than purely social, econom ic, or cultural, cause?
Jensen: Three m ain lines o f evidence and reasoning argue in favor o f
the D efault H ypoth esis and against any nongenetic, culture-only
hypotheses:
•
First, the culture-only explanations that could be tested have
•
been, and they have been disproved.
Second, what we know about hum an evolution and evolution
in general m akes it likely that i f subspecies (o r races) show
physical differences, they have som e behavioral differences as
•
well.
Finally, there is now a m ass o f research con firm in g
Spearm an’s hypothesis that the m ore a test m easures the g
factor, the greater the Black-W hite difference on that test.
A fter some 3 0 years o f my exam ining this question, I have found
that the Default H ypoth esis more consistently explains all o f the rel­
evant data regarding the Black-W hite differences in a wide variety o f
psychom etric test data and all their real-life correlates— educational,
social, and econom ic— than any entirely nongenetic explanation.
M iele: There are hundreds if n ot thousands o f articles and books
that say exactly the opposite. We can’t examine every nongenetic or
culture-only explanation for the Black-W hite difference in average
I Q , bu t I’d like to present ten o f the best-known, one-by-one, and
have you respond with the evidence you believe disproves them.
Jensen: G o ahead.
M iele: Culture-Only T h e o ry # I — Blacks and W hites differ signifi­
cantly in their average socioeconom ic status (S E S ), and since S E S is a
determ inant o f I Q , it explains the average Black-W hite I Q difference.
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IN TELLIG EN CE,
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GENETICS
Jensen: Racial differences in S E S cannot explain the average IQ dif­
ference. W hen statistical procedures are used to remove the effect o f
the difference in S E S or when Blacks and W hites are sim ply matched
on m easures o f S E S , the Black-W hite IQ difference is reduced, but
only from 15 to 1 2 points. And n ot all o f that three-point reduction
is due to SE S, because S E S differences within each racial group also
have som e genetic component. T herefore matching Blacks and
W h ites on S E S to som e extent also m atches them genetically in terms
o f the g factor.
M iele: Culture-O nly T h eory # 2 — S ch o o l facilities o f Blacks are well
below those o f W hites.
Jensen: Educational inequality can’t explain away the average IQ d if­
ference either. In the last 3 0 years or so many school system s have
been racially integrated and now provide the sam e facilities and
instructional program s for Blacks an d W hites alike, yet the average
differences o f about one standard deviation in I Q and scholastic
achievement remain.
M iele: Culture-O nly T h eory # 3 — I Q only measures knowledge o f
the “ core culture” and therefore the tests are inherently biased against
m inorities.
Jensen: T h e claim that the Black-W hite I Q difference is a result o f
culturally biased tests has been disproved. A detailed explanation,
which requires a w orking knowledge o f psychometrics, is presented
in my 1 9 8 0 book Bias in Mental Testing. B ut you need not take my word
on it. Following publication o f my bo ok , a special com m ittee o f the
N atio n a l Academy o f Sciences and the N ational Research Council
exam ined the question and reached essentially the sam e conclusions,
which I ’ll try to sum m arize as sim ply as I can.
T h e m ost widely used mental tests today have the sam e reliability
for Blacks and W hites, which m eans that i f you give the test to a
group o f people and then test them again at a later date, they get
WHAT
IS R A C E ?
129
about the sam e scores. T h e im portant p oin t is that there is no evi­
dence that the test scores for Blacks are unstable or erratic. W hatever
the tests measure, they m easure it just as reliably for Blacks as for
W hites.
M ental tests also have the sam e predictive validity for Blacks as
they have for W hites. T h is m eans that they predict other im p ortan t
real-life criteria, such as school grades and jo b performance, with the
same accuracy for both groups. I f you’re tryin g to predict how well
som eone will d o in college and they have an I Q o f 125, it m akes no
difference whether they are Black or W hite, o r anything else.
Tests also have the same factor structure in bo th groups. S o i f you
factor analyze the test scores o f either Blacks or W hites on a battery
o f mental tests, you will still find the g factor at the top, follow ed by
the group factors, and then the special factors. T h e g factor is ju st as
real and ju st as im portant fo r Blacks as it is fo r W hites, and indeed,
for any group.
T h e item -to-item correlations are the sam e for both grou ps, and
so is the rank order o f item difficulties. Sim p ly stated, the item s that
are hardest for W hites are also hardest for Blacks, and the item s that
are easiest for W hites are also the ones that are easiest for Blacks. T h is
is im portant because it w ould n ot be true i f som e types o f item s were
specially biased against Blacks— the way vocabulary items, fo r exam­
ple, are biased against recent immigrants w ho are unfam iliar with
English. Blacks and W hites even make the sam e types o f errors and
get fooled into picking the sam e distractor item s in m ultiple-choice
tests.
T h e evidence on each o f these points is so overwhelming th at no
one in the field any longer argues the point.
Miele: Culture-O nly T h eory # 4 — African Am ericans are being tested
in a language other than their own.
Jensen: Insufficient fam iliarity with standard English and the use
“ Black E n glish ” was a pop u lar claim in the 1 9 6 0 s and ’70s. B ut the
Black-W hite I Q differences are as large or larger on a variety o f non­
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INTELLIGENCE,
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verbal tests th at make no use o f alphanumeric sym bols as on verbal
tests. And children who were b o rn deaf and hence have had virtually
n o exposure to spoken language d o not show any deficit on nonver­
bal IQ tests.
M iele: Culture-O nly Theory # 5 — N utrition plays an im portant role
in mental development, as d oes exposure to toxic chemicals and
Blacks and W h ites differ on these measures also.
Jensen: I’ve never claimed that the Black-W hite difference in average
I Q is 10 0 percent genetic, only th at both genetic and environmental
factors are involved, just as w ith individual differences within each
race, and probably to around the sam e degree. N utritional factors do
account for som e part o f the average racial I Q difference. Even when
there is no evidence o f poor nutrition, however, there is still a BlackW hite IQ difference.
In the Black underclass, n utrition does have a measurable effect on
IQ . O n a per-capita basis, prem aturity and low birth weight are m uch
m ore prevalent am ong Blacks th an among W h ites. T he difference
between m oth ers m ilk and baby formulas also makes a significant
difference in the IQ s o f low-birth-weight infants o f either race by the
tim e they reach school age. Unfortunately, at this point in history, a
sm aller percentage o f African Am erican m others breast-feed their
babies. Fortunately, that’s one th in g that could probably be changed
at relatively little cost by m akin g the inform ation better know n in
comm unities, Black or W hite, th at are at highest risk for low -birthweight babies.
M iele: Culture-O nly T heory # 6 — Blacks and W h ites differ m ark ­
edly in their historical experience.
Jensen: To my knowledge, no one has dem onstrated that a g ro u p ’s
p a st history, independent o f its earlier genetic history, affects their
present-day average IQ . Som e racial and ethnic minorities th at h is­
torically have been victimized by discrim ination and persecution,
WHAT
IS R A C E ?
131
such as Jews in Europe, E a st Indians in A frica and in Britain, and
Chinese and Japanese in the U n ited States, actually have higher aver­
age IQ s than the W hite or other m ajority population they live
among.
M iele: Culture-O nly T h eory # 7 — T he totality o f these cultural,
environmental, and nutritional factors interact step by step, from
conception to adolescence, to construct our entire cognitive stru c­
ture.
Jensen: T h is hypothesis could be tested by rearing Black children
from infancy in m iddle-class or upper-m iddle-class W hite fam ilies.
T h a t is what was done in the M innesota T ransracial A doption Study.
T h e researchers com pared infants with two Black parents (HB or
Black in everyday parlance), infants with a W h ite mother and a Black
father (WB, or m ixed race), as well as a control group o f W h ite chil­
dren (WW), all adopted into two-parent W h ite upper-m iddle-class
homes. T h e adoptive parents were mostly college graduates with
managerial and professional jo bs.
All o f the adoptees, Black (BB), mixed race (WB), and W h ite
(WW), were given IQ tests an d scholastic achievement tests at age
seven years and then again at age 17. W hen tested at age seven, aver­
age IQ s for the BB and WB children were several points higher than
the average for Black children reared in the sam e community, in dicat­
ing a beneficial effect o f the m iddle-class, W h ite home environment
on the I Q o f these adoptees. By age 17, however, the average I Q for
the Black adopted children was about 16 p o in ts below the W h ite
average. T h is is not significantly different fro m the national average
I Q for Black youths. So even growing up in a W hite m iddle-class
home did not produce a lastin g reduction in the familiar one stan ­
dard deviation Black-W hite difference in average IQ .
M iele: C ulture-O n ly T h e o r y # 8 — T h e low er average I Q
of
Americans o f African ancestry is the result o f racist A m ericas “ self­
fulfilling prophecy” o f discrim ination against Blacks and even sup-
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INTELLIGENCE,
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GENETICS
posedly “ scientific theories” ab o u t “genetic inferiority” based on the
color o f their skin, not the level o f their £ factor.
Jensen: To som e extent, you can test that hypothesis as well by a m ore
detailed analysis o f the results o f the M in n esota T ransracial
A doption Study. T h e average I Q o f the m ixed race (WB) adoptees,
when they were tested at age seven and again at 17, was ju st about
halfway between the average I Q s o f the WW adoptees and o f the BB
adoptees. Yet there was no m istaking the A frican ancestry o f the
mixed-race children from their appearance. In fact, a WB child w ould
probably be considered “ B lack” in America today, as are well-known
individuals o f mixed racial ancestry such as H alle Berry and T ig er
W oods. It’s h ard to explain the intermediate p osition o f the average
I Q o f the WB adoptees in purely environmental terms, including the
consequences o f societal racism , but it is w hat you would predict
beforehand fro m the D efault H ypothesis. T h e complete results o f
the Transracial A doption S tu d y showed no evidence that, by age 17,
being reared fro m infancy in an upper-m iddle-class W hite fam ily
raised the B lack adoptees’ average I Q or their overall level o f sch olas­
tic perform ance above that o f Black children reared by their b io lo g i­
cal parents.
Miele: C ulture-O nly T h eory # 9 — Experim ental program s o f inten­
sive early cognitive intervention such as the classic “ M iracle in
Milwaukee” successfully increased the IQ s o f Black children.
Jensen: T h e results o f these experimental attem pts to raise the I Q s o f
Black infants at risk for low I Q are quite con sisten t with the results
o f the T ran sracial A d o p tio n
Study. In the highly pub licized
Milwaukee Project, a trained s ta ff gave Black children from p o o r
homes intensive all-day environmental enrichment and training in
mental skills fro m infancy to age six, at which tim e they entered reg­
ular public sch ools. T he sp ecial training raised IQ scores quite
markedly above those o f a con trol group o f sim ilar children w ho did
not receive the training. But the training did n o t significantly raise the
WHAT
IS R A C E ?
133
scholastic achievement an d other kinds o f perform ance that are typ­
ically correlated with IQ . S o the gains in test scores were “ hollow ”
with respect to the g factor. T h e m ost likely explanation is that the
results cam e from “teaching the test,” and n ot really raising the level
o f g.
Miele: Culture-O nly T h e o ry # 1 0 — T h e Milwaukee Project was an
early attem pt at experimental cognitive intervention and naturally had
its lim itations. But the m ore recent A becedarian Project produced
lasting gains in the I Q and school achievement o f at-risk Black chil­
dren. S o b o th the claim in your 1969 H ER article that “ com pensa­
tory education has been tried and apparently it has failed” and your
D efault H ypothesis about intelligence, race, and genetics have now
been disproved.
Jensen: Y ou’re correct that the criticisms o f “ teaching the test” and
“hollow gains” cannot be m ade o f the more recent Abecedarian Project,
which involves intensive and prolonged educational training o f children
at risk for low IQ. T h e project raised the I Q o f the children who
received it about five points, on average, above a control group, who did
not. You’re also correct that this gain still held up when the children
were retested at age 15 and that it was accompanied by a comparable
gain in scholastic performance. And this is all well and good. But it
should also be noted that even the m ost intensive cognitive intervention
program yet devised provided during all o f the children’s preschool
years only reduced the national Black-W hite difference in average IQ by
about one third (that is, 5 out o f 15 I Q points). T his is the best evi­
dence we have o f the extent to which im proving the cognitive environ­
ment o f at-risk groups can increase their IQ . The results o f the
Abecedarian Project in no way disprove the Default H ypothesis o f
genes and environment; they are fully consistent with it.
M iele: T h e n let’s briefly run through the secon d line o f evidence sup­
porting your D efault H ypoth esis that the Black-W hite I Q difference
has a genetic component.
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Jensen: T he secon d line o f evidence looks at the question o f hum an
differences from a broad evolutionary and genetic perspective. R ace
differences in physical traits (like skin color, hair color and form ,
b o d y build, and so on) and in biochem ical and genetic traits (like
b lo o d group frequencies and D N A markers) are the result o f geo ­
graph ic separation, adaptation to different clim ates, as well as any
“ genetic bottlenecks” they p assed through as the earliest hum ans
m igrated out o f A frica, eventually reaching every continent except
Antarctica.
Contrary to w hat some would have you believe, the m ajor races (as
I defined and listed them earlier) differ, on average, in virtually every
anatom ical, physiological, and biochem ical characteristic that also
exhibits differences between individuals within any racial group. It is,
therefore, highly unlikely that there would be no race differences at
all in the 5 0 percent or more o f the total hum an genome that is
involved in brain functions, especially in those p arts o f the brain—
the cortical areas o f the cerebrum, the frontal and tem poral lobes—
th at evolved m ost recently and m o st clearly distinguish Homo sapiens
fro m all other prim ates.
D aniel G. Freedm an’s studies o f Black, W h ite, and Chinese
A m erican infants in the first days and weeks after birth show that
they differ in behavior as well as in their physical appearance. A ll the
neonates were b o rn in the same h osp ital under the same obstetrical
conditions. T h e Black babies were the m ost precocious in m otor
activity and development, the C hinese American babies took the
lon gest to develop in this respect, an d the W hite babies were inter­
m ediate.
M iele: T h a t’s fine fo r simple m o to r behavior. T h e O ut-of-A frica
th eory o f hum an evolution says th at racial differentiation to o k
place 1 0 0 ,0 0 0 or at m ost 2 0 0 ,0 0 0 years ago, lon g before any p o p ­
u latio n developed w hat we w ould call civilization. S o there sim ply
h asn ’t been enough tim e or genetic isolation for the different races
to develop sign ifican t differences in the types o f things that I Q
tests measure.
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Jensen: From an evolutionary standpoint, there is really no question
o f whether races differ in virtually all physical attributes in which we
find individual differences within each race. A n d o f all physical char­
acteristics, none has evolved so rapidly as the human brain, the phys­
ical basis o f m ental abilities. I f 2 0 0 ,0 0 0 years has been enough time
for the m ajor racial groups to differentiate in their physical features,
it was also enough time for som e degree o f racial differentiation in
certain features o f the brain. T h e existence o f racial differences is not
in question, only the direction and m agnitude o f the difference in any
given trait.
Miele: T h a t’s a theoretical argument. D o you have evidence o f race
differences in the anatomy or physiology o f the brain?
Jensen: R acial differences in average brain size are well established, as
is the fact that head size, cranial capacity, an d total brain size corre­
late with g. H e ad size, which provides an estim ate o f brain size in
many older studies, correlates about + 0 .2 0 w ith IQ ; actual brain size,
as m easured by volume in cubic centimeters, has a much higher cor­
relation o f about + 0 .4 0 with IQ .
Miele: You’re sure o f this? G o u ld ’s best-selling Mismeasure of Man and
just about every psychology textbook dism iss this “smart peop le have
big heads” s tu ff as nineteenth-century pseudoscience.
Jensen: W ell, here’s the evidence from the latest research. Y o u decide
which is science and which is pseudoscience. T here are now at least a
dozen independent studies, perform ed in different laboratories
around the world, all published in peer-reviewed scientific journ als, in
which brain size was m easured in living p erson s by m agnetic reso­
nance im aging (M R I). In alm ost every study brain size— to ta l vol­
ume in cubic centimeters— was significantly correlated with IQ . The
average correlation from my analysis o f the ten different studies then
available is about + 0 .4 0 . In one study I fo u n d that head size was
specifically correlated with the g factor extracted from a battery o f 17
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diverse tests. Furtherm ore, the degree to which each o f the 17 tests
correlated with h ead size within each racial grou p predicted the size
o f the average W hite-Black differences on these 1 7 tests, with a co r­
relation o f 0 .5 1 , because head size provides an estimate o f g, and
Black-W hite differences are prim arily on the g factor.
Evidence from a number o f independent studies o f racial d iffer­
ences in cranial capacity and in autopsied brain volume and brain
weight show approxim ately 100 g ram s difference between the average
autopsied brain weights o f Blacks and W hites m atched for sex, age,
an d overall body size. Also, E ast A sian s are fo u n d to have som ew hat
larger brains than European C aucasians, and their average IQ is a b o u t
six points higher.
M iele: But even i f I Q is directly dependent on brain size and W h ites,
on average, have higher IQ s and bigger brains than Blacks, couldn ’t
this be because, on average, W h ites enjoy a m ore enriching environ­
m ent? There are classic studies th at show that, even among lab orato­
ry rats, an enriched environment directly influences the development
o f the brain.
Jensen: Research on children in the T h ird W orld who during certain
critical periods in their early developm ent have been severely deprived
nutritionally— fo r example, by a fam ine— grow u p to have som ew hat
sm aller bodies an d smaller heads an d brains than children who d id
n ot suffer this deprivation. T h e vast m ajority o f the Black population
in the U nited States, however, h as the same level o f nutrition as
W h ites. T he estim ates I have seen o f the largest possible effects o f
nutritional factors on the average I Q o f Am erican Blacks som e 2 5
years ago was one o r two IQ p o in ts, and in the p o o rest parts o f the
D e e p South, p ossib ly as much as fo u r IQ points.
Yet the correlation between h ead size— and by inference, brain
size— and I Q exists independently o f the kinds o f nutritional or
other environmental differences associated with differences between
fam ilies in socioeconom ic status or racial origin. In a study o f
1 4 ,0 0 0 full siblings, every pair o f sibs reared together, I found that
W H A T IS R A C E ?
137
the sibs differed from each other in b o th head size and I Q , and their
difference in head size correlated positively with their difference in
IQ — the sib with the higher IQ , on average, having the larger head.
Because it compared siblings within the sam e family, the correlation
could n ot be the result o f any differences between fam ilies in their
S E S or hom e environment.
T h e correlation between head size and I Q o f siblings was found in
both the W hite and the Black samples, each having about 7 ,0 0 0 indi­
viduals. T here was a significant difference between the Black group
and the W hite group in average head size and in average IQ . But when
Blacks an d W hites were matched for I Q , we found that they didn’t
differ in head size at all. M atching on I Q controls for all the brain
variables related to I Q , including brain size, but m atching for head
size controls only som e sm all part o f all the variables that relate to IQ .
M iele: Y o u ’ve covered your first two lines o f evidence that argue for
som e p a rt o f the Black-W hite difference in average I Q having a
genetic com ponent— the failure o f culture-only theories to hold up
when they have been tested, and the general evolutionary reasoning
which says that if subspecies or races show physical differences, there
is som e behavioral difference as well. N o doubt your third line o f evi­
dence relates to the g factor.
Jensen: Yes, it involves what I have called “ Spearm an’s hypothesis.” In
his b o o k The Abilities of Man, Spearm an m ade a casual observation that
the size o f the average W hite-Black difference on ten diverse tests was
directly related to his subjective im pression o f how m uch each test
reflected the g factor— the more g, the greater the Black-W hite dif­
ference. I turned Sp earm an s offhand conjecture into an empirically
testable hypothesis by calculating the average Black-W hite difference
for a num ber o f diverse mental tests, obtaining the g loadin g for each
test (th at is, how m uch each test m easures g), and ranking the average
W -B differences and the g loadings. I f the rank order o f the BlackW hite differences and the g loadings are pretty m uch in the same
order, Spearm an’s hypothesis is confirm ed.
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I’ve now tested Spearm ans hypothesis on 2 5 large independent
sam ples and it has been confirm ed on every one. It has held up for
m any different test batteries, and at every age level from three-yearo ld s to m iddle-aged adults. N o r d id m atching Blacks and W hites for
S E S diminish the effect. It even show s up in reaction-tim e tests that
have different g loadings but require no cultural knowledge and can
be perform ed in less than one or tw o seconds by elementary school
children. Based on all these studies, the overall probability that
Spearm an s hypothesis is false is less than one in a billion!
M iele: I ’m sure th at’s interesting to psychom etricians, but how does
it show that genes are responsible fo r the Black-W hite average differ­
ence in IQ?
Jensen: Because g is significantly related to many other variables that
fall outside the realm o f psychom etrics and factor analysis. Som e o f
these variables are genetic, some are anatom ical and physiological,
and som e are occupational and social. A n d many have im portant reallife consequences.
M iele: Let’s take the genetic variables first. W hat have you found out
a b o u t g, other than the fact that the twin and kinship studies show
that mental ability is to some extent heritable within each race?
Jensen: I have discovered som ething m uch more specific. T h e more a
test measures the g factor, the higher is its heritability. In various stud­
ies that com pared a diverse set o f tests, their respective g loadings and
heritabilities correlated between 0 .6 0 and 0.80.
N ex t is the phenomenon o f inbreeding depression, which we dis­
cussed earlier— the weakening or dim inution o f a m etric trait in the
offsprin g o f parents who are closely related. [See Chapter 3.]
Inbreeding depression o f IQ has been found in at least 14 independ­
ent studies around the world. Inbred children born to first-cousin
m atings average about seven to ten I Q points lower than children born
to comparable parents who are not genetically related to each other.
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T h e connection to the g factor that you’ve been waiting for is that
the more ¿-loaded the test is (that is, the more it measures g), the more
inbreeding works to decrease scores on that test. For the offspring o f
cousin matings, the correlation between g loadings and the effect o f
inbreeding depression on those tests is about 0.80. T h e opposite o f
inbreeding depression— the effect known as heterosis, or hybrid vigor—
is due to outbreeding between people whose genetic distance from one
another is greater than the average genetic distance in the general pop­
ulation (in other words, m ating between people o f quite different racial
ancestry). A study o f the effects o f outbreeding on m ental abilities
found the converse o f the inbreeding depression studies: the larger a
test’s g loading, the greater the enhancing effect o f heterosis on outbred
children’s scores on that test. I know o f no environmental, cultural, or
attitudmal factor that can account for these findings, but they are all
not only explainable but even predictable from a genetic hypothesis.
T h e g factor specifically reflects a large genetic component.
M iele: T h e n let’s go on to the physiological correlates o f the g factor.
W hat are they?
Jensen: There are two kinds o f physiological measurements that show
a relationship to g. T h e first are brain-wave measurements— the ampli­
tude and the complexity o f the average evoked potential (A E P ), which
is the electrochemical response o f the brain to a b rief external stimu­
lus, such as an audible click or a flash o f light. T he am plitude reflects
the brain’s activity level in response to the stimulus. T h e person being
tested has a recording electrode attached to his or her scalp and does­
n’t have to do anything more than sit in a chair and relax while 2 0 0
clicks (o r flashes) are presented in series, every two seconds. T h e ampli­
tude and the complexity o f the A EPs to the 2 0 0 clicks (o r flashes) are
averaged just as you w ould average 2 0 0 paper-and-pencil test scores.
O n ce again, the im p ortan t point is that the size o f the correlation
between the A EP measurements and a variety o f m ental tests is highly
predicted by the tests’ g loading. H igh-^ subjects have m ore complex
wave-forms and a lower amplitude. I f you use statistical methods to
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remove the effect o f the g factor fro m the test scores, their correla­
tion with the brain’s electrical activity disappears. S o the brain-wave
measurements are specifically related to the g factor.
A nother measure o f brain physiology that has been found to be
related specifically to g is the brains glucose m etabolic rate (G M R )
during mental activity, such as taking an I Q test. T h e G M R is m eas­
ured by means o f a P E T -scan (Positron Em ission T om ograph y) pro­
cedure. Just as h igh er-IQ subjects show less am plitude o f the AEP,
they also show a lower G M R in response to the same test items. T h at
is, the brain response o f high-^ subjects is more efficient because they
require less “ fuel” [that is, glucose] to d o the same am o u n t o f “brain
w ork” as a person who is lower in g.
M iele: Y ou’ve m entioned the Spearm an Effect, but you haven’t men­
tioned the Flynn E ffect. There is also evidence that average IQ s are
increasing all around the world and m o st o f the increase is because
people at the lower end o f the socioeconom ic spectrum have been
doing better. Doesn’t th at show that I Q test performance is a function
o f the m odern technological cultural com plex and A frican Americans
and T h ird World peoples are simply the last ones to be allowed to
enter? S o does the Flynn Effect trum p the Spearman Effect?
Jensen: T h e raw scores on several widely used standardized IQ tests
have been gradually risin g by about the equivalent o f three I Q points
per decade for the p a st five decades. T h e causes o f this effect are still
a mystery. M y hunch is th at the gain in test scores over tim e is a com ­
bined result o f four trends that have taken place in the industrialized
nations over the p ast few decades: ( I ) a greater use o f standardized
tests and a resultant increased fam iliarity with test taking, (2 )
improvements in education and m ore years o f sch oolin g for more
people, ( 3 ) improved nutrition and health care, and ( 4 ) advances in
obstetrical practices and in inoculations o f m ost children against the
form erly common ch ild h ood diseases.
However, a PC A perform ed by J. P. Rushton, sim ilar to those used
for the racial classifications I described, has shown th at the increase
WHAT
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141
in I Q scores over tim e is on the tests’ specific knowledge content and
skills and not on the g factor. H e foun d that g factor form s a cluster
with biological factors such as inbreeding depression and heritability,
bu t the Flynn-Effect increase in scores does not. In brief, neither a
theoretical nor an empirical connection has been established between
the Flynn E ffect and the average Black-W hite I Q difference.
M iele: You’ve presented a great deal o f evidence to su p p ort w hat
you’ve term ed the D efau lt H y p o th esis that both environmental an d
genetic factors are involved in causin g the average Black-W hite d if­
ference in I Q and especially in g. S o m e o f that evidence was also
presented in The Bell Curve. In respon se to the controversy su r­
rou n din g that bo ok , the A m erican Psychological A ssociatio n
ap p oin ted a special com m ission to lo o k into the question. It was
h eaded by cognitive psych ologist U lric N eisser and included
T h o m a s Bouchard, who con ducted som e o f the twin studies you
referred to earlier; N ath an Brody, who has written the m ost w idely
u sed textbook on intelligence; D ian e H alpern, an expert on sex d if­
ferences in cognitive ability; R o b e rt Sternberg, editor o f
The
Encyclopedia of Intelligence• to which you have contributed; and several
other experts.
H ere are their conclusions regarding race, intelligence, and genetics:
T h e mean differential between the mean intelligence test scores
o f Blacks and W hites (about one standard deviation, although
it may be diminishing) does n ot result from any obvious biases
in test construction and administration, nor does it simply
reflect differences in socioeconom ic status. Explanations based
on factors o f caste and culture m ay be appropriate, but so far
have little direct empirical support. There is certainly no such support
fo r a genetic interpretation. At present, no one knows what causes
this difference. [T h e emphasis is mine.— F.M.]
S o was the com m ittee clueless as to all you have told me in this
chapter? I f not, how could a num ber o f scholars, including n oted
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psychom etricians and hereditarians, p ut their names and the APA
im prim atur on the conclusion I just quoted?
Jensen: I can’t answer that, but I do think they should have spelled
out in m ore detail why they think it so unlikely that genetic factors
are involved, and how they would interpret, in purely environmental
terms, the kinds o f evidence I have presented. I f they had done that,
we could get a grip on their reasoning. I think they were much too
cavalier in dism issing genetic factors with so little consideration.
A s I read the APA statem ent, however, I didn’t feel it was contra­
dicting my position, but rather was merely sidestepping it. It seems
more evasive o f my p o sitio n than contradictory. T h e com m ittee did
acknowledge the factual status o f what I have termed the Spearm an
Effect, the reality o f g, the inadequacy o f test bias and socioeconomic
status as causal explanations, and many oth er conclusions that don’t
differ at all from my own position. R em em ber, it was the report o f a
com m ittee, so I suspect the joint statem ent went about as far as they
all were willing to agree or would com m it themselves to regarding
this socially and politically sensitive issue. Considering that the
report was com m issioned by the APA, I was surprised it went as far
as it did. View ed in that light, I am not especially displeased by it.
M iele: T h e n let me read you one more quotation:
W ith the encouragem ent o f Christianity, people had dissem i­
nated the doctrine o f the equality o f all men. Gypsies,
H o tten to ts, Botocudos, and Teutons are all said to be equal.
U nfortunately N ature . . . teaches us otherwise— there are
higher and lower races. T o equate that racial hotchpotch, the
C handalas, with the Aryans, those hum an aristocrats, is to
com m it a crime against mankind, for to attain higher develop­
ment, m ankind needs leaders as well as leading nations. O f all
the races on this earth, it is the Teutonic . . . which is called
upon to play that leading role.
WHAT
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RACE?
143
T h a t’s not fro m the APA, but fro m the Völkischer Beobachter; the N a z i
party newspaper. S o m e people w ould say that everything you’ve to ld
m e in this chapter is nothing bu t the old, disproven, and dangerous
idea o f an im m utable, eternal hierarchy o f races, sim ply recycled with
contem porary references and repackaged in m ore palatable term inol­
ogy. Any comment?
Jensen: I haven’t said a word ab o u t any “hierarchy o f races,” “higher
and lower races,” “ aristocrats,” or a “ master race.” T h o se concepts are
nonsense in term s o f what we know about racial variation. Racial d if­
ferences are not at all unidim ensional or unidirectional, and it’s m ean­
ingless to speak o f a difference without specifying a particular
dim ension, characteristic, or trait. W h at I’ve investigated is the distri­
bu tion o f individual differences in one particular dim ension, namely
the g factor, both within groups an d between g rou p s, and their p ro b ­
able genetic and environmental causes. How is that scientifically d if­
ferent from lo o k in g at the distribution o f height, blood pressure,
visual acuity, or any other m etric characteristic in those or other
groups, and inquiring about environmental and genetic factors influ­
encing those variables?
Your quotation from the N a z i p arty newspaper reflects a typolog­
ical, essentialist view o f individuals and races as distinct Platonic
types— an ou tm od ed view that has long been know n to be wrong.
T h ere is no single gene that causes “ black” skin, a mean IQ o f 85,
dark hair, or hypertension; nor is there any other single gene that
causes “ white” skin , a mean I Q o f 100, blond hair, and myopia. Each
o f these particular phenotypes is separately the result o f a number o f
genes, and their effects become m anifest during the course o f devel­
opm ent, with environmental factors certainly playing a role. T h e sta­
tistical correlations among these variables at this poin t in time doesn’t
determine their possible distribution and statistical correlations at
som e future p o in t in time. I f we had, say, ten generations o f racial
interbreeding, all these statistical associations w ould diminish to the
p o in t that we’d sim ply be talking about individual differences.
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M oreover, I never said anything about preserving the genetic
“ purity” o f any race or group. Rather, I explained in som e detail the
negative effects o f inbreeding and the positive effects o f outbreeding
both on physical m easurements and on IQ . A nd I also explained why
they provide som e o f the best evidence for the influence o f genetic
factors on those traits within each group and for genes playing a part
in the difference between groups.
A s to the im plied charge o f racism or neo-N azism , I absolutely
disavow any association whatsoever between my views and th ose you
quoted from that N a z i party newspaper. I have always rejected that
kind o f thinking, ever since I was a child, and so did my parents and
all my other relatives. S o I hope we can turn to the im portan t ques­
tion o f why the scientific issue o f average race differences in mental
ability has been so badly m isrepresented n ot only by the popular
m edia but even by som e in the scientific community. We need to dis­
cuss how society can best use scientific inform ation in form ulating
public policy.
M iele: T h en we shall in the next chapter.
Further Reading
T h e literature on the concept o f race is so volum inous that only the m o st direcdy rele­
vant b ook s and articles can be cited here. F or a com plete and technically detailed discus­
sion o f the evidence and argum ents Jensen presents in this chapter, see: Jensen, A. R.
(1 9 9 8 ). The ¿factor: The science of mental ability. W estport, C T : Praeger (especially chapter I I ,
Population differences in g, and chapter 12, Population differences in g: C au sa l hypothe­
ses).
I have sum m arized the history o f the nature-nurture debate and its relation to the raceI Q question in: M iele, F. (2 0 0 1 ). T h e shadow o f Caliban: an introduction to the tem­
pestuous history o f anthropology. Skeptic, 9 ( I ) , 2 2 - 3 5 . T h e 1998 Statem ent on Race by
the Am erican A nthropological A ssociation was reported in a number o f newspapers, my
own source being: The San Francisco Chronicle (1 9 9 8 ). (2 3 February), A I .T h e argum ent that
race is a social construction rather than a biological reality is made m o st strongly by:
Smedley, A. R . (1 9 9 9 ). Race in North America: Origin and evolution of a worldview. (2 n d E d.)
Boulder, C O : Westview. T h e diam etrically opposite view that race is an extremely impor­
tant concept in explaining not only intelligence and brain size but over 6 0 other variables
WHAT
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145
including neonate behavior, speed o f maturation an d longevity, personality and tempera­
ment, family stability and crime, sexual behavior an d fertility is sum m arized in: Rushton,
J. P. (2 0 0 0 ). Race, evolution, and behavior: A life history perspective (2nd special abridged edition).
Port H uron, M I: Charles D arw in Research Institu te; and is presented in depth in:
Rushton, J. P. ( 2 0 0 0 ). Race, evolution, and behavior: A life history perspective (3 r d unabridged edi­
tion). Port H uron , M I: Charles D arw in Research Institute. The d efin itio n o f races as
“ fuzzy sets” appears in: Sarich, V M . (1 9 9 5 ). In defense of the bell curve: T h e reality o f
race and the im portance o f h um an diversity. Skeptic, 3 (3 ), 84—93. A lth o u gh it was pub ­
lished more than 2 5 years ago, the following is w orth consulting for its breadth and evenhandedness in covering this con tentious issue: Loehlin, J. C., Lindzey, G ., and Spuhler, J.
N . (1 9 7 5 ). Race differences in intelligence. San Francisco: W. H . Freeman.
T h e tom e on genetic polym orph ism s in human populations is: Cavalli-Sforza, L. L.,
M enozzi, P., and Piazza, A. ( 1 9 9 4 ) . The geography of human genes. Princeton: Princeton
University Press. It is sum m arized for the layman, alo n g with a criticism o f Jensen and
Jensenism, in: Cavalli-Sforza, L . L „ and Cavalli-Sforza, F. (1 9 9 6 ). The great human diasporas:
The history of diversity and evolution. R eadin g, MA: A d d iso n Wesley.
T h e issue o f test bias was explicated in all its psychometric detail in: Jensen, A. R .
(1 9 8 0 ). Bias in mental testing. N e w Y ork: Free Press. H i s findings were largely confirmed in:
W igdor, A. K., and Garner, W. R . (E d s .) (1 9 8 2 ). N ational Academy of Science report: Ability test­
ing: uses, consequences, and controversies. W ashington, D C : N atio n al Academy Press.
T h e study o f race differences in infant behavior is: Freedman, D . C ., and Freedman,
N . C. (1 9 6 9 ). Behavioral differences between Chinese-American and European-Am erican
newborns. Nature, 2 2 4 , 1 2 2 7 .
T h e report issued by the A m erican Psychological A ssociation on the race-IQ question
in response to The Bell Curve is: N eisser, U „ et al. (1 9 9 6 ). Intelligence: Knowns and
unknowns. American Psychologist, 5 1 , 7 7 —101.
For more inform ation on these subjects, see the bibliography o f Je n se n s publications
in Appendix A.
5
FROM J E N S E N I S M
TO THE B E L L C U R V E WARS
Science, Pseudoscience, and Politics
I
n this chapter our conversation m oves from the science o f the race-IQ
issue to the larger political issues that lurk behind it and make it so
inflamm atory. I cite the contradiction between Jefferson’s words in the
D eclaration o f Independence that “ all men are created equal” and his
derogatory statem ents about the m ental ability o f Blacks in his Notes on
Virginia, as well as sim ilar remarks m ade by American presidents from the
G reat Em ancipator, A braham Lincoln, to Richard N ixon , who assigned his
s ta ff to report to him on Jensen’s fam ous HER article. W hen I offer these
as evidence that anti-Black racism has been central to Am erican political
history, Jensen responds that such statem ents have no scientific value, n or
should they prevent science from look in g into the subject. In fact, he says,
the only intelligent way to resolve the age-old conflicting theories o f
hum an nature that are an integral p art o f politics, religion, and philosophy
is through behavioral science.
Jensen’s defense o f academic freedom and scientific inquiry leads to a
discussion about the controversial Pioneer Fund, the sm all foundation that
has supported hereditarian research, including Jensen’s. I ask Jensen to
respon d to the charges by two o f his and the Pioneer F u n d ’s severest crit­
ics. Psychologist Jerry Hirsch, who, ironically, had studied genetics with
U C Berkeley geneticist Everett D em pster, as did Jensen, and like Jensen, is
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a m em ber o f the Behavior Genetics A ssociation , described Jensen as a
“ charlatan” and his work as “ science w ithout scholarship.” Barry Mehler,
who w orked with H irsch, charged that from its very beginning the Pioneer
Fund n ot only supported “ race science” bu t helped fuel race conflict in the
U nited States.
M ehler also claim ed th at Jensen was “ recruited” for the Pioneer Fund
by the late W illiam Shockley. Shockley h ad shared the 1 9 5 6 N o b el Prize
in Physics with John Bardeen and W illiam Brattain, his coworkers at Bell
Labs, for the developm ent o f the transistor. T h en in 1 9 6 5 U.S. News &■
World Report published an interview with Sh ockley entitled “ Is the Q uality
o f the U .S . Population D eclining?” in which he drew attention not only
to the Black-W hite difference in average I Q but also to the higher
birthrate am on g A m ericans with lower I Q , even m ore prevalent am ong
Blacks than am ong W h ites. Shockley also suggested p ossible corrective
policies including elite-contributor sp erm banks (he and three other
N o b el laureates would later contribute to one such bank set up in
C alifornia) and what he called a “thinking exercise.” H e p ro p o sed that, as
an alternative to the existing welfare system , society consider a Voluntary
Sterilization Bonus Plan un der which lo w -IQ non-taxpayers who agreed
to be sterilized would have the sum o f $ 1 ,0 0 0 per I Q p o in t below 100
paid into a tru st account on their behalf. (Sh ockley em phasized both the
heuristic nature o f the plan and its restriction to non-taxpayers.) C oupled
with his contentious style in debates and lectures, these p rop o sals made
Shockley an increasingly controversial figure on college cam puses in the
late 1 9 6 0 s and early ’70s.
Jensen emphatically dism isses the statem ents by H irsch and M ehler as
ad hom inem vituperation and contends that those who have valid, scien­
tific criticism o f his work sh ould subm it their critiques to the appropriate
peer-reviewed journals. W h en they have done so, Jensen has replied.
Jensen com m ends the relatively sm all Pioneer Fund for having the
intellectual courage to su p p o rt psychom etric research on the nature o f
intelligence, and behavior genetic studies o f individual and group differ­
ences in ability (especially the race-IQ q uestion ), which government and
large private foundations have been afraid to touch. Jensen has received
grants from other foundations and governm ent agencies during his career
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and has reviewed articles for leading journals, and he says the Pioneer
F u n d s review process is just as thorough. Indeed, he says, Pioneer follows
a “ no strings attached” policy, which many other foundations or govern­
m ent agencies do not.
W e also discuss the question o f why, i f the evidence in its favor is as
strong as Jensen says it is, Jensenism is often treated as “ fringe science,” like
creationism or hom eopathic medicine. Jensen totally rejects that character­
ization, countering th at Jensenism is regarded as m ainstream science by
experts in the relevant disciplines. A s evidence, he cites Snyderman and
R oth m an’s survey o f the members o f the Behavior Genetics A ssociation
(B G A ) and o f the Am erican Psychological A ssociation ’s (APA) Division
5— T ests and M easurem ent (each A PA division bein g com posed o f spe­
cialists in that area), and a statement by 5 0 behavioral scientists printed in
the Wall Street Journal (which has not, on the whole, given favorable coverage
to Jensenism ) under the headline “ M ainstream Science on Intelligence.” I f
that is so, I ask, why have organizations such as B G A , APA Division 5, and
the Educational T estin g Service ( E T S ) remained silent?
W h ile critical o f m o st mass m ed ia coverage o f the issue, Jensen has the
highest praise for the presentations by some o f the “ quick studies” who
have interviewed him — Joseph A lsop , Lee E d son (The New York Times
Magazine), M orton H u n t (Playboy), D an Seligm an (Fortune), and M ike
W allace (for two ep isodes o f C B S ’s 6 0 Minutes). But, Jensen says, m edia
pieces should not an d cannot decide what is scientifically correct. W h a t is
im portan t is that readers and viewers understand how behavioral scientists
approach such questions.
M iele: T he D eclaration o f Independence says “ all men are created
equal” and "endow ed by their C reator with certain unalienable R ights.”
T h o u g h the Declaration carries no binding legal weight, it has been an
inspiration to the abolitionist, suffragist, and civil rights movements,
an d even the U N E S C O Declaration o f Rights. T h e U.S. Constitution,
on the other hand, which is the supreme law o f the land, contains no
such words and severely restricted those it originally defined as citi­
zens— women were n ot guartanteed the vote, slavery was accepted, the
N ative Americans were pretty m uch written off, and so on.
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S o from the very first, hasn’t there been a tension, indeed a con­
tradiction, between what we preach about hum an rights an d what we
practice based on our beliefs about human nature?
Jensen: Yes, o f course, there have been tensions, contradictions,
ambivalence, and outright disagreem ents about the nature o f human
nature throughout history, not just Am erican history. T h is is why it
is so im portant for science to get into the picture, to try to find out
what is and isn’t true about apparently conflicting notions o f human
nature. T h is is the task o f the behavioral and biological sciences. T he
job is uphill, not only because o f the strictly scientific problem s, but
also because o f the entrenched beliefs and prejudices from the past.
I f our faith in science is too weak to overcome these obstacles, we
m ight as well give up, because there is no other means fo r obtaining
reliable knowledge.
M iele: Well, contrast those oft-quoted words o f Jefferson, a slave
owner, in the D eclaration with these much less often q u o ted words
from his Notes on Virginia:
Com paring them [Blacks] by their faculties o f memory, reason,
and imagination, it appears to me that in m em ory they are
equal to the whites; in reason much inferior, as I think one
could scarcely be found capable o f tracing and comprehending
the investigations o f Euclid; and that in imagination they are
dull, tasteless, and anom alous.
A braham Lincoln, the G reat Em ancipator, in his 1 8 5 8 debates
with Stephen D ouglas, declared:
there is a physical difference between the white and Black races
which I believe will forever forbid the two races living together
on term s o f social and political equality. A n d inasmuch as they
cannot so live, while they do remain together there m ust be the
position o f superior and inferior, and I as much as any other
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man am in favor o f having the superior p o sitio n assigned to the
white race.
T heodore Roosevelt, hero o f the Progressive Era in A m erican pol­
itics, said, “ T h e N egro, fo r instance, has been kept down as m uch by
his lack o f intellectual developm ent as anything else,” and “ in the
m ass, the N e g r o [is] altogether inferior to whites.”
According to John Ehrlichm an, Richard N ix o n told him th at he
believed that America’s B lacks could only marginally benefit from
federal program s because they were genetically inferior to W h ite s. All
the federal m oney and p ro g ram s we could devise could n o t change
that fact. T h o u g h he believed that Blacks co u ld never achieve parity
in intelligence, economic success, or social qualities, we sh o u ld still
do what we could for them , within reasonable limits, because it was
“ right” to d o so.
D on’t quotes like that prove that anti-Black racism is as A m erican
as apple pie?
Jensen: Your examples an d quotations are political history, an d are
interesting fro m that stan dpoin t. But they have no scientific value and
so hold no fascination fo r m e at all. There are many scientific sub­
jects that incur this kind o f liability. Darw in feared the consequences
o f publishing his theory o f evolution by n atural selection, b u t in his
day this liability came fro m religion rather th an politics.
M y own interest is n ot a t all political, b u t i f anyone th in ks there
are political overtones in any o f my work, I h ope they take the trou­
ble to understand me correctly. I myself d o n ’t feel inclined o r prop­
erly qualified to think th rou gh what others m ay consider the “ poli­
tics” o f my work.
Miele: T h e m ost recent incarnation o f Jensenism has been The Bell
Curve wars. T h a t b o ok
w as co-authored by the late R ichard
H errnstein and Charles M urray, who has served as a dom estic pol­
icy advisor fo r the R eagan adm inistration an d for R epublican and
conservative politicians. D o n ’t the critics w ho claim Jensenism and
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The Bell Curve underm ine public su p p o rt for progressive or egalitarian
program s have a point?
Jensen: It’s debatable whether these academic issues actually u n d er­
m ine or even influence public actions. I wish there were some way o f
knowing. However, it should be a realistic concern for such critics i f
“ progressive” an d “ egalitarian” social program s, to use your w ords,
are actually contradicted by so lid evidence. G o o d intentions m u st be
backed up by evidence that the prescribed m eans fo r achieving th em
actually work.
T h e marked individual differences and average race and sex d iffer­
ences in abilities are real and im portant in relation to education,
employment, and other social an d economic variables. It is presently
n ot withm our power to materially reduce these differences by purely
psychological or educational means, or any other m eans yet known. I f
so-called progressive programs depend on the egalitarian notion th at
such differences are only a superficial effect o f unequal social privilege
or lack o f opportunity and can be changed easily by psychological and
educational interventions or m easures such as A ffirm ative Action, they
are in conflict with the evidence an d need to be seriously reconsidered.
M iele: Well, th ose who argue fo r the political im plications, i f n o t
inherent nature, o f your work an d similar research by behavioral sc i­
entists always p o in t out that it has been generously supported by the
Pioneer Fund. W h a t is the Pioneer Fund?
Jensen: It’s a sm all foundation as compared with a great many others,
such as the Ford, Rockefeller, Carnegie, Guggenheim , and M ello n
Foundations, for example. Its area o f interest is m ainly research in d if­
ferential psychology, or the study o f individual an d various group d if­
ferences in behavioral traits relevant to education, employment, an d
other socially significant aspects o f the human condition, such as p o p ­
ulation growth, im m igration, welfare dependency, delinquency, an d
crime. I believe it has supported research projects in all these areas. It
accepts and reviews grant p roposals from anyone w ho submits them ,
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and it also invites established scholars to subm it research proposals in
any o f these areas. T h e research typically concerns the b asic science
relevant to the study o f human variation, such as psychometrics,
behavioral genetics, and cognitive abilities. For a small foundation, its
record o f accom plishm ents is remarkable. It has a high battin g aver­
age for sponsoring research that has had high impact in the field.
Miele: D o you have any second thoughts, misgivings, or qualms
about accepting Pioneer Fu n d support, for this or any other work
you’ve been involved in?
Jensen: N o t in the least. I have had many grants from various federal
agencies and private foundations, and I can say that the Pioneer
Fun d’s grants have never h ad any strings attached, as have gran ts made
by som e funding sources. T h e Pioneer F u n d ’s support o f research on
the genetics o f intelligence and particularly on the subject o f racial
differences in educationally and socially im portant hum an traits is
the only basis I have been able to find for the criticisms I have seen
m ade o f the Pioneer Fu n d. It has been willing to sup port research on
socially sensitive issues at a time when few, i f any, other agencies were
willing to fund such research. T h e name “ Pioneer” is indeed very apt.
M iele: Are you fam iliar with all the work the Pioneer F u n d has sup­
ported and do you have any concerns or criticism s o f any o f it?
Jensen: N o, I haven’t m ade a study o f all the research sponsored by
Pioneer. T h a t would virtually preclude doing my own work. But I am
very familiar with studies they have sponsored that are related to my own
research, naturally. I judge each piece o f research on its own merits, and
o f course one can often find points in the work o f others and in one’s
own work that can be criticized in some respect. Analysis, search, skep­
ticism, and criticism are all part o f the scientific enterprise. N o research
is exempt from such scrutiny, regardless o f who funded it. A s a member
o f the editorial boards o f five psychological journals during the past 35
years, I have critically reviewed hundreds o f articles subm itted to these
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journals. I have seen no reason to believe that the standard met by
Pioneer-funded research differs significantly from that sponsored by
other private foundations or federal granting agencies.
M iele: One o f the Pioneer Fund’s principal critics, Barry Mehler, has
charged that it has funded academ ics whose w ork on “genetically
based race differences” could be u se d in support o f eugenics and to
o p p o se integration an d im m igration and to su p p ort other right-wing
causes. In a backhanded acknowledgment that its im pact far exceeded
its size or the size o f its grants, he credits the Pioneer Fund with
“ bein g at the cutting edge o f alm ost every race co n flict in the U n ited
States since its fo u n d in g in 1937.”
A ny comment?
Jensen: T he notion th at the Pioneer Fu n d has h ad anything at all to
do w ith race conflict in the U n ited States or anywhere else is utterly
ridiculous as well as totally false. T h e rhetoric o f the passage you
qu o ted sounds as i f it was crafted to be as defam atory as possible. I
used to see a lot o f such rhetoric directed at me personally, in p am ­
ph lets and placards produced by dem onstrators fro m various radical
studen t groups in the 1970s, m ost o f them now defunct. T h at q u o ­
tation is o f the very sam e ilk.
M iele: In the same article, M ehler says that your H ER article claim ed
that because Black children had an average IQ o f 8 5 , no amount o f
com pensatory education could im prove their perform ance. And that
since you were “ recruited ” for the Pioneer Fund by W illiam Shockley,
the F u n d has provided you with m ore than a m illion dollars in grants
over the past three decades.
Jensen: T h at is so exaggerated and fu ll o f falsehoods and inaccuracies
that it would be o tio se to give a detailed critique. I f anyone has legit­
im ate scientific criticism s o f my research, they sh o u ld subm it them to
the sam e respectable peer-reviewed journals in which my research
appeared. Many sch olars have done this, either on their own initiative
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or by an editor’s invitation, and, as is the custom, I have been allowed
to reply in the sam e journal. T h a t is the way o f science. T h e intem­
perate and slanderous propaganda pieces m asquerading as criticism
that you have m entioned are som ething else again, and are worthy o f
contem pt from the scientific community.
M iele: Mehler began criticizing you and the Pioneer Fu n d as part o f
Jerry H irsch’s program studying “A cadem ic Racism .” Like you, H irsch
is a psychologist who then became interested in behavior genetics. In
fact, he told me at a meeting o f the Behavior Genetics A ssociation that
both o f you had studied the subject with Everett D em pster o f the
University o f C alifornia Berkeley genetics department.
H avin g started fro m the same research question at the same point
in time, how and why do you think you and H irsch arrived at such
op p o site and adversarial positions that he felt com pelled to write
papers entitled “ T o U nfrock the Charlatans” and “Jensenism: T h e
Bankruptcy o f ‘Scien ce’ W ithout Scholarship.”
Jensen: I have no way o f fathom ing H irsch’s attitudes and actions,
and I doubt that it w ould be worthwhile for me to attem pt to do so.
M iele: Well, how abo u t his use o f the term “ charlatan” ?
Jensen: It’s just m ore o f the purely ad hominem vituperation I just
described.
M iele: W hile Stephen Jay Gould d id not indulge in any such personal
attacks, he did strongly attack all three tenets o f Jensenism — the exis­
tence o f the g factor, the heritability o f differences in g, and especially
that p art o f the cause o f the Black-W hite IQ difference is genetic.
The Mismeasure of Man won m ore awards and so ld a lo t more copies
than The g Factor. Even i f you com bine the sales o f all the books writ­
ten fo r a general audience that take a more or less “Jensenist” point
o f view— such as your own Straight Talk About Mental Tests (which is out
o f prin t) Dan Seligm an’s A Question of Intelligence, and H an s Eysenck’s
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posthum ously published Intelligence: A New Look— they’ve so ld nowhere
near as many copies. I ’d like your evaluation o f the im pact and scien­
tific m erit o f The Mismeasure of Man.
Jensen: I wrote a lengthy review o f the book, titled “ D ebunking
Scientific Fossils and Straw Persons.” G o u ld ’s Mismeasure of Man is
engaging and entertaining, but virtually worthless as scholarship, and
it has alm ost nothing to d o with the current picture in the study o f
hum an mental abilities. G o u ld was an excellent writer, and I was sorry
that he applied his talents to producing such a m isleading book.
The Mismeasure of Man d id receive the accolades in the pop u lar media
and am ong the literati you mentioned, b u t mine was not the only crit­
ical review. T h e b o ok was also panned in the specialist journals by
reviewers with a technical background in psychometrics and behav­
ioral genetics. G ould claim ed that the g factor, which he called the
“ rotten core” o f Jensenism , is a chimera, a fantasy, just an artifact o f
psychom etrics and factor analysis. T h is argument is thoroughly re­
futed by the evidence o f the biological reality o f g, which I present in
detail in The g Factor an d which I sum m arized in our earlier discus­
sions. [See Chapters 2, 3, and 4.]
O utside the sphere o f psychometrics and differential psychology, my
attitude toward G ould was largely positive. I admired and supported his
battle against creationist efforts to demote Darwinian thinking in high
school biology courses and textbooks. W hen it comes to human varia­
tion in psychological or behavioral traits, however, G o u ld himself
seemed to be a creationist rather than an evolutionist. I regard differen­
tial psychology as a branch o f human biology, and I would have hoped
that that Gould did also. T oo bad he never wrote an autobiography,
which might have explained the origins o f his antipathy toward psycho­
metrics, the g factor, and their relevance to advancing the scientific study
o f human differences. T h a t would have been m ost interesting.
M iele: But in m ost social science texts Jensenism is likened to creationism or flat-earthism . Are you telling me that there’s some
Inquisition going on to stam p out the Jensenist heresy?
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Jensen: To liken the behavior-genetic view o f hum an variability and g
theory to creationism or anything like that is o f course ridiculous. I
can’t think o f any biologically oriented psychologist who is actually
inform ed on the issues connecting biology to psychometrics, indi­
vidual differences, and genetics who would believe that.
Som e people m ay fear there is a kind o f in quisition going on. For
new Ph.D.s, the inquisition against the so-called hereditarian position
is perceived as consisting o f narrowing the range o f their em ploy­
m ent opportunities— particularly in college teaching. M id-career
psychologists are concerned abo u t prospects fo r prom otion and ris­
ing in the profession via being elected to offices in their professional
organization, being appointed to influential comm ittees, getting
research grants, an d winning awards. There’s no d o u b t this happens.
M iele: Can you give me specifics, naming nam es, o f any serious
scholars having a problem publishing com petent articles in the best
peer-reviewed jo u rn als today?
Jensen: I won’t nam e names, because that w ould require my getting
perm ission from the named p erson s and w ould also violate the co n ­
fidential nature o f my role as a jo u rn al referee. I presently serve on
the editorial b o ard s o f four psychological jo u rn als and am fre­
quently a consulting editor for at least h alf a dozen more. I actually
d on ’t know o f a case within the p ast two or three years where a
technically co m p eten t article th at is co n sid ered controversial
because it dealt w ith racial differences in m ental abilities has been
denied publication in a reputable journal on spurious groun ds.
However, there is no doubt th at a double stan d ard o f review still
exists; articles d ealin g with the race-IQ -genetics nexus when the
results have n ot com e out in the politically co rrect direction have to
p a ss a much m ore critical review process than i f the results were in
the opposite direction.
However, I will give examples fro m my own publishing experiences
in the 1970s and 1 9 8 0 s. One quite key article subm itted to an APA
journal, for example, showed a racial difference on certain tests that
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was practically im possible to explain in term s o f culture bias or any
other environmental or m otivational factors anyone could think of.
T h e study was technically impeccable. But the review process took
about three times as lon g as usual for that journal. T h e editor even­
tually accepted the article as is, and apologized for the lon g delay,
which resulted from the fact that the article had to be sent to seven
reviewers rather than the usual three in order to get three real reviews
o f the paper itself. T h e other four supposed reviews were m erely ad
hom inem diatribes; the editor said it w ould be too em barrassing to
the journal for me to be allowed to see them.
M y first article on S p earm an s hypothesis was also subm itted to
the APA’s house journal, which claims to take no more than ten weeks
to make an editorial decision on unsolicited m anuscripts. T h e y took
eleven m onths with my m anuscript, and responded only after I had
written to them asking fo r a decision. T h o u g h two o f the referees
wrote highly favorable com m ents on the article, the third one did a
hatchet jo b on it, m aking utterly trivial criticisms, and the editor
rejected the article w ithout option to resubm it. I figured it m u st have
taken the editor about ten m onths to find som eone willing to provide
the trivial and spurious reasons for rejection. I have saved this whole
correspondence as o f possible historical interest, because it is such
prim a facie evidence o f bias by APA’s house journal. T h e article was
then subm itted to Behavioral and Brain Sciences (1 9 8 5 ), was critically
reviewed by no fewer than I I referees, and was accepted and pu b­
lished along with com m entaries by 3 0 experts in the relevant fields. I
received over 1,500 reprint requests for that article, and it has been
highly cited. I could easily go on and on with other exam ples from
my own experience, but they are much the same. I am glad to say that
I have seen considerably less o f this so rt o f thing within the last few
years.
Miele: T h e anti-Jensenist position is presented in w orkshops for
teachers by the N ation al Educational A ssociation (N E A ) and sim i­
lar groups. Are they afraid o f losing governm ent funds i f the public
starts to believe that education is not om nipotent?
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Never afraid to challenge sacred cows, here Jensen in New Delhi, India, feeds some. (Fall 1 9 8 0 )
Jensen: I know too little a b o u t the N E A ’s leadership a n d their
m otivation to make any in fo rm e d com m ent. But I do k n o w that
after the pub lication o f m y b o o k Bias in Mental Testing, th e N E A
spon sored lectures and w o rk sh o p s that denounced my b o o k and
prom oted the notion that I Q and sch olastic aptitude tests are cul­
turally b iased against B lacks and certain oth er m inorities in the
sch ool p op u lation . T h is h as been the p o litica lly correct p o sition ,
and perhaps the N E A is m erely following th a t line on all th e issues
in its purview.
M iele: Well, d o you think the race-IQ q u estion should b e studied
and discussed in high school or introductory college courses at all or
should it be left for upper-division college an d graduate classes?
Jensen: It shouldn’t be explicitly made a to p ic for silence in high
school or lower-division courses in college, b u t students sh o u ld be
to ld that a p roper understanding o f the issues depends u p o n a good
deal o f prior background in som e o f the technical aspects o f psy­
chology. You can only d iscu ss these m atters before an uninform ed
group the lim ited way you co u ld discuss, say, quantum m echanics in
front o f a group with no background in physics and math. F o r stu-
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Dressed in a kurta, Jensen stands infront of the Taj Mahal Hotel in Bombay, India, while on a
33-lecture tour of Indian universities. (December 1 9 8 0 )
dents without sufficien t background, time is better spent providing
the background knowledge long before ever gettin g into its ap p lica­
tion to the ra ce-IQ issue. But there’s also no n eed to tell beginning
psychology studen ts things that are not true.
Regardless o f the subject, I d on ’t like to tell studen ts bare facts or
conclusions w ithout their having knowledge o f the kinds o f evidence
and reasoning required either to su p p o rt or to disconfirm a p a rtic u ­
lar hypothesis. Scien tific psychology is best taught in terms o f em p ir­
ical hypothesis testing. Students sh ould know clearly the hypothesis,
the methods for testin g it, and the results o f the test. W ithout th o se
m inim um requirem ents, they are le ft with no real knowledge o f the
subject, only p rejudices on whichever side o f the issue.
M iele: D o you th in k students co u ld handle the su b ject or would even
w ant to listen?
Jensen: Absolutely, provided they are given the background inform a­
tion necessary to understand it. C ollege freshmen an d sophom ores are
very eager to learn more about things discussed by the media. O n e
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year while teaching at Berkeley I had heard som e things from a couple
o f students who were taking an introductory psychology course that
led me to suspect their class was being ill inform ed by the instructor
on such things as the nature o f intelligence, and the evidence for its
heritability. Based on their input, I complained to the departm ent and
it resulted in my being invited to give the lectures for the unit specifi­
cally dealing with the genetics o f IQ . W h at im pressed me m o st was
the level o f interest in this subject and the open-m indedness and high
quality o f the questions that were asked. Interestingly, students were
m ost interested in the subject o f assortative m ating (the tendency o f
like to m ate with like), its degree in human matings, and its genetic
and psychological consequences for the population at large.
In my last year o f teaching at Berkeley, I h ad a freshman class in
an introductory course. I was again struck by the studen ts’ open­
m indedness and spontaneity in asking intelligent questions ab o u t vir­
tually every aspect o f the I Q controversy. It seemed very different
from the doctrinaire and opinionated attitudes o f the students I
encountered 2 0 or 2 5 years earlier. I believe that students today, pro­
vided they haven’t been in college too long or haven’t taken many
courses in the social sciences, are more curious and fair-m inded than
were students o f an earlier generation.
M iele: Earlier we discussed the special APA comm ittee repo rt on The
Bell Curve. I believe there were earlier APA resolutions that circulated
around APA about your HER article and the whole issue o f
Jensenism. W h at’s your opin ion o f the APA, specifically D ivisio n 5,
Testing and M easurement?
Jensen: M y HER article was harshly denounced by one D iv isio n o f
the APA called the Society for the Psychological Study o f Social
Issues (S P S S I) in the APA’s house journal, American Psychologist, which
also published my reply to this quite inept critique. M y com plaint
with APA’s Division 5, which represents psychological m easurement
and quantitative psychology, is that they never, or hardly ever, defend
this branch o f psychology against those who criticize it. A s far as I’m
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aware, for exam ple, only two members o f D ivision 5, Lloyd
H um phreys and
myself, ever published a critique o f G o u ld s
Mistneasure of Man, which attacked n o t only Jensenism but psychologi­
cal testing and m easurement in general. And ou r critiques were n ot
published in any jo u rn al controlled by Division 5. T o o many m eas­
urem ent psychologists have, in m y opinion, been negligent in defend­
ing their own field against attacks by patently incom petent critics
fro m outside the field and ideologues who o p p o se the whole idea o f
studying human variation in behavioral traits. M o s t academicians, o f
course, speak up on controversial issues only after they are no longer
controversial. I f it weren’t so disheartening, it w ou ld be am using to
see so many o f th em run for cover when threatened by ideological
criticism .
M iele: Well, p erh aps the Behavior Genetics A ssociation has been
m ore willing to take up the race-IQ issue?
Jensen: N o t only h as it not don e so, it has conspicuously avoided
d o in g so. Don’t a sk me why. I d o n ’t really know; you’ll have to ask
them . One speculation that is com m on, and p robably true to a large
extent, is that gettin g into the race-IQ issue in term s o f genetics
w ould threaten on e’s receiving research grants fro m federal agencies,
and many behavioral geneticists’ research is su p p o rted by federal
grants. It would be a true loss i f sup p ort for this research, which is
generally excellent an d essential fo r advancing the science, were cut
off. T h e appropriations to the federal granting agencies are controlled
by Congress, which is, o f course, a political body. S o when it com es
to m uch o f the scien tific research done in the U n ite d States, politics
rules. And some research topics are more at the m ercy o f Political
Correctness than others. There are also more subtle personal reasons
fo r distancing o n e se lf from view ing the race question in a genetic
context. Anyone w ho does so risks getting called a racist and is often
m isunderstood an d even shunned by friends or colleagues. It puts one
in a difficult p o sitio n socially and professionally, which not everyone
can tolerate. I m y se lf don’t like it, but I som etim es wonder why I
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seem to tolerate it. I believe one has to have relatively little need to be
liked. I su p p ose it’s a kin d o f eccentricity to be willing to risk strong
disapproval.
Miele: T h e Snyderman and Rothm an p oll o f APA D ivision 5 and
B G A m em bers, which we discussed earlier, found that the m ajority
agreed w ith the three tenets o f Jensenism. [See Chapter I.] W hy
haven’t they come out with resolutions to that effect?
Jensen: Personally, I don’t think that a scientific organization as such
should pronounce resolutions and the like dealing with questions o f
a substantive and empirical nature. In science these questions are not
answered by a show o f hands.
However, self-selected individuals or research teams sh ould be free
to publish their analyses and conclusions abo u t a book such as The Bell
Curve. T h is has been happening to som e extent, although m o st o f the
critiques o f The Bell Curve are pretty pathetic from a scientific stand­
point. You may know th at som e 5 0 experts in the branches o f the
behavioral sciences m o st relevant to the subject matter o f The Bell
Curve p u b lish ed a statem en t in the
Wall Street Journal called
“ M ainstream Science on Intelligence.” It contained a list o f 2 5 points
that they regard as scientifically well established and m o st generally
accepted involving the basic issues involved in the controversy sur­
rounding The Bell Curve. Y our readers m ight well appreciate having this
list, as an appendix to this book. I think it would be w orth includ­
ing, as I was among those who signed that statement. [See A ppendix
B.]
M iele: T h e organization with the greatest stake in the reality and
im portance o f g is the E ducational T esting Service. H as E T S made
any official statement concerning your work, either on g or in behav­
ior genetics, or on Jensenism and The Bell Curve wars?
Jensen: N o n e at all, as far as I know. However, E T S did spon so r a
two-day Spearm an Sym p osium at the University o f Plymouth,
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England, and I was invited to give the opening Spearm an Lecture. I
talked about Sp earm an ’s hypothesis that the Black-W hite difference
on various psychom etric tests is directly related to how well each test
m easures the g factor. [See C hapter 4.]
T h e race question, however, is n o t a research to p ic at E T S . T h e ir
research m ission lies strictly w ithin the realm o f ensuring the relia­
bility, validity, an d fairness o f their tests. They have no reason to do
research on the genetics o f m ental ability or to make pronounce­
m ents about it.
E T S concentrates its efforts on developing the best tests possible
fo r predicting scholastic perform ance. T hey have long employed
som e o f the w orld’s top experts in psychom etrics who have done
im portant research on detecting an d eliminating cultural bias from
tests. T heir tests stan d up well fo r the claims that E T S makes for
them.
M iele : Let’s turn to book publishing. The Bell Curve, no matter what
the m ass m edia m ay have said a b o u t it, was a best-seller and a com ­
m ercial success. H o w do you think the success and controversy o f The
Bell Curve affected the publication, sales, or m edia coverage o f your
b o o k , The g Factor? Please be specific. D id the fact that Chris Brand, a
controversial figure for a number o f reasons, came out with a b o o k
w ith the same title somewhat earlier, sour people on the “g factor” in
general?
Jen sen : I think The Bell Curve had a salutary effect in bringing the sci­
entific issues before a large segm ent o f the Am erican public, regard­
less o f one’s agreem ent or disagreem ent with the public policy ideas
in its final chapter. The Bell Curve gave general currency to Spearm an’s
con cept o f the g factor. But there were many scientifically uninform ed
people in the book-publishing w orld who were easily led to believe
th at The Bell Curve was wholly u n so u n d scientifically. S o when I d is­
cussed the prospects o f my b o ok The g Factor with the psychology edi­
to rs o f several large publishing firm s, including one that had p u b ­
lished The Bell Curve as well as tw o o f my earlier b o o k s (Bias in Mental
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Testing an d Straight Talk About Mental Tests), I discovered an unusual wari­
ness ab o u t anything having to do with the g factor. O n e editor told
me his firm regarded The Bell Curve as pseudoscience and said they
would have no interest in a book that was consonant with the psy­
chom etric and substantive aspects o f The Bell Curve.
T h e psychology ed ito r at another large publishing house, who read
m ost o f the m anuscript o f my book, w as quite enthusiastic about it.
T h e sam e firm first publish ed and then withdrew a b o o k also titled
The g Factor by C hristopher Brand, a well-known psychologist at
Edinburgh University, which was already in print and ab o u t to go on
the m arket. A dem onstration by d issid en t students and a bad press
provoked by Brand’s p ress conference cau sed the publisher to de-publish B ran d ’s book immediately. T h e publishers said they found
Brands b o o k “repugnant” (their exact word), although they were
never w illing to state specifically w hat they considered repugnant
about it. A bout two w eeks later, the m an uscript o f my b o o k with the
same title, The g Factor, w as returned to m e via Federal E xpress with a
brief letter from the ed ito r saying they decided this wasn’t the right
kind o f b o o k for them to publish. I im m ediately sent the m anuscript
o f f to another publisher, who kept it fo r about five m on th s and then
returned it, without a letter, totally w ithout any com m ent at all.
Finally, m y book was accepted and publish ed, after rejection by eight
other publishers. T h is w ould be o f no interest if it were a crummy or
incom petent piece o f work, but the experts in this field who were
asked by the publishers to review the m anuscript expressed highly
favorable opinions o f it and urged publication.
T h e reviews o f The g Factor in the profession al journals so far have
been highly favorable. I think it was the tw o chapters (o u t o f 14) that
discussed racial differences in g that caused so many publishers to
decide again st acceptance. M y experience, however, was n o t unique. I
know o f tw o publishers that were w illing to relinquish a huge advance
on royalties for solicited and contracted bo ok s when they found that
they touch ed on racial differences, even in the m ost m in or way. It has
been m y experience th at i f a book d oesn ’t denounce or completely
dism iss the idea that genetics may have anything to do with racial dif­
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ferences in any behavioral trait, especially intelligence, m ost publish­
ers will not touch it.
M iele: Let’s discuss the gatekeepers o f the Zeitgeist— the m ass media.
Y our HER article got a rather g o o d treatm ent by The New York Times
Magazine. The Bell Curve received g o o d coverage in Newsweek and Forbes.
Skeptic, for which I write, devoted p a rt o f two issues to The Bell Curve
controversy, much o f the coverage unfavorable, but n o t all o f it.
S o is there really a special hostility on the part o f the mass media
to Jensenism, or is it just getting m ixed treatment, depending on who
is doing the story and where it’s being published, ju st like any other
issue? D o you have any evidence o f any special hostility to you or your
views by the m ajor news magazines, newspapers, or radio and T V ?
Jensen: W hat you are saying is generally correct. It’s usually a mixture
o f favorable and unfavorable treatm ent. T h e power o f the m ass
m edia, however, is m ore evident in what they choose to notice or to
ignore and leave unmentionable. A lso, as you suggest, a lot depends
on who gets the assignm ent to cover a particular topic. But you have
picked out the very best examples th at immediately com e to mind.
The New York Times Magazine, for exam ple, asked one o f the top pop u­
lar science writers (L e e E dson ) to d o the story on my 1 9 6 9 Harvard
Educational Review article, and I know he took pains to get the story
right. T h e science p art o f the Newsweek story about The Bell Curve was
very well done, because the s ta ff writer who was assigned to work on
this article also to o k the trouble to understand the issues and explain
them sim ply but correctly. However, the typical level o f objectivity
and accuracy in dealing with the I Q controversy that one generally
finds in the m ass m edia is quite p o o r and largely at variance with
expert opinion on these topics. I f anyone wants full docum entation
on this point, I again refer them to Snyderm an and R othm an’s book
The IQ Controversy: The Media and Public Policy.
M iele: T hen are you ready to declare victory for Jensenism , at least as
regards the scientific journals?
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Jensen: I think so. N o t in the sense th at everyone or even a m ajority
believe everything I have written on these subjects, b u t in the sense
that they are now open for discussion on that basis.
M iele: Given your generally low evaluation o f the m edia, let me turn
the tables on you. S it in my seat for a moment. You’ve been assigned
to cover a new controversy in science or history and you know little
about the specifics. H o w would you g o about it? H ow w ould you pre­
pare? O r determine who is “ qualified” and who is “ unbiased” ?
Jensen: I’d like to see these really to u gh questions tried on a journal­
ist or a professor o f journalism ! N o t having worked on that side o f
the equation, I haven’t given these m atters as much thought as they
deserve. But I have been interviewed by many journalists, in the print,
radio, and T V media, and what I have noticed is that som e do a much
better jo b than others, an d this usually has to do with their prepara­
tion and understanding o f the subject under discussion. Theirs is
really an exceedingly d ifficult task, because they’re n o t in a position
to becom e highly expert in every particular subject that they are
assigned to write or interview about. I really admire the people who,
in my own experience, have done this exceptionally well. T he names
that immediately com e to mind are Joseph A lsop, Lee Edson,
M o rto n H unt, D an Seligm an, and M ik e Wallace, w ho interviewed
me on tw o occasions for the 60 Minutes T V program s. I was rather
am azed at how well prepared and knowledgeable they came for their
interviews with me. T h e y ’re all obviously brilliant fellows.
I don’t know how these men prepared, but I can tell you how I
think you m ight go abo u t it. Talk to the editors o f the specialist jour­
nals for the topic in question. Tell th em the topic yo u ’re working on
and ask for two things: a m inim um b asic reading list on the specific
topic, and the names o f the five or six m ost qualified persons you
could talk with about the particular to p ic. I f you have the time, look
these people up in, say, Psychological Abstracts, the Science Citation Index,
Who’s Who, and the author index o f textbooks on the subject o f inter­
est, to get som e idea o f their backgroun d and contributions to the
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field. T h e number o f a textbook’s page references to the cited works
o f a person is a strong clue as to the leadin g contributors to a given
field. T alk with them about the topic o f your assignment. T h e rest is
up to your intelligence, understanding, an d judgment.
M iele: H ow would you determine the scientific consensus, or does
that really mean anything?
Jensen: T h e idea o f a consensus is not very meaningful o r im portant
in science, especially at the frontiers o f knowledge. A t first, a con­
sensus is nearly always o p p o sed to any innovation. T h e technical com­
petence o f the work is a better guide. Behind the frontiers o f a devel­
opin g science, o f course, a consensus o f generally accepted opinion
am ong workers in a given field may be quite meaningful. For exam­
ple, there is now such a consensus am o n g experts in psychometrics
and behavioral genetics regarding the practical validity o f I Q tests,
the existence o f a g factor, and its substan tial heritability, to mention
only a few points.
M iele: W h at does it mean to, as they say, “ have an agenda” ? Is some­
one with an agenda necessarily wrong as to the science involved?
D oesn ’t everyone have som e agenda?
Jensen: H aving an agenda per se, o f course, can have nothing to do
with the truth in a scientific sense. A scien tist’s personal beliefs are o f
no im portance when it comes to evaluating the scientific truth o f
that scientist’s theories. N ew ton, for exam ple, believed m any things,
such as alchemy, that today we would con sider false and even bizarre,
but that in no way invalidates his scientific discoveries, which have
held up now for over three hundred years. W hen there is evidence,
however, that a person has a ph ilosophical, religious, or political
agenda that, instead o f scientific considerations, determ ines the kinds
o f evidence to be accepted or rejected, it becomes especially impor­
tant to evaluate the p erson s claims in lig h t o f all the relevant empir­
ical evidence, the m eth odology used in arriving at conclusions, and
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the logic and internal consistency o f the arguments based thereon. I
assum e everyone has som e kind o f agenda.
M iele: Okay. T h en what’s Arthur Jen sen s agenda?
Jensen: M y own agenda is to bring psychology m ore fully into the
larger dom ain o f biology, and to ap p ly the m ethods o f differential
psychology, psychom etrics, and behavioral genetics to bear on som e
o f the questions concerning the causes o f individual and group d if­
ferences that have arisen especially in the field o f education. M y aim
in this is to produce good science, as best I can, n o t to change the
w orld or push any social or political program.
M iele: M o st im portan t o f all, what sh ould make m y BS-D etector h it
red alert?
Jensen: Your “ red alert” should go o f f whenever you see wishful
thinking replace the reality principle or encounter any form o f d o g ­
m atism , which is an anathema to science. On this, there’s a m em o­
rable passage in Bertrand Russell’s Mysticism and Logic that I especially
like and that I recom m end to scien tists and science writers alike:
T h e man o f science, whatever his hopes may be, m u st lay them
aside while he studies nature; an d the philosopher, i f he is to
achieve truth, m ust do the sam e. Ethical considerations can only
legitim ately appear as determ ining our feelings towards the
truth, and our manner o f orderin g our lives in view o f the
truth, but not as themselves dictatin g what the tru th is to be.
Further Reading
T h e statem ents by N ixo n can be found in: Ehrlichmann, J. ( 1 9 8 2 ) . Witness to power. N e w
York: S im o n and Schuster. Pp. 223. For the historical record o f presidential statem en ts
on race, see: O ’Reilly, K. (1 9 9 5 ). Nixon’s piano: Presidents and racial politics from Washington to
Clinton. N e w York: Free Press.
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Jerry H irsch ’s article criticizing Jensen is: Htrsch, J. ( 1 9 8 1).T o defrock the charlatans.
Race Relations Abstracts, 6.2, 1—6 6 . F o r Barry M ehler’s criticism s o f the Pion eer Fund, see:
Mehler, B. ( 1 9 8 9 —1 990). Fou n d atio n for fascism : T h e new eugenics movement in the
U nited States. Patterns of Prejudice, 2 3 (W inter), 17—2 6 . O ther critiques that appeared as
part o f
The Bell Curve W ars” include: Lane, C. ( 1 9 9 4 ) . T h e tainted sources o f “the bell
curve.” New York Review of Books ( I December), 15; L an e, C. (1 9 9 5 ). I Q , race and hered­
ity. Commentary, 1 0 0 (August), 1 5 - 2 5 ; Miller, A. ( 1 9 9 4 ) . Professors o f hate. Rolling Stone
(2 0 O ctober), 1 0 6 —114; and Sedgw ick, J. ( 1 9 9 4 ). T h e mentality bunker. Gentlemen’s
Quarterly (N ovem b er), 2 2 8 —2 5 1.
For biograph ies o f the Pioneer Fund’s principal grantees and sum m aries o f their
research, written from a pro-Pioneer perspective, see Lynn, R . (2 0 0 1 ). The science of human
diversity: A history of the Pioneer Fund. N e w York: U niversity Press o f Am erica. T h e book also
contains a lengthy preface by the late H arry F. Weyher, long-tim e president o f the Pioneer
Fund, in which he responded to m any o f the charges m ade against the F u n d in the arti­
cles cited above. H e also published defenses o f the Pioneer Fund in: Weyher, H . F.
(1 9 9 8 a ). T h e pioneer fund, the behavioral sciences, an d the media’s false stories. Intelligence,
2 6 (4), 3 1 9 —3 3 6 ; and in: Weyher, H . F. (1 9 9 8 b ). C ontributions to the history o f psy­
chology, C X II: Intelligence, behavior genetics, and the Pioneer Fund. Psychological Reports,
8 2, 13 4 7 - 1 3 7 4 .
T h e book s recom m ended by Jensen for the general reader are: Jensen, A. R . (1 9 8 1).
Straight talk about mental tests. N ew Y ork: Free Press; Seligm an , D. (1 9 9 2 ). A question of intelli­
gence: The I Q debate in America. Secaucus, N J: Birch L ane; and Eysenck, H . J. (1 9 9 8 ).
Intelligence: A new look. N ew Brunswick, N J: Transaction. T h e opposing, anti-Jensenist point
o f view is well presented in: G o u ld , S. J. (1 9 9 6 ). The mismeasure of man. (Revised and
expanded edition ). N ew York: N o r to n ; and Graves, J. L . (2 0 0 1 ). The emperor’s new clothes:
Biological theories of race at the millennium. N ew Brunswick, N J: Rutgers U niversity Press.
T h e evidence o f media bias cited by Jensen is b ased on: Snyderman, M „ and Rothman,
S. (1 9 8 7 ). Survey o f expert opin ion on intelligence an d aptitude tests. American Psychologist,
4 2 , 1 3 7 - 1 4 4 ; an d on their 1 9 8 8 follow-up book , Snyderman, M ., an d Rothman, S.
(1 9 8 8 ). The I Q controversy: The media and public policy. N e w Brunswick, N J: Transaction.
T h e statem ent signed by 5 0 behavioral scientists, reproduced in A ppen dix B, origi­
nally appeared as Gottfredson, L . (1 9 9 4 ), M ainstream science on intelligence, Wall Street
Journal (D ecem ber 13), A 1 8. It was later republish ed as G ottfredson, L. (1 9 9 7 ),
M ainstream science on intelligence: A n editorial w ith 5 2 signatories, history, and bibli­
ography, Intelligence, 2 4 ( I ) , 13—2 3 .
For more inform ation on these subjects, see the bibliography o f Jensen’s publications
in Appendix A.
6
S C I E N C E AND POLICY
Whats to Be Done?
T
he final chapter deals with an area that Jensen has rarely entered— pol­
icy. W hen Jensenism becam e an issue, he avoided drawing policy
im plications. O nly recently and tentatively has he done so. After all, the
severest critics o f Jensenism and other “ race research” have always argued
that it is a smoke screen to hide a reactionary political agenda. We debate
whether there is som e general rule, such as “science an d politics don’t mix,”
and whether questions about hum an beings should be treated differently
fro m other scientific questions. Jensen argues that successful policy m ust
be based on reality, not wishful thinking, and th at’s where science gets
involved.
I question whether Jensenism didn ’t have a p o licy angle from the open­
ing line o f his fam ou s Harvard Educational Review article: “ C om pensatory
education has been tried and apparently it has failed.” H e explains that
when the findings o f the U.S. C om m ission on Civil R ights showed that
com pensatory education program s did not raise the I Q and scholastic
achievement o f the culturally disadvantaged, it contradicted what he and
educators thoroughly believed at that time. H e w ondered why. T h e n an­
other government-financed study, the fam ous 1 9 6 6 Colem an R eport,
com pared our nation’s schools in terms o f per-pupil expenditures,
pu pil/teach er ratios, and teacher qualifications. T aken all together, they
failed to explain m ore than 10 percent o f the variation in scholastic per-
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formance. Ju st spending m ore m oney per pupil, hiring new teachers, or
providing them with better training would n ot eliminate the differences.
T h ey were the result o f som ething in the p u p ils’ family backgroun d fac­
tors, som ething the schools couldn't influence. Jensen began to think that
he and others weren’t asking the right questions and were lo o k in g in the
wrong places for the answers.
We then turn to what that m eans for two o f the m ajor policies in this
area— E qual O pportun ity and Affirm ative A ction. Jensen says th at he has
always believed in equal opportun ity for every individual, regardless o f sex,
race, religion, national ongin, or any other classification, but that this doesn’t
ensure that everyone will achieve equal results. F o r Jensen, opportunities,
like everything else, only make sense in term s o f individual differences. T he
aim o f public education should n ot be to produce equality (w hich it can’t),
but to provide a variety o f opportunities to allow children to benefit in
whatever way works best for them.
W hen Affirm ative A ction was introduced it was not a q u o ta system.
Its original purpose was to m ake special efforts to ensure that educational
and employm ent opportunities were open to those groups that h ad histor­
ically been shut out, provided they met the usual qualifications, and to
actively recruit them. Jensen states that he has supported this approach
from the beginning. However, he says that when this failed to yield enough
qualified m inority members, Affirm ative A ction was turned into a reverse
discrim ination quota. H e finds that to be unfair and simply wrong.
W hile that all sounds very morally uplifting, I ask Jensen whether a
genetic role in the Black-W hite average-IQ difference means th at de facto,
i f not de jure, segregation will be with us forever and that any attem pts to
produce truly integrated, quality education are doom ed to failure. Jensen
rejects my argument because he believes it contains two false premises.
First, quality education is not “ one size fits all” education. Instead, we now
have com puter technology to give every child an educational program
specifically tailored to abilities, regardless o f race, ethnicity, or social class.
We wouldn’t have to worry abo u t whether there were enough m em bers o f
any group in the honors classes, because in Jensen’s system there wouldn’t
be honors classes. Every student w ould be honored by being given his or
her best chance to succeed. Second, it has to be em phasized that the Black-
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W hite difference in average IQ is only slightly greater than the average d if­
ference in I Q that occurs between full siblings reared together. As a socie­
ty, we have no trouble dealing with that. T h e race difference is simply m ore
visible.
We also discuss dysgenics, that is, the decline in the average I Q (which
Jensen argues is taking place); eugenics (which Jensen favors, though on the
basis o f family choice rather than societal mandate); genetic engineering (a
possibility, and an acceptable one, he believes— again, on an individual
basis); population grow th (in Jensens view, the w orld’s number-one p ro b ­
lem, m ore than dysgenics) and its con trol (requiring som e government
role); im m igration (w hich he also believes should be regulated); and brain
drains an d brain gains, and what they will mean as society becomes m ore
and m ore dependent on an educated an d— in Jensens view— high-^ p o p u ­
lation.
We
conclude w ith Jensen’s th o u g h ts on how
three tenets o f
Jensenism — the failure o f com pensatory education, the heritability o f the
g factor, and the genetic component in the Black-W hite difference in aver­
age I Q — have held u p since his fam ou s 1969 article in the Harvard
Educational Review. M ore importantly, we discuss why it is not im portant to
Jensen whether he tu rn s ou t in the en d to have been righ t or wrong, only
that scientific research on these questions be allowed to advance.
M iele: S o far we’ve talked a lot ab o u t the science an d a little about
the history and p o litics o f the ra ce -IQ debate. N o w I want to talk
about policy, which fo r the m ost p a r t you’ve avoided. W hat is your
overall view o f the relationship between science and policy? D o you
think there is a general rule we sh o u ld follow, such as “Science and
politics don’t m ix” ?
Jensen: I have intentionally avoided policy questions in writing about
m ental abilities because I think o f the scientific research as distinct
from public policy. Policy concerns decisions abo u t how the knowl­
edge gained through research sh o u ld be used in ways that w ould
affect people’s lives. T h e acquisition o f factual knowledge should
stand ap art from policy. But to be effective, policy m aking must take
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into account our best factual knowledge ab o u t the alternatives under
consideration.
In the world o f practical affairs, any given policy decisions must
also take into account a num ber o f factors besides the relevant scien­
tific data. Som e o f these other considerations may be in conflict.
Policy decisions then emerge from weighing scientific knowledge
along with all the other, and at times conflicting, factors outside the
province o f science— ideals and goals; econom ic feasibility; tradi­
tional social, cultural, and religious values; an d the prevailing consen­
sus o f public opinion at a given time. Policy is often a m atter o f com­
promise.
M iele: But do you think policy questions that deal w ith human
beings have to be treated differently?
Jensen: Successful policies, no matter how well intended, sh ould not
be based on purely wishful thinking or on speculative an d untestable
philosophy. T h ey m ust recognize the reality principle, an d that is
where science plays an im portan t role. I believe this is w idely recog­
nized. In the case o f education, however, som e o f the government
decisions have simply ignored any research findings that d o not sup­
p ort the politically p o p u lar policies. T o o many politician s take
research results less seriously than purely p olitical considerations. The
popular m edia seldom help either, as they are also m ore politically
than scientifically oriented.
Miele: W h at you’ve just said leads us back to the three p o in ts in your
1 9 6 9 Harvard Educational Review article th at gave rise to the word
Jensenism: ( I ) the failure o f com pensatory education, ( 2 ) the evidence
for a genetic basis to I Q , and (3 ) the likelihood o f so m e genetic
com ponent in the Black-W hite IQ difference. T he first element
clearly involves an evaluation, even if a scientific one, o f public pol­
icy. Back in 1 9 6 9 , m ost educators and psychologists considered com­
pensatory education as a scientifically based m ethod to elim inate the
Black-W hite I Q difference.
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S o didn’t Jensenism at least straddle the line between science and
policy from the onset?
Jensen: I don’t believe I straddled the line because p o lic y itself can
be a test o f a theory. I f a course o f action is b a se d on defective
theory, it won’t work. It was the failure o f that policy, one in which
I believed at the tim e, th at was largely responsible fo r my becom ­
ing involved in the I Q
controversy. T h e re p o rt o f the U .S.
C o m m issio n on C ivil R ig h ts on the failure o f com pen satory ed u ­
cation p rogram s to raise the I Q an d scholastic achievem ent o f the
“ culturally disad van taged ” came as a shock to m e and to m o st
other educators. It clearly co n trad icted the expectations o f the
psych ological and education al th eories that prevailed in the 1 9 5 0 s
and 1 9 6 0 s.
T h is was immediately followed by the famous C olem an R eport,
com m issioned by C on gress in 1 9 6 6 . It looked at w hether per-pupil
expenditure, p u p il/teach er ratio, teacher qualifications, special serv­
ices, and the like really could explain regional, social class, and racial
group differences in p u p ils’ scholastic achievement. T h e report
showed that all these school variables together accounted for only
about 1 0 percent o f the variation in scholastic perform ance. T he rest
was attributable to p u p ils’ family background factors, som ething over
which the schools have no influence.
T h e clear-cut finding rang the alarm that som ething was seriously
wrong with the prevailing theory o f individual and g ro u p differences
in scholastic perform ance. Faced with this evidence, educational psy­
chologists could either reassess their shaken theory, or try to explain
away its failures with one excuse after another. F o r som e people, a
w ish-fulfilling theory can become an unshakable article o f faith, and
so there are some psychologists and educators who still advocate the
failed theories o f the past.
M iele: T h en let me turn to two o f the m ost im portan t policies—
E q u al O pportunity and Affirm ative A ction. W hat d o those term s
mean to you? W h at were your views on Equal O pportun ity and
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Jensen taking a break outside bis home. (February 2 0 0 2 )
A ffirm ative Action back in 1969? H ow has thirty years o f research
changed your opinions, i f at all?
Jensen: M y thoughts abo u t equal op p ortun ity haven’t changed at all.
I have always believed in equal op p ortun ity for every individual,
regardless o f sex, race, religion, national origin, or any other classifi­
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cation— provided that it is understood that ensuring equal o p p o rtu ­
nity for everyone doesn’t ensure that everyone will benefit equally
from the very same opportunity. To a large degree, we select our
opportunities, and opportunities select those with the necessary
mental maturity, special abilities, and proclivities to profit from them.
T h e aim o f public education should be to provide a sufficiently wide
range and variety o f different opportunities that all children can ben­
efit in the ways that will be m ost apt to serve them in adulthood.
Given these opportunities, each child’s particular abilities and pro­
clivities as dem onstrated by frequent assessm ents o f their perform ­
ance should guide their course through school.
Miele: A n d Affirmative Action?
Jensen: W hen the original concept o f A ffirm ative A ction was just
catching on in the 1 9 6 0 s it was not a quota system. T h a t only came
later. I approved two m ain facets o f its original intent, and I still do:
( I ) We sh o u ld make special efforts to ensure that historically under­
represented minorities are fully aware that educational opportunities
in colleges and universities, in job training program s, and in em ploy­
ment opportunities are open to all, provided they meet the usual
qualifications; and (2 ) colleges and universities, job training pro­
gram s, and employers sh ould actively seek ou t and recruit m inority
persons who could qualify by the usual standards, including the use
o f academ ic talent searches at the high sch ool level, special induce­
ments, and scholarships to encourage academ ically prom ising m inor­
ity students to go on to college.
Miele: A n d what about the “ quota” system you mentioned?
Jensen: T h a t only came about when the measures I described didn’t yield
as high a percentage o f qualified minority students or o f qualified job
applicants as was hoped for. T hen the program turned into one o f relax­
ing the selection standards for certain minorities in order to meet
Affirmative Action guidelines— in effect, a quota or reverse discrimina-
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tion system. Since there is usually only a limited num ber o f admissions
possible for a given institution, som e substantial num ber o f better-qual­
ified W hite and A sian applicants w ould be denied admission in favor o f
applicants who were designated as members o f underrepresented
minorities, m ostly Blacks and H ispanics. Such discrimination based on
race is patently unfair and an anathem a to those who were brought up
in an era that taught that racial discrimination is sim ply wrong. A nd it
is now apparent that there are certain tangible disadvantages to the sup­
p osed beneficiaries themselves resulting from this form o f reverse dis­
crimination. First, in the eyes o f many, it depreciates the merit o f those
m inority members who could have competed successfully without any
special dispensation. It can also lower the self-esteem o f those individ­
uals who come to realize that they were selected because o f their race,
n ot their ability. A n d biased selection procedures have a cascading effect
at later points in the career where less Affirmative Action is im ple­
mented. T h ose who weren’t qualified for entrance will experience only
failure and frustration as they try to climb up the ever more demanding
rungs o f the vocational or educational ladder.
M iele: But w ithout such program s, doesn’t the 1 5-po in t Black-W hite
difference in average I Q mean th at segregated schooling, de facto i f
n ot de jure, will be with us forever and that any attem pts to produce
truly integrated, quality education are doom ed to failure?
Jensen: N o, I don ’t agree. N o r d o I agree that there is any advantage
in de jure, or legally enforced, “ racial balance.” Parents should be able
to send their children to the sch ool o f their choice. I favor any m eas­
ures that would m axim ize free choice. It won’t lead to either com plete
segregation or com plete racial balance. I have repeatedly emphasized,
particularly in talks before educational organizations and in a recent
publication, th at quality education does not m ean the very same p ro ­
gram o f instruction for every child, but equal opportunity for all
children to receive a specific program tailored to their individual differences
in general ability and in special aptitudes. I especially stress the words
individual differences to emphasize th at these differences cut across all
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racial, ethnic, and social class groups. In a recent publication, I have
described the kind o f revolution in educational m eth ods with the
technology now available that I believe w ould best be able to provide
the op tim al educational experiences fo r virtually all children in the
school-age population.
M iele: B ut doesn’t a purely m eritocratic educational p olicy like the
one you suggest mean that there w ould be only token Blacks in
advanced or honors classes in grade sch ool and high school, and at
the m ost selective universities?
Jensen: In the system I have proposed there wouldn’t be honors classes
in grade school or high school. W ith individualized, com puter-assist­
ed instruction, and sm all group interactions with teachers, there
would still be a wide range o f individual differences, b u t every pupil
wouldn’t be moving in lockstep on one an d the same academ ic track.
We can’t eliminate individual differences, but we can adapt
instruction optimally to take account o f individual differences. W hen
it comes to adm ission to colleges and universities, the selection crite­
ria will be based largely on students’ achievements in academ ic sub­
jects, o f course, because that’s what college is about. A n d colleges will
differ greatly, as they d o now, in their selectivity on academ ic criteria
and on the relative w eights given to oth er selection criteria. I f there
are racial, ethnic, social class, or any oth er kind o f g ro u p differences
in the p roportion s o f the groups that m eet these selection criteria, so
be it, as lon g as every applicant, regardless o f group m em bership or
background, has been evaluated objectively on his or her own indi­
vidual achievements.
M iele: O kay, su p p o se you were ap p o in ted n ot Secretary o f
Education, but Education Czar. You have complete dictatorial power
over A m erica’s entire educational system from preschool to postdoc­
toral program s.
W h at w ould you d o and how much w ould it be based on the three
tenets o f Jensenism— the failure o f com pensatory education, the her-
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liability o f the g factor, and the existence o f some genetic com ponent
in the Black-W hite I Q difference?
Jensen: I find the very idea o f a federally appointed “ Education
C z a r” unappealing, undem ocratic, an d contrary to what I believe.
Free enterprise in public education, with variety and com petition
am on g m ethods o f schooling, is m ore likely to result in successful
p rogram s than a centrally dom inated educational system . In the arti­
cle I previously referred to, I described the kinds o f innovations in
schooling that I think would best take account o f the very wide range
o f individual differences in learning abilities in our sch ool popula­
tion— a wide range exists within every racial or ethnic group. It’s a
program I would suggest even in countries or com m unities that are
hom ogeneous racially or socially.
T h e key point I want to make is th at full siblings w ithin the same
family, on average, differ in I Q by ab o u t as much (aroun d 12 I Q
p o in ts) as the average difference between Blacks and W hites o f the
sam e social class. (E quatin g the two grou ps for social class reduces
the overall 15-poin t Black-W hite average IQ difference by about
three points). M o st people are surp rised by this, bu t it’s a fact. A t
least h a lf o f the popu lation variation in I Q is within fam ilies.
T h e reason group differences are the focus o f so m uch attention
is because certain grou p characteristics are highly visible. S o the high­
ly publicized social and political problem s o f education are com ­
m only seen as involving group differences. But the real problems o f
education exist at the level o f individual differences, an d these would
exist even i f there were no racial or oth er group differences. Let’s not
forget that the grou p differences are ju st aggregated individual d if ­
ferences and should be taken account o f in the sam e way. N othing I
have discovered about the science o f m ental ability contradicts any­
thing I believe ethically about the p rim acy o f the individual over the
group.
M iele: D o you think there’s any real-w orld evidence o f dysgenics, a
genetic “ dum bing-dow n” o f the A m erican population?
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Jensen: T h e matrix o f possible causes is way too com plex and too
poorly understood to serve as a reliable basis for inferring anything
about the quality o f the nation’s gene p o o l or average level o f g at any
point in time. You’d have to look at the trend, from decade to decade,
in the birthrates in different segments o f the population that differ
in I Q or any other trait that may be o f interest to you.
T h e proper analysis is to examine the number o f live births per
woman (including th ose with no children, and regardless o f their
marital statu s) at approxim ately the end o f the child-bearing years,
say, age 4 5 . Such data are available from the U.S. Census. We know
that the number o f years o f education com pleted by adult women
correlates about 0 .6 0 with their IQ s. T h e Census data show higher
birthrates at the lower levels o f education than at the higher levels,
for both Blacks and W hites. But there is a greater disparity in
birthrates between p oorly educated and well-educated Blacks than is
true for W hites. I f this trend continues over a number o f generations,
the Black and W hite populations will be pulled increasingly further
apart in average IQ . A n d the same thing will happen fo r any other
traits that are correlated with educational level and IQ .
Miele: But I ’ve heard very competent geneticists and dem ographers
dism iss these claims o f dysgenic doo m because they don ’t take into
account the people at the very low end o f the I Q distribution who
don’t reproduce.
Jensen: T h a t percentage is actually very sm all compared to the statis­
tics I’ve ju st given. T h e data in the study m ost frequently cited to
make that point were gathered in a sm all, m iddle-to-upper-m iddleclass, predom inantly W h ite city— K alam azoo, M ichigan. S o they are
not representative o f the U .S. population o f today.
Miele: T h e armed forces are one segm ent o f American society for
which we have extensive information. T h ere were problem s, and even
race riots, during the V ietnam War years. But the m ilitary have prob­
ably been the m ost successful sector o f American society in getting
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over racial segregation. D oes that m ean that achieving full integration
requires autocratic m easures?
Jensen: I agree the arm ed forces have been successful, not because
they are autocratic, b u t because they are m eritocratic. T h e armed
forces are not an A ffirm ative A ction employer. T h e m ilitary select
their personnel on the sam e criteria, regardless o f race. A nd Congress
has m andated that th o se below the tenth percentile (th at is, with an
I Q o f about 8 0 ) are n ot eligible fo r military service. T h e military
evenhandedly use a test o f m ental ability, the A rm ed Services
V ocation Aptitude Battery (A SV A B ), to assign enlisted personnel to
the many different training program s that require different levels o f
aptitude for acquiring specialized knowledge and skills. And the
A SV A B is a very g o o d measure o f g, which it must be in order to suc­
cessfully predict success or failure in the various training programs.
M iele: T h e U n ited States substantially reduced welfare programs,
effectively elim inating the political right to public assistance. Political
liberals tell us this is not only inhum ane but will have disastrous
results should the econom y take a serious downturn. But political
conservatives tell us the marketplace will take care o f all this if gov­
ernm ent just gets o u t o f the way. Given the im portance you attach to
g, what do you see as the result o f eliminating or severely reducing
welfare?
Jensen: M y guess is th at it will be im possible to elim inate welfare, or
at least it is incom patible with having a humane society in which peo­
ple are not allowed to fall below som e minimum decent standard o f
living. In a humane society, the lim itations on the grow th o f the seg­
m ent o f a nation’s population that will be in need o f welfare will
depend on m easures taken to greatly diminish the birthrate in that
segm ent o f the population . T h e correlation between parents and
their offspring in g an d other im portan t traits, whatever the cause,
m akes it statistically predictable which parents will contribute the largest
p roportion o f the welfare dependents o f the next generation— those
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at the lower 10 or 15 percent o f the distribution o f g in the general
population. I emphasize that this is a statistical estimate, and applies
to any particular pair o f parents only with som e quite large probable
error. But in psychology we can statistically speak o f a persons being
“ at risk” for, say, educational failure, delinquency, or welfare d e p en d ­
ency ju st as in m edical practice one can identify those who are sta tis­
tically “ at risk” for obesity, diabetes, heart disease, or cancer.
M iele: T h en do you consider som e form o f eugenics to be feasible
and ethically acceptable?
Jensen: Yes, but m ore ethical than feasible in the present clim ate o f
public opinion. N egative eugenics is already available on a personal,
individual basis, in the form o f genetic counseling o f m arried co u ­
ples who wish to m inim ize the risk o f having a child with a high lia­
bility o f som e genetic disease. Few people object to that.
Singapore is the only country I know o f that has instituted m eas­
ures intended to prom ote positive eugenics, essentially by giving tax
credits to parents who are college graduates for every child they have,
and awarding college scholarships to all o f their offspring who can
qualify for adm ission. T hese an d other such measures sh ould, I
think, be taken in other countries as well, provided they do n ot co n ­
flict with the need for zero p op u lation growth o r even a birth rate
that w ould reduce the present size o f the w orld’s popu lation .
R educin g popu lation seems m ore urgent to m e than eugenics p er se.
But unless people in the upper h a lf o f the bell curve for g have at
least as many offsp rin g as th o se o f the lower half, there will
inevitably result a dysgenic trend in the overall ability level and the
educability o f the population as a whole.
A dam Sm ith was correct, I believe, when he wrote in The Wealth of
Nations that a country’s m ost im portan t natural resource is the level o f
educated ability o f its population. T h is depends in large measure on
the overall level o f g as well as on the quality o f the educational sy s­
tem and the cultural environment, which in turn reflect the society’s
level o f g. T h e distribution o f g in a society and the environmental,
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cultural, and educational conditions that affect the outward m anifes­
tations o f g are not independent forces. Generally, environmental
conditions are created by people, not im posed on them, and g is one
o f the crucial factors determ ining that creation.
Miele: T h en w hat about the question o f p op u lation in general?
Jensen: T h e grow th o f populations worldwide, especially in the T h ird
W orld, is by far the m ost serious problem we have to face. Population
growth certainly cannot continue indefinitely. I t’s even questionable
whether the present world population o f six billion already exceeds
the earths carrying capacity. O n e wonders i f population grow th will
continue to the point that the human m isery it causes is so massive
and so p rofo u n d as to be utterly unconscionable and intolerable. It
has already reached that p oin t in certain p arts o f the world. A s far as
I know, C hina is the only country that has officially recognized this
problem and actually has taken measures to d o something abo u t it,
with its policy o f one child per family. T h ey know that only enforce­
ment o f such measures, however draconian, th at restrict population
growth will save them. T h e totalitarian con ditions that are appar­
ently needed to accomplish this goal seem tolerable if one considers
the eventual consequences o f ignoring the problem . It seems the less­
er o f two evils, considering the consequences o f overpopulation.
O verpopulation pressure in a nation not only reduces the quality o f
life and creates personal m isery for millions, b u t it is also a threat to
neighboring countries and even to other countries worldwide. It may
engender the political conditions that could lead to global war.
Miele: But whether the econom y is in a b o o m or a decline, there is a
demand for high-tech professionals and for agricultural and dom estic
workers. D o esn ’t that mean the U nited States needs more im m igrants,
not fewer?
Jensen: N o F irst W orld country can expect to have an open border
with a T h ird W orld country w ithout serious risk to its own economy
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and quality o f life. As for em ploym ent dem ands, it seems unreason­
able that unskilled or sem i-skilled workers fro m other countries
should be brought in if they take jobs that co u ld be filled from a
country’s own citizens. Low -skill work could probably be perform ed
by many people who would otherwise need to rely on welfare. A s to
the kinds o f highly skilled workers— engineers, scientists, physicians,
and the like— who are usually in sh o rt supply in a highly technolog­
ical society, the world actually resembles a free market to a large
extent, with high ability generally following the laws o f supply and
demand, within nations and across national borders.
T h is econom ic demand for higher levels o f professional and tech­
nical skills naturally makes for brain drains in som e countries and
brain gains in others. I read not lon g ago, for example, that India has
the largest brain drain o f any large country, while a few other coun­
tries, including the U nited States, are beneficiaries o f a corresponding
brain gain. A t about the sam e time I read a report from the
Educational Testing Service saying that the m inority group getting the
highest S A T scores in recent years are the children o f immigrants from
India. T he supply o f highly educated, technical talent in India exceeded
the demands o f their industry and economy, but has helped to fill the
otherwise unm et demand for engineers and com puter scientists in the
U nited States. T h e same thing is seen in many other First W orld coun­
tries. T h is seems to be inevitable in the m odern world.
M iele: A s genetic screening and gene replacement techniques, even
cloning, becom e economically m ore affordable, do you see b etter-off
couples signing up for that so rt o f thing, even taking out loans i f
necessary? A nd i f the U nited States and other m ajor nations ban
these procedures, won’t a black m arket spring u p in Cuba (which
actually has been a leader in som e aspects o f biotech) or on som e
sm all offshore nation, or via cyberspace, as is the case with certain
“ designer d rugs” ?
Jensen: I can’t predict the future, but it is likely that public opinion
and government policies in various countries will differ in their atti­
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tudes toward eugenics and, i f their population growth rate is no longer
threatening, som e countries m ay decide to d o as Singapore has done,
or som ething similar. I f an d when that happens, it will highlight
A dam S m ith s words that I ju st mentioned. N ational populations will
begin to differ more than they do now, n ot only in behavioral quali­
ties but in many aspects o f health as well. I’m talking about large-scale
effects over a period o f several generations, n ot about cloning, or indi­
viduals’ personal positive eugenics. T h o se things may happen, but they
would be a drop in the bucket, and a highly suspect one at that. They
wouldn’t make a significant difference, except perhaps in the number
o f questionable characters who took advantage o f some people’s over­
weening am bition for their offspring.
Sir Francis Galton’s original idea o f eugenics, which he defined in
his autobiography as “the scientific study o f the biological and social
factors which improve or im pair the inborn qualities o f human
beings and o f future generations,’’ didn’t include the kinds o f
biotechnology that may one day be possible, nor did it rule them out.
Miele: T h en are we looking at a m ulti-tiered “ brave new w orld” that
is m eritocratic at the high end and in the m iddle, but the low end can
only hope that some form o f welfare is provided?
Jensen: Every complex society in history has been multi-tiered. Ours
is no different in that respect. A s a society becom es more technolog­
ical and information-intensive, however, the g factor com es increas­
ingly into play in determ ining where people and groups com e out in
the hierarchy o f prestige an d rewards. In general, societies have valued
and rewarded m ost those individuals who can do things that very few
others can d o and have rewarded least those who can only d o things
that many other people could d o at least as well. W ith the increasing
complexity o f the functions needed for a society to m aintain a com ­
petitive p osition in the m odern world, the g factor and its m anifesta­
tions in the workplace becom e more salient and more highly valued.
H ence those in the lower quarter o f the distribution o f g in the p o p ­
ulation are at an increasingly greater risk for lacking the knowledge
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and skills that are m ost in dem and in our m odern society, and may
even lack the requisite educability for acquiring them. To the extent
that certain socially identifiable groups w ithin the population differ
on average in this respect, this problem has political overtones.
M iele: W h at advice, then, can you give to all those in the U n ited
States and around the world who are in that group? W hat can you say
to those who because o f genes, environment, or accident feel they are
being left behind by the “ brave new world” so many others are build­
ing and enjoying?
Jensen: I think the progress o f civilization benefits everyone. N o one
is really being “left out” o f whatever benefits com e from science and
invention, except for som e pockets o f deplorable destitution in parts
o f the T h ird W orld. In every society there has always been a wide
range o f individual differences in material advantages, wealth, abili­
ties, talents, looks, and sheer luck. An individual has little control
over some o f these things.
M y philosophy has been sim ply to try and d o one’s best with what
one has to work with, and that in itself can bring satisfaction, know ­
ing that you have applied your best effort to som ething, to have m et
responsibilities, and to have discharged your duties and dealt with
others honorably. T h is becom es its own reward.
T hat, in fact, is the basic teaching o f the Bhagavad Gita, which I have
long enjoyed reading in m any different translations, though I am not
a H indu or even a religious person. In one o f the M ahatm a G andh i
m useums in India I recall seeing a letter on display that he h ad w rit­
ten to som eone in which he said, “W hat you are doing m ay n ot be
im portant, but it is very im portan t that you d o it.” T h a t attitude can
often help one not feel discouraged, but instead carry on with what
one believes has to be done. H aving ideals, perhaps more than any­
thing else, m akes life seem worthwhile.
M iele: L o ok in g back at the three tenets o f Jensenism — the failure o f
com pensatory education, the heritability o f the g factor, and the
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genetic factor in the Black-W hite difference in average IQ — are you
m ore or less confident o f each o f them than you were in 1969 when
you published your fam ous article in the Harvard Educational Review?
Jensen: As to the failure o f com pensatory education, I think the evi­
dence accum ulated since 1 9 6 9 shows that purely psychological and
educational m anipulations have relatively little i f any enduring effect
on individuals’ level o f g. R egarding the heritability o f g, it has proven
to be the m ost highly heritable com ponent o f hum an mental abili­
ties. T h e m o st difficult question to resolve scientifically— and the
one that causes the m ost controversy, o f course— is the role o f genes
in the Black-W hite IQ difference. M any different lines o f evidence
are consistent with the D efault H ypothesis that both genes and envi­
ronment play a p art in the overall mean Black-W hite difference in g,
ju st as they d o fo r individual differences w ithin both populations.
Predictions fro m the D efault H ypothesis have been tested and they
have held up. T h e purely environmental or “ culture-only” theory, on
the other hand, has had to fall back on series o f ad hoc hypotheses.
T h ey lack any underlying theoretical basis and are often inconsistent
with each other, since each one was invented to explain som e single
phenomenon.
I f there’s anything on which my judgment has changed significant­
ly since 1 9 6 9 ,
it is the scientific value o f typical I Q
tests.
Psychological tests are limited by the fact that they do not provide
absolute scales, that is, those that have a true zero point and equal
intervals throughout their range. A s is well known in the physical sci­
ences, the m athematical, and n ot just statistical, analysis o f data is
much greater with measurements based on absolute, or ratio-property,
scales. T h ese are virtually absent in psychological measurement.
There’s no doubt, however, that I Q tests and many other conventional
psychological tests have real practical value. T h e y are unquestionably
valid predictors o f certain kinds o f perform ance in education and
employment, and can be m ost useful in educational selection, and in
hiring and prom otion decisions.
SCIENCE
AND
POLICY
189
A s I’ve worked on my book-in-progress on m ental chronometry
(the real-time measurement o f cognitive processes while they are
goin g on), it has becom e ever clearer to me that the standard tests
used in psychology only allow us to see “through a glass darkly.” I
now believe the precise response-time measures o f cognitive processes
will p u t psychology and the study o f human differences on a m uch
m ore scientific basis, comparable to that o f the physical sciences. T h e
study o f human m ental abilities is now going directly into the brain,
and fo r this to progress apace we will need to m easure behavior in
physical units, nam ely time m easured in m illiseconds. T im e is a n at­
ural scale o f m easurement for m any mental processes. I view this line
o f research, which has great poten tial for brain research in relation to
the questions o f differential psychology, as the extension o f what can
be called the G alton paradigm. It is yet another case where Sir Francis
G alto n (1 8 2 2 —1 9 1 1 ) was on the righ t track to begin with. T h e field
o f scientific psychology erred in straying from it fo r so long.
M iele: Finally, is there anything else you'd like to say, modify, or co r­
rect?
Jensen: All I will say in conclusion is that it won’t m atter to me in the
long run if what I have said in these interviews eventually turns o u t
to be proven either true or false, right or wrong. It is only what I
think at present, b ased on my own research and all m y reading, study,
and thinking about the subjects you have questioned m e about. I have
tried to express m y answers clearly and forthrightly. W hether I ’m
right or wrong in any particular instance isn’t the really im portant
thing. W hat is im portan t is that scientific research on these m atters
sh ould be encouraged and allowed to advance unfettered.
Finally, let me say that though I have been interviewed about m y
work a great many tim es in the la st thirty years, by figures such as
Jo sep h Alsop, D an Rather, Phil D on ah ue, and M ike Wallace, to nam e
a few, I haven’t m et another interviewer who came as well prepared
and as sharply in form ed on all the topics o f our discussion as you
190
INTELLIGENCE,
RACE, A N D
GENETICS
have been. I ’m rather am azed. I appreciate it, and I thank you very
much.
M iele: T h e n thank you fo r giving so generously o f your time, for
going on record in such depth and breadth, and for those extremely
kind words.
Further Reading
Jensen describes in detail his views on Affirmative A ction , and on how the educational
system should be changed to better meet individual differences, in: Jensen, A . R . (1997a).
Spearm an’s g and the problem o f educational equality. Oxford Review of Education, 1 7 (2),
1 6 9 - 1 8 7 ; and in: Jensen, A. R . (1 9 9 7 b ). T h e g fac to r in the design o f education. In
Sternberg, R . J., and W illiams, W. M . (E ds.), Intelligence, instruction, and assessment. Hillsdale,
N J: Erlbaum . (T h e latter b o o k also contains essays by other, equally distinguished con­
tributors, many o f whom express views very different from Jensen’s.)
T h e m ost recent biography o f the founder o f differential psychology, eugenics, men­
tal chronometry, and the L on d on Sch ool o f psychology ( o f which Jensen is the foremost
living exponent) is: Gillham, N . W. (2 0 0 1 ). A life of Sir Francis Gabon. N e w York: Oxford
University Press. (G alton also pioneered the use o f tw ins in scientific stud ies aimed at
assessing the relative effects o f nature and nurture.)
For m ore inform ation on these subjects, see the bibliography o f Jensen’s publications
in Appendix A.
APPENDIX A
BIBLIOGRAPHY OF
A R T H U R R. J E N S E N
1955
1. S y m o n d s, P. M ., an d Jensen, A . R . ( 1 9 5 5 ) . A review o f six tex tb o o k s in edu ­
catio n al psychology. Jou rnal o f Educational Psychology, 46, 5 6 —6 4 .
1956
2. Jensen, A . R . ( 1 9 5 6 ) . A g g re ssio n in fan tasy an d overt behavior. U n pu b lish ed
d o c to ra l dissertation , C o lu m b ia University, N e w York.
1957
3. Jensen, A . R . ( 1 9 5 7 ) . A g gressio n in fan tasy an d overt behavior. Psychological
Monographs, 71, N o . 4 4 5 , W h o le N o . 16.
4. Jensen, A . R . ( 1 9 5 7 ) . A u th oritarian attitu d e s an d personality m aladjustm ent.
Jou rn al o f Abnormal and Social Psychology, 5 4 , 3 0 3 —3 1 1 .
5. P ope, B „ an d Jensen, A . R . ( 1 9 5 7 ) . T h e R o rsc h ach as an index o f path ological
thinking. Journal o f Projective Techniques, 2 1, 5 9 —6 2 .
1958
6. Jensen, A . R . ( 1 9 5 8 ). Personality. Annual Review of Psychology, 9, 2 9 5 —3 2 2 .
7. Jensen, A . R . ( 1 9 5 8 ). T h e M au d sle y P erso n ality Inventory. Acta Psychologica, 14,
3 1 2 - 3 2 5 . R eprin ted in: Savage, R . D . (E d .), Readings in Clinical Psychology.
Pergam on Press, 1 9 5 8 .
8. S y m o n d s, P. M ., an d Jensen, A . R . ( 1 9 5 8 ) . T h e predictive sign ifican ce o f fan ­
tasy. American Journal of Orthopsychiatry, 2 8 , 7 3 —8 4 .
191
APPENDIX
192
A
1959
9.
Jen sen , A. R . ( 1 9 5 9 ) . T h e reliability o f projective tech n iques: Review o f the lit­
erature. Acta Psychologica, 16, 3 - 3 1 .
10. Jen sen , A. R . ( 1 9 5 9 ) . The reliability of projective techniques: Methodology. A m sterdam :
N o r th -H o lla n d P u b lish in g Co. Pp. 3 2 —6 7 .
11. Jen sen , A. R . ( 1 9 5 9 ) . A statistical n o te o n racial d ifferen ces in the Progressive
M a t r ic e s . Journal o f Consulting Psychology, 2 3 , 212..
12. Jen sen , A. R . ( 1 9 5 9 ) . Review o f the T h e m a tic A p p e rc e p tio n Test. In O . K.
B u ro s (E d .), Fifth mental measurements yearbook. H ig h lan d Park, N J: G ry p h o n
P re ss. Pp. 3 1 0 —3 1 3 .
13. Jen sen , A. R . ( 1 9 5 9 ) . Review o f th e F a m ily R elatio ns T e st. In O. K . B u ros
( E d .) , Fifth mental measurements yearbook. H ig h la n d Park, N J : G ryphon P ress. P p .
227-228.
14. Jen sen , A. R . ( 1 9 5 9 ) . Review o f Perceptual processes and mental illness, b y H . J.
E ysen ck , G . W. G ran ger, and J. D . B rengelm ann. Jou rn al o f Nervous and Mental
Diseases, 128, 4 6 9 —4 7 1 .
1960
15. Jen sen , A. R . ( I 9 6 0 ) . H o listic p e rso n ality . Review o f Understanding personalities,
b y R . Leeper and P. M a d iso n . Contemporary Psychology, 5, 3 5 3 —3 5 5 .
16. Jen sen , A. R . ( I 9 6 0 ) . S o m e criticism s o f autom ated teaching. California Jou rn al
o f Instructional Improvement, 3, 32—3 5 .
17. Jen sen , A. R . ( I 9 6 0 ) . Teaching m ach in es an d individual differences. Automated
Teaching Bulletin, I, 1 2 —16. R eprin ted in: Sm ith , W. I., an d M o ore, J. W. (E d s .),
Programmed learning. N e w York: Van N o s tr a n d , 196 2 . P p . 2 1 8 —226.
1961
18. Jen sen , A. R . ( 1 9 6 1 ) . O n the re fo rm u latio n o f in h ib itio n in H u ll’s sy stem .
Psychological Bulletin, 3 8 , 2 7 4 —2 9 8 .
19. Jen sen , A. R . ( 1 9 6 1 ) . Learning ab ilitie s in M exican-A m erican and A n g lo A m erican children. California Journal o f Educational Research, 12, 1 4 7 —1 59.
2 0 . S y m o n d s, P. M „ a n d Jensen, A. R . ( 1 9 6 1 ) . From adolescent to adult. N e w Y ork:
C o lu m b ia U niversity Press. Pp. viii + 4 1 3 .
1962
2 1 . Jen sen , A. R . ( 1 9 6 2 ) . T h e von R e s t o r f f isolatio n e ffect w ith m inim al re sp o n se
learn ing. Journal o f Experimental Psychology, 6 4 , 123—1 2 5 .
APPENDIX A
193
2 2 . Jensen, A . R . ( 1 9 6 2 ). A n em pirical theory o f the serial-position e ffe c t. Journal
of Psychology, 5 3 , 1 2 7 —1 4 2 .
2 3 . Jensen, A . R . ( 1 9 6 2 ). T e m p o ra l and sp atial effects o f serial p o sitio n . American
Jou rnal o f Psychology, 75, 3 9 0 - 4 - 0 0 . R e p rin ted in: Slam ecka, N . J. (E d .), Hum an
learning and memory: Selected Readings. N e w Y ork: O x fo r d U niversity P ress, 1 9 6 7 .
Pp. 1 1 7 - 1 2 4 .
2 4 . Jensen, A . R . ( 1 9 6 2 ). Is the serial p o sitio n curve invariant? British Jou rnal of
Psychology, 5 3 , 1 5 9 —1 6 6 .
2 5 . Jensen, A . R . ( 1 9 6 2 ). T ran sfe r between paired -asso ciate and serial learning.
Jou rnal of Verbal Learning and Verbal Behavior, I, 2 6 9 —2 8 0 .
2 6 . Jensen, A . R . ( 1 9 6 2 ) . S p e llin g errors an d the serial p o sitio n effect. Jou rnal of
Educational Psychology, 5 3 , 1 0 5 - 1 0 9 . R e p rin te d in: O tto , W., an d K oenke, K.
(E d s .), Readings on corrective and remedial teaching. B o sto n : H o u g h to n -M ifflin , 1 9 6 9 .
Pp. 346-352.
2 7 . Jensen, A . R . ( 1 9 6 2 ) . E xtraversión , neurotxcism , and serial learning. Acta
Psychologica, 2 0 , 6 9 —77.
2 8 . Jensen, A . R . ( 1 9 6 2 ). T h e im provem ent o f ed u catio n al research. Teachers College
Record, 6 4 , 2 0 —2 7 . R e p rin te d in: Education Digest, 1 9 6 3 , 2 8 , 18—2 2 .
2 9 . Jensen, A . R . ( 1 9 6 2 ). R eview o f Programmed learning: Evolving principles and industri­
al applications. Foundation f o r Research on H um an Behavior, edited by J. P. L ysaugh t.
Contemporary Psychology, 7, 3 3 .
3 0. Jensen, A . R . ( 1 9 6 2 ). R ein forcem en t p sy c h o lo g y and individual differences.
California Jou rnal of Educational Research, 13, 1 7 4 —1 7 8 .
3 1. Jensen, A . R ., and Blank, S . S . ( 1 9 6 2 ) . A sso c iatio n w ith ordinal p o sitio n in seri­
al rote-learnin g. Canadian Jou rn al of Psychology, 1 6, 6 0 —63.
32. Jensen, A . R ., C ollin s, C . C ., an d V reeland, R . W . ( 1 9 6 2 ) . A m ultip le S - R ap p a­
ratus fo r h um an learning. American Journal o f Psychology, 75, 4 7 0 —4 7 6 .
1963
3 3. Jensen, A . R . ( 1 9 6 3 ). S e ria l rote-learning: In crem en tal or all-or-none? Quarterly
Journal o f Experimental Psychology, 15, 2 7 —3 5 .
34. Jensen, A . R . ( 1 9 6 3 ). L e a rn in g abilities in retarded, average, and g ifte d children.
M errill-Palmer Quarterly,
9,
1 2 3 —140. R e p rin te d in: D eC ecco, J. P. (E d .),
Educational technology: Reading in programmed instruction. N e w York: H o lt, R in eh art,
and W in sto n , Inc., 1 9 6 4 . P p . 3 5 6 —3 7 5 .
3 5. Jensen, A . R . ( 1 9 6 3 ). L e a rn in g in the p re sch o o l years. Journal of Nursery Education,
18, 1 3 3 —1 3 9 . R e p rin ted in: H a rtu p ,W . W., an d Sm oth ergill, N a n c y L . (E d s.),
APPEN D IX A
194
The young child: Reviews of research. W ash in gton , D C : N a tio n a l A sso ciatio n fo r the
E d u cation o f Y o u n g Children, 1 9 6 7 . P p. 1 2 5 —1 3 5 .
3 6 . Jensen, A. R „ an d R oden, A. ( 1 9 6 3 ) . M e m o ry sp a n an d the skew ness o f the
serial-po sitio n curve. British Jou rn al o f Psychology, 5 4 , 3 3 7 —3 4 9
3 7 . Jensen, A. R ., an d Rohwer, W. D „ Jr. ( 1 9 6 3 ) . V erb al m ediation in p a ire d -a sso ­
ciate and serial learning. Journal of Verbal Learning and Verbal Behavior, I, 3 4 6 —3 5 2 .
3 8 . Jensen, A. R ., an d Rohwer, W. D ., Jr. ( 1 9 6 3 ) . T h e effect o f verbal m e d iatio n on
the learning an d retention o f paired -asso ciates by retarded adults. American
Journal of M ental Deficiency, 6 8 , 8 0 —8 4 .
1964
3 9 . Jensen, A. R . ( 1 9 6 4 ) . T h e R o rsch ach technique: A re-evaluation. Acta Psychologica,
22, 6 0 -7 7 .
4 0 . Jensen, A. R . ( 1 9 6 4 ) . Learn in g, briefly. Review o f Learning: A survey of psycholog­
ical interpretations, b y W. F. H ill. Contemporary Psychology, 9, 2 2 8 —2 2 9 .
1965
4 1 . Jensen, A. R . ( 1 9 6 5 ) . A n ad jacen cy effect in free recall. Quarterly Jou rn al of
Experimental Psychology, 1 1, 3 1 5 —3 2 2 .
4 2 . Jensen, A. R . ( 1 9 6 5 ) . R ote le arn in g in retarded ad u lts and n orm al children.
American Jo u rn al of Mental Deficiency, 6 9 , 8 2 8 —8 3 4 .
4 3 . Jensen, A. R . ( 1 9 6 5 ) . Individual Differences in Learning: Inteference Factor. C oop erative
Research P ro ject N o . 1867, U .S. O ffice o f E ducation . Pp. I —160.
4 4 . Jensen, A. R . ( 1 9 6 5 ) . Scorin g the S tr o o p T e s t. Acta Psychologica, 2 4 , 3 9 8 —4 0 8 .
4 5 . Jensen, A. R . ( 1 9 6 5 ) . Review o f the M au d sley P erson ality Inventory. In O . K.
Buros (E d .), Sixth mental measurements yearbook. H ig h la n d Park, N J: G ry p h o n
Press. Pp. 2 8 8 —2 9 1 .
4 6 . Jensen, A. R . ( 1 9 6 5 ) . Review o f the R orschach T est. In O. K. Buros (E d .), Sixth
mental measurements yearbook H ig h lan d Park, N J: G ry p h o n Press. Pp. 5 0 1 —5 0 9 .
Reprinted in: Bracht, G . H ., H o p k in s, K., and Stanley, J. C . (E ds.), Perspectives in
education and psychological measurement. N e w York: Prentice-H all, 1972. Pp. 2 9 2 — 3 1 1 .
4 7 . Jensen, A . R . ( 1 9 6 5 ) . Review o f the M ak e a P icture S to ry Test. In O . K . B uros
(E d .), Sixth mental measurements yearbook. H ig h lan d Park, N J: G ryp h on P re ss. Pp.
46 8 -4 7 0 .
4 8 . Jensen, A. R „ an d Rohwer, W. D ., Jr. (1 9 6 5 ). Syntactical m ediation o f serial and
paired-associate learning as a fu n ction o f age. Child Development, 3 6, 6 0 1 —6 0 8 .
4 9 . Jensen, A. R ., an d Rohwer, W. D „ Jr. ( 1 9 6 5 ) . W h a t is learned in serial le arn ­
ing? Journal o f Verbal Darning and Verbal Behavior, 4, 6 2 —7 2 . R eprin ted in: Slam eck a,
195
APPENDIX A
N .J. (E d .), H u m an learning an d memory. N ew Y o rk : O x ford U n iversity Press,
1 9 6 7 . Pp. 9 8 - 1 1 0 .
5 0 . Battig, W. F., A llen, M ., an d Jen sen , A. R . ( 1 9 6 5 ) . Priority o f free recall o f
newly le arn ed item s .Journal o f Verbal Learning and Verbal Behavior, 4, 1 7 5 —179.
1966
5 1 . Jensen, A. R . ( 1 9 6 6 ) . T h e m easurem ent o f reactive inhibition in humans.
Journal of General Psychology, 7 5 , 8 5 —9 3 .
5 2 . Jensen, A . R . ( 1 9 6 6 ) . So cial c lass and percep tual learning. Mental Hygiene, 5 0,
2 2 6 —2 3 9 . R e p rin te d in: R o g e rs, D oroth y (E d .), Readings in child psychology. N ew
York: B r o o k s-C o le Publish in g C o ., 1969.
5 3 . Jensen, A . R . ( 1 9 6 6 ) . In d iv id u al differences in concept learn in g. In H .
K lausm eier a n d C . H arris ( E d s .) , Analyses of concept learning. N ew Y o rk : M errill,
1 9 6 6 . Pp. 1 3 9 —1 5 4 . R ep rin ted in: Butcher, H . J., an d Lom ax, L ., R e ad in g s in
hum an in telligen ce. L ondon: M eth u en , 197 1 . P p . 1 0 0 —114.
5 4 . Jensen, A. R . ( 1 9 6 6 ) . C um ulative deficit in c o m p e n sa to ry education. Journal of
School Psychology, 4, 3 7 —47.
5 5 . Jensen, A. R . ( 1 9 6 6 ) . Verbal m e d iatio n and e d u c a tio n a l potential. Psychology in
the Schools, 3, 9 9 —1 09. R e p rin te d in: Torrance, E . P., and W hite, W . F. (E d s.),
Issues and advances in educational psychology. (2 n d E d A
Itasca, IL : F. E . Peacock,
1 9 7 5 . Pp. 1 7 5 - 1 8 8 .
5 6 . Jensen, A. R . ( 1 9 6 6 ) . C o n ce p tio n s and m isc o n c ep tio n s about verbal m ediation .
In M . P. D o u g la s (E d .),
Claremont Reading Conference, T h irtieth Y earbook,
C larem on t G rad u a te School. P p . 1 3 4 —141.
5 7 . Jensen, A. R . ( 1 9 6 6 ) . Intensive, detailed, exhaustive. Review o f Paired-associates
learning: The role o f meaningfulness, similarity andfam iliarization, by A. E . G o s s and C.
F. N o d in e . Contemporary Psychology, 11, 3 7 9 —3 8 0 .
5 8 . Jensen, A. R ., an d Rohwer, W . D ., Jr. (1 9 6 6 ). T h e S tr o o p C o lo r-W o rd Test: A
review. Acta Psychologica, 2 5 , 3 6 9 3 .
1967
5 9 . Jensen, A . R . ( 1 9 6 7 ) . V arieties o f individual d iffe ren c e s in learning. In R . M .
G agne (E d .), Learning and individual differences. C o lu m b u s, O H : M e rrill. Pp.
1 17—1 35. R e p rin te d in: R ow eton , W. E. (E d .), H um anistic trends in educational psy­
chology. N e w Y o rk : X erox C o., 1 9 7 2 .
6 0 . Jensen, A . R . ( 1 9 6 7 ) . E stim atio n o f the lim its o f h eritability o f traits b y com ­
parison o f m o n o zy g o tic an d d izy g o tic twins. Science, 1 5 6 , 5 3 9 . A b stract.
196
A PPEN D IX A
6 1 . Jensen, A. R . ( 1 9 6 7 ) . E stim atio n o f the lim its o f heritability o f traits b y com ­
p ariso n o f m o n o zy g o tic and d iz y g o tic twins. Proceedings of the National Academy of
Science; 5 8 , 1 4 9 —1 5 6 .
6 2 . Jensen, A. R . ( 1 9 6 7 ) . T h e cultu rally disadvantaged: P sych ological a n d educa­
tion al aspects. Educational Research, 1 0, 4—2 0 .
6 3 . Jensen, A. R . ( 1 9 6 7 ) . H o w m uch can we b oost I Q a n d scholastic achievem ent?
Proceedings of the California Advisory Council on Educational Research.
1968
6 4 . Jen sen , A . R . ( 1 9 6 8 ) . S o c ial c la ss, race and gen etics: Im p licatio n s f o r ed u ca­
tio n . American Educational Research Jo u rn al, 5, 1—4 2 R e p rin te d in: G o r d o n , I. J.
( E d .) ,
Readings
in research in developmental psychology.
Glenview,
IL :
S c o tt,
Foresm an , an d C o ., 19 7 1. P p . 5 4 - 6 7 .C la r iz io , H . R , C raig, R . C „ and
M eh ren s, W. H . (E d s .), Contemporary issues in educational psychology. N e w York:
A lly n an d B a co n , 1 9 7 0 .
6 5 . Jensen, A. R . ( 1 9 6 8 ) . P atterns o f m ental ability an d so cio eco n o m ic status.
Science, 160, 4 3 9 . A bstract.
6 6 . Jensen, A. R . ( 1 9 6 8 ) . Patterns o f m ental ability an d so cio eco n o m ic status.
Proceedings of the N ational Academy o f Sciences, 6 0, 1 3 3 0 —1 3 3 7 .
6 7 . Jensen, A. R . ( 1 9 6 8 ) . Social class a n d verbal learn in g. In M . D eu tsc h , I. Katz,
an d A. R . Jen sen (E d s.), Social class, race, and psychological development. N e w York:
H o lt, R in eh art, an d W in ston. P p . 1 1 5 - 1 7 4 . R e p rin te d in: D eC ecco, J. P. (E d .),
The psychology of language, thought, and instruction. N e w Y ork: H olt, R in e h a r t, and
W in sto n , 1 9 6 7 . P p . 103—1 17.
6 8 . Jensen, A. R . ( 1 9 6 8 ) . T h e cu ltu rally disadvan taged an d the heredity-environm en t uncertainty. In J. H e llm u th (E d .), Disadvantaged child. Vol. 2. S e a ttle , W A:
Sp ecial C h ild Pu blication s. P p. 2 9 —7 6 .
6 9 . Jensen, A. R . ( 1 9 6 8 ) . A n oth er lo o k at culture-fair testing. In Western Regional
Conference on Testing Problems Proceedings f o r 1 9 6 8 , M easurem en t fo r E d u c atio n al
Planning. Berkeley, C aliforn ia: E d u c atio n al T e stin g Service, W estern O ffice.
P p . 5 0 —1 0 4 . R ep rin ted in: H e llm u th , J. (E d .), Disadvantaged child. Vol. 3,
Compensatory education: A national debate. N ew Y ork: B ru n n e r/M a z e l, 1 9 7 0 . Pp.
5 3-101.
7 0 . Jensen, A. R . ( 1 9 6 8 ). Influences o f biological, psychological, and so cial depriva­
tio n s u po n learn in g and p erfo rm an ce. In Perspectives on human deprivation.
W ashington, D C : U S . D ep artm e n t o f Health, E ducation, and W elfare. Pp.
1 25-137.
APPEN D IX A
197
7 1 . Jensen, A. R . ( 1 9 6 8 ) . D isc u ssio n o f E rn st Z . R o th k o p h ’s two scien tific
approach es to the m anagem ent o f instructions. In R . M . G agne an d W . J.
G e p h art (E d s .), Learning research and school subjects. Ita sc a , IL : F. E. P eacock . Pp.
1 34—141.
7 2 . Jensen, A. R . ( 1 9 6 8 ) . T h e b io lo g y o f m aladju stm en t. Review o f Studies o f trou­
blesome children, b y D . H . Stott. Contemporary Psychology, 13, 2 0 4 —2 0 6 .
7 3 . Jensen, A. R ., a n d Rohwer, W. D ., Jr. (1 9 6 8 ). M e n ta l retardation, m e n ta l age,
an d learning rate. Journal of Educational Psychology, 5 9 , 4 0 2 - 4 0 3 .
7 4 . D eu tsch , M ., K a tz , I., and J ensen, A . R . (E d s.). ( 1 9 6 8 ) . Social class, race, and psy­
chological development. N e w York: H o lt , Rinehart, an d W in sto n . Pp. v + 4 2 3 .
7 5 . Lee, S . S., an d Jensen , A. R . ( 1 9 6 8 ) . E ffe ct o f aw aren ess on 3-stage m e d ia te d
association . Jo u rn al of Verbal Learning and Verbal Behavior, 1, 1 0 0 5 —100 9 .
1969
7 6 . Jensen, A. R . ( 1 9 6 9 ) . H ow m u ch can we b oost I Q a n d scholastic achievem ent?
H arvard Educational Review, 3 9, I —1 2 3 . R eprin ted in: E nvironm ent, heredity, and
intelligence. H arv ard Educational Review, R eprin t S e rie s N o . 2, 1969. P p . I —1 2 3 .
Congressional Record, M a y 28, 1 9 6 9 , V ol. 1 1 5, N o . 8 8 . P p . H 4 2 7 0 - 4 2 9 8 . Brach t,
G . H ., H o p k in s, K ., and Stanley, J. C . (E d s.), Perspectives in educational and psycho­
logical measurement. N e w York: P ren tice-H all, 1 9 7 2 . P p . 19 1 - 2 13. B arn ette, W.
L ., Jr. (E d .), Readings in psychological tests and measurements. (3 rd ed.). B altim o re:
W illiam s and W ilk in s, 1976. P p . 3 7 0 - 3 8 0 .
7 7 . Jensen, A. R . ( 1 9 6 9 ) . R educin g the heredity-environm ent uncertainty. H arvard
Educational Review, 3 9 , 4 4 9 —4 8 3 . R e p rin te d in: E n v iron m en t, heredity, a n d in tel­
ligence. H arvard Educational Review, R e p rin t Series N o . 2 , 1 9 6 9 . Pp. 2 0 9 —2 4 3 .
7 8 . Jensen, A. R . ( 1 9 6 9 ) . Intelligence, learning ability, a n d socioecon om ic statu s.
Jou rnal of Special Education, 3, 2 3 - 3 5 . R eprin ted in: M ental Health Digest, 1 9 6 9 , Z,
9 -12.
7 9 . Jensen, A. R . ( 1 9 6 9 ) . Understanding readiness: An occasional paper. U rbana, I L : E R I C
C learin ghouse o n E arly C h ild h o o d E ducation , N a t io n a l L ab orato ry o n E arly
C h ild h o o d E d u c atio n . Pp. I —17.
8 0 . Jensen, A. R . ( 1 9 6 9 ) . Jensen’s th e o ry o f intelligence: A reply. Journal of Educational
Psychology, 60, 4 2 7 —4 3 1 .
8 1 . Jensen, A. R . ( 1 9 6 9 ) . T h e p ro m o tio n o f dogm atism . Jou rnal of Social Issues, 2 5 ,
212-2 1 7 , 2 1 9 -2 2 2 .
8 2 . Jensen, A. R . ( 1 9 6 9 ) . C riticism
I0 4 0 -I0 4 I.
o r propagan da? American Psychologist, 2 4 ,
198
APPENDIX A
8 3 . Jensen, A . R . ( 1 9 6 9 ) . A n e m b attle d hypoth esis [interview]. Center Magazine, 2,
7 7-80.
8 4 . Jensen, A. R . ( 1 9 6 9 ) . E d u c a tio n ills: D ia g n o sis a n d cure? Review o f Who can he
educated?, b y M . Schwebel. Contemporary Psychology, 14, 3 6 2 —3 6 4 .
8 5 . Jensen, A . R . ( 1 9 6 9 ) . R eview o f Pygmalion in the classroom, by R . R o se n th a l and
L enore Ja c o b so n . American Scientist, 5 1 , 4 4 A —4 5 A .
8 6 . Jensen, A . R . ( 1 9 6 9 ) . R ac e a n d intelligence: T h e differences are real. Psychology
Today, 3, 4—6. R eprin ted in: S e x to n , Patricia C . ( E d .) , Problems and policy in educa­
tion. N e w Y ork: Allyn and B a co n , 1 9 7 0 .
Jacoby, R ., an d G lauberm an, N . ( E d s .) The Bell Curve debate: History, documents, opinions.
N e w Y ork: R a n d o m H o u se , 1 9 9 5 .
8 7 . Rohw er, W. D „ Jr., and Jen sen , A. R . ( 1 9 6 9 ) . A reply to G la ss . Journal of
Educational Psychology, 6 0, 4 1 7 —4 1 8 .
1970
8 8 . Jensen, A. R . ( 1 9 7 0 ) . A th eory o f prim ary an d secon d ary fam ilial m e n ta l retar­
dation . In N . R . E llis (E d .), International reviews, of research in mental retardation. Vol.
4. N e w Y ork: A cadem ic P ress. P p . 3 3 —105.
8 9 . Jensen, A. R . ( 1 9 7 0 ). H ie rarch ical theories o f m en tal ability. In B. D ockrell
(E d .), On intelligence. T o ro n to : O n tario In stitu te fo r Studies in E d u c a tio n . Pp.
1 1 9 -1 9 0 .
9 0 . Jensen, A. R . ( 1 9 7 0 ). I Q ’s o f identical tw ins reared apart. Behavior Genetics, I,
1 3 3 - 1 4 8 . R ep rin ted in: E ysen ck , H . J. ( E d .) , The measurement o f intelligence.
Lan caster, U K : M edical an d T ech n ical P u b lish in g C o., 1973. P p . 2 7 3 —2 8 8 .
9 1 . Jensen, A . R . ( 1 9 7 0 ). R a c e an d the gen etics o f intelligence: A reply to
Lew on tin. Bulletin of the Atomic Scientists, 2 6, 1 7 - 2 3 . R eprinted in: B aer, D . (E d .),
Heredity and society: Readings in social genetics. N e w Y ork: M acm illan , 1 9 7 3 . Pp.
3 0 0 - 3 1 1 . B lock, N . J., an d D w ork in , G . ( E d s .) , The I Q controversy. N e w York:
Pantheon, 1 9 7 6 . Pp. 9 3 —1 0 6 .
9 2 . Jensen, A. R . ( 1 9 7 0 ). C a n we an d sh o u ld we study race differen ces? In J.
H ellm u th (E d .), Disadvantaged child, Vol. 3, Compensatory education: A national debate.
N e w Y ork: B ru n n e r/M a z e l. P p . 1 2 4 - 1 5 7 . R e p rin te d in: G rig h am , J. C „ and
W eissbach, T . A . (E d s.), Racial attitudes in America: Analysis andfindings o f social psy­
chology. N e w Y ork: H a rp e r an d Row, 1 9 7 1 . P p . 4 0 1 —4 34. Journal o f the American
Anthropological Association, 19 7 1, A n th ro p o lo gical S tu d ie s. N o . 8. W righ tsm an , L.
S., an d Brigh am , J. C . (E d s .), Contemporary issues in social psychology. (2 n d ed.).
M onterey, C A : B r o o k s/C o le , 1 9 7 3 . Pp. 2 1 8 —2 2 7 .
199
A PPEN D IX A
9 3 . Jensen, A . R . ( 1 9 7 0 ) . L e arn in g ability, intelligence, and educability. In V lien
(E d .), Psychologicalfactors in poverty. C h icago: M a rk h a m . Pp. 106—1 3 2 .
9 4 . Jensen, A . R . (1 9 7 0 ) . T h e heritability o f in telligence. Science & Engineering, 33,
4 0 —4 3 . R e p rin te d in: Saturday Evening Post, Su m m er, 1 9 7 2 . R u b in ste in , J„ and
Slife, B. D. (E d s.), Taking Sides: Clashing views on controversial psychological issues.
G u ilford , C T : D u sh k in P u b lish in g G roup, 1 9 8 0 . P p . 2 3 2 —2 3 8 . Z im b a rd o , P.,
and M aslach , C . (E d s.), Psychology f o r our times: Readings. Glenview, I L : Scott,
Foresm an , 1 9 7 3 . Pp. 1 2 9 —1 3 4 .
9 5 . Jensen, A . R . ( 1 9 7 0 ) . S tatem en t o f D r. A rth u r R . Jensen to th e General
S u b co m m ittee on E d u catio n o f the C o m m ittee o n E du cation a n d Labor,
H o u se o f R epresentatives, 9 2 n d C on gress, se co n d session . Hearings on Emergency
School A id Act of 1 9 7 0 . ( H .R .
1 7 8 4 6 ). W ash in gton D C : U .S. G overn m ent
P rin tin g O ffice. P p. 3 3 3 —3 4 2 .
9 6 . Jensen, A . R . ( 1 9 7 0 ) . R eview o f Behavioral genetics: Methods and research, ed ited by
M . M an osevitz, G . L indzey, an d D . D. T h iessen . Social Biology, 17, 1 5 1 —152.
9 7 . Jensen, A. R . ( 1 9 7 0 ) . Parent an d teacher attitudes tow ard in tegration an d bus­
ing. Research Resume, N o . 4 3 , C alifo rn ia A d v iso ry C oun cil on E d u catio n al
R esearch, M a y 1 9 7 0 .
9 8 . Jensen, A . R . ( 1 9 7 0 ) . S e le ctio n o f m inority stu d e n ts in higher e d u c atio n . Toledo
Law Review, S p rin g—Sum m er, N o s . 2 and 3, 3 0 4 —4 5 7 .
9 9 . Jensen, A . R ., an d Rohw er, W. D., Jr. ( 1 9 7 0 ). An experimental analysis o f learning
abilities in culturally disadvantaged children. Final R e p o r t. O ffice o f
E co n o m ic
O p p o rtu n ity , C o n trac t N o . O E O 2 4 0 4 , 1 9 7 0 . P p . I —181.
1971
1 0 0 . Jensen, A . R . ( 1 9 7 1 ) . In dividu al differences in v isu al and au d ito ry memory.
Jou rnal of Educational Psychology, 6 2 , 1 2 3 —131.
1 0 1 . Jensen, A . R . ( 1 9 7 1 ) . C on troversies in intelligence: H ered ity and environm ent.
In D. W. A llen an d E . S e ifm an (E d s .), The teacher’s handbook. Glenview, I L : Scott,
Foresm an an d C o. P p. 6 4 2 —6 5 4 .
1 0 2 . Jensen, A . R . ( 1 9 7 1 ) . T h e role o f verbal m e d iatio n in m ental developm en t.
Journal of Genetic Psychology, 1 1 8 , 3 9 —7 0 .
1 0 3 . Jensen, A . R . (1 9 7 1 ) . H ered ity, environment, an d intelligence. In
L . C.
D eig h to n (E d .), Encyclopedia o f education, Vol. 4 . N e w York: M a c m illa n . Pp.
368-3 8 0 .
1 0 4 . Jensen, A . R . ( 1 9 7 1). T h e race x sex x ability in teraction . In R . C a n c r o (E d .),
Contributions to intelligence. N e w Y ork: G run e an d S tra tto n , 197 1 . P p . 1 0 7 —161.
200
APPEN D IX A
1 0 5 . Jensen, A. R . ( 1 9 7 1 ) . A note o n why genetic c o rre latio n s are n o t squared.
Psychological Bulletin, 75, 2 2 3 —2 2 4 .
1 0 6 . Jensen, A. R . ( 1 9 7 1 ) . H eb b ’s c o n fu sio n about heritability. American Psychologist,
26, 3 9 4 -3 9 5 .
1 0 7 . Jensen, A. R . ( 1 9 7 1). Twin d ifferen ces and race d ifferen ces in IQ : A reply to
Burgess and Ja h o d a . Bulletin of the British Psychological Society, 2 4, 1 9 5 —1 9 8 .
1 0 8 . Jensen, A. R . ( 1 9 7 1 ) . Erblicher I .Q . o d e r P äd ago g isch er O p tim ism u s v o r einem
anderen G erich t. Neue Sammlung, 11, 7 1 —76.
1 0 9 . Jensen, A. R . ( 1 9 7 1 ) . D o schools ch eat m inority children? Educational Research, 14,
3 -28.
1 1 0 . Jensen, A. R . ( 1 9 7 1 ) . T h e ph ylogeny and ontogeny o f intelligence. Perspectives in
Biology and Medicine, 15, 3 7 —4 3 .
1 1 1 . Jensen, A. R . ( 1 9 7 1 ) . H ered ity a n d environm ent: A controversy over I Q and
sch olastic ach ievem ent. In H . C . L in d gren an d F re d rica L in d g re n (E d s .),
Current readings in educational psychology. (2 n d
e d .). N e w York: W iley . Pp.
3 2 3-327.
1972
1 1 2 . Jensen, A. R . ( 1 9 7 2 ) . Genetics and education. L o n d o n : M ethuen (N e w York:
H arp e r and R o w ). Pp. vii + 3 7 9 .
1 1 3 . Jensen, A. R . ( 1 9 7 2 ) . A tw o-factor theory o f fa m ilia l m ental retardation . In J.
deGrouchy, F. J. G . Ebling, a n d I. W. H e n d e rso n (E d s.), H um an genetics.
Proceedings o f th e 4th In te rn atio n al C on gress o f H u m an G en etics, Paris,
Septem ber 1 9 7 1 . Am sterdam : E x c e rp ta M edica, 1 9 7 2 . Pp. 2 6 3 —2 7 1 .
1 1 4 . Jensen, A. R . ( 1 9 7 2 ) . Review o f A n alysis o f L e a rn in g Potential. In O . K . Büros
(E d .), Seventh mental measurements yearbook. H ig h lan d Park, N J: G ry p h o n Press.
V ol. I. Pp. 6 2 2 - 6 2 5 .
1 1 5 . Jensen, A. R . ( 1 9 7 2 ) . T h e case fo r I Q tests: R ep ly to M cC lellan d. The Humanist,
3 2 , 14.
1 1 6 . Jensen, A. R . ( 1 9 7 2 ) . T h e causes o f twin d ifferen ces in IQ : A reply to Gage.
Phi Delta Kappan, 5 3 , 4 2 0 —4 2 1 .
1 1 7 . Jensen, A. R . ( 1 9 7 2 ) . Genetics a n d education: A se c o n d look. N ew Scientist, 5 6,
9 6 -98 .
1 1 8 . Jensen, A. R . ( 1 9 7 2 ) . Sch olastic achievem ent an d intelligence (S tate m e n t to the
U . S. Sen ate S e le c t C om m ittee on E qual E d u c a tio n a l O p p o rtu n ity ). In
Environment, Intelligence, and Scholastic Achievement (A c o m p ilatio n o f testim o n y to
the Select C o m m itte e on E q u a l E ducation al O p p o rtu n ity , U n ite d States
Senate, 9 2 n d C o n g re ss, 2 n d S e ssio n , June 1 9 7 2 ) . W ashington, D C : U .S.
APPEN D IX A
201
G overnm ent P rin tin g O ffice. P p . 5 5 - 6 8 . R e p rin te d in: Saturday Evening Post,
1972, 2 4 4 (2 ), 1 5 0 -15 2 .
1 1 9 . Jensen, A. R . ( 1 9 7 2 ) . In terpretatio n o f heritability. American Psychologist, 27,
97 3-975.
1 2 0 . Jensen, A. R . ( 1 9 7 2 ) . I.Q . and R a c e : E th ical issues. The Humanist, 3 2 , 5 —6.
1 2 1 . Jensen, A. R . ( 1 9 7 2 ) . H e ritab ility a n d teachability. In J. E . Bruno (E d .), Emerging
issues in education. Lexington, M A : D . C . H eath. P p. 5 7 —8 8 .
12 2 . Jensen, A. R . ( 1 9 7 2 ) . C om m en t o n D e Fries’s p a p e r. In Lee E h rm an , G . S.
O m en n , and E . C asp ari (E d s.), Genetics, environment, and behavior. N e w Y ork:
A cadem ic Press, 1 9 7 2 . Pp. 2 3 —2 5 .
1 2 3 . Jensen, A. R . ( 1 9 7 2 ) . D isc u ssio n o f Tobach ’s pap er. In Lee E h rm an , G . S.
O m enn , and E . C asp ari (E d s.), Genetics, environment, and behavior. N e w Y ork:
A cadem ic Press, 1 9 7 2 . Pp. 2 4 0 —2 4 6 .
1 2 4 . Jensen, A. R . ( 1 9 7 2 ) . Educabilité, tran sm ission h éréditaire et differen ces entre
pop u lation s. (E d u cab ility , h eritability, and p o p u la tio n differences.) Revue de
Psychologie Appliqué, 2 2 , 2 1 —34.
1 2 5 . Jensen, A. R . ( 1 9 7 2 ) . Review o f Race, culture and intelligence, edited by K.
R ich ardson , D . S p e a rs, and M . R ic h a rd s. New Society, 4 9 1 , 4 0 8 —4 1 0 .
1 2 6 . Jen sen , A. R . ( 1 9 7 2 ) . S ir Cyril B u r t [O bituary], Psychometrika, 3 1 , 1 1 5 —1 1 7 .
1 2 7 . Jen sen , A. R . ( 1 9 7 2 ) . Jensen on H ir sc h on "jen sen ism .” Educational Researcher, I,
1 5 -16 .
1 2 8 . Jen sen, A. R . ( 1 9 7 2 ) . A ssessm en t o f racial d esegreg atio n in the Berkeley
Sc h o o ls. In D . A d e lso n (E d .), M an as the measure: The crossroads. (C o m m u n ity
P sych ology Series, N o . I. A m erican P sych ological A sso ciatio n , Div. 2 7 .) N e w
Y ork : Behavioral P u blications, In c. P p . 1 1 6 - 1 3 3 .
1 2 9 . Jen sen , A. R . ( 1 9 7 2 ) . E ducability, heritability, a n d po p u latio n differen ces.
Proceedings of the 17th International Congress of Applied Psychology. Brussels, B elgium :
E d ite st.
1 3 0 . Jen sen , A. R . ( 1 9 7 2 ) . L e tter-to -th e -E d ito r on gen etic I Q differences am o n g
so c ia l classes. Perspectives in Biology and Medicine, 116, 1 5 4 —1 56.
1 3 1 . Jensen, A. R . ( 1 9 7 2 ) . Review o f
W LW Culture F a ir Inventory. In O . K . B u ros
(E d .), Seventh mental measurements yearbook. H igh lan d P ark, N J: G ry p h o n P ress,
V ol. I . Pp. 7 2 0 - 7 2 1 .
1 3 2 . Jen sen , A. R . ( 1 9 7 2 ) . T h e I Q controversy: A reply to Layzer. Cognition, 4,
427 -4 5 2 .
1 3 3 . Jen sen , A. R . ( 1 9 7 2 ) . E m pirical b a s is o f the perio dic tab le o f hum an cultures.
In E . H askell (E d .), F u ll circle: The moralforce of unified science. N e w Y ork: G o r d o n
an d Breach, 1 9 7 2 . P p. 1 5 6 - 1 6 4 .
APPENDIX A
202
1973
1 34. Jensen, A . R . (1 9 7 3 ) . A case fo r dysgenics. The Journal: Forum f o r Contemporary
History, 2 (4 ) , 1 - 6 .
135. Jensen, A . R . ( 1 9 7 3 ) . S o m e facts ab ou t the IQ . The Journal: Forum f o r Contemporary
History, 2 (7 ) , 68.
1 3 6 . Jensen, A . R . (1 9 7 3 ) . E x p a n d in g the thesis: T h e I Q controversy. R eview o f I Q
in the meritocracy, b y R . J. H e rrn ste in . Book World, Chicago Tribune, Ju n e 2 4 , 1973.
1 3 7 . Jensen, A . R . ( 1 9 7 3 ) . O n “ Jen sen ism ” : A reply to critics. In B. Jo h n so n (E d .),
Education yearbook, 1 9 7 3 - 7 4 . N e w York: M a c m illa n E d u catio n al C o rp o ratio n .
Pp. 276-298.
1 3 8 . Jensen, A . R . ( 1 9 7 3 ) . R ace, intelligence an d gen etics: T h e differen ces are real.
Psychology Today, 7, 8 0 - 8 6 . R e p rin te d in: D u rla n d , W. R ., and B ru en in g, W. H .
(E d s .). Ethical issues. P alo A lto, C A : M ayfield, 1 9 7 5 . P p. 4 0 3 —4 1 4 . W h iteh ead,
Jo an M . (E d .). Personality and learning I. L o n d o n : H o d d e r and S to u g h to n , 1975.
P p. 3 4 5 —3 5 1 . Schell, R . E . (E d .). Readings in developmental psychology today. (2n d
ed.). N e w Y ork: R a n d o m H o u se , 1 9 7 7 . P p . 2 3 0 —2 3 4 . Brigh am , J. C., and
W righ tsm an , L . S . (E d s .). Contemporary issues in social psychology. (3 r d ed.).
M onterey, C A : B r o o k s/C o le , 1 9 7 7 .
1 3 9 . Jensen, A . R . (1 9 7 3 ) . C ritics o f the IQ . R eview o f The fallacy o f I Q , edited by
C . Sen n a. Georgia Review, 2 7 , 4 3 9 - 4 4 5 .
1 4 0 . Jensen, A . R . ( 1 9 7 3 ) . P erson ality and sch o lastic achievement in three ethnic
g ro u p s. British Journal of Educational Psychology, 4 3 , 1 1 5 —125.
1 4 1 . Jensen, A. R . ( 1 9 7 3 ) . L e t’s un derstan d S k o d a k an d Skeels, finally. Educational
Psychologist, 10, 3 0 —3 5 .
1 4 2 . Jensen, A . R . ( 1 9 7 3 ) . S k in n e r an d hum an differen ces. In H . W h e e le r (E d .),
Beyond the punitive society. S a n Fran cisco: W. H . Freem an . Pp. 1 1 7 - 1 9 8 .
14 3 . Jensen, A . R . ( 1 9 7 3 ) . Educability and group differences. L o n d o n : M e th u e n (N ew
Y ork: H a rp e r and R o w ). P p . x iii + 4 0 7 .
1 4 4 . Jensen, A . R . ( 1 9 7 3 ) . Educational differences. L o n d o n : M ethuen. (N e w York:
B arn es an d N o b le ). P p. x iii + 4 6 2 .
145. Jensen, A. R . (1 9 7 3 ). Bildungsfähigkeit, Erblichkeit u n d Bevölkerungsunterschiede.
Neue Anthropologie, l, 37-4-3.
1 4 6 . Jensen, A. R . ( 1 9 7 3 ) . Level I and Level II ab ilities in three eth n ic groups.
American Educational Research Journal, 4, 2 6 3 —2 7 6.
1 4 7 . Jensen, A . R . ( 1 9 7 3 ) . W ie sehr können w ir In telligen z Q u otien t u n d schulische
L e istu n g steigern? In H . Skow ronek (E d .), Umwelt Lind Begabung. S tu ttgart, W.
G erm an y : K le tt /C o tt a . (P ap erb ack edition p u b lish e d by U llste in Taschenbuch
V erlag, 1 9 8 2 .)
203
APP E N D IX A
1 4 8 . Jensen, A. R ., an d Frederiksen, J. ( 1 9 7 3 ) . Free recall o f categorized an d u n cat­
egorized lists: A test o f the Jen sen h ypoth esis. Jou rn al of Educational Psychology, 65,
3 04 -3 1 2 .
1974
1 4 9 . Jen sen , A. R .
(1 9 7 4 ). W h at
is
th e qu estio n ? W h a t is the
eviden ce?
[A utobiograph y.] In T. S. K raw iec (E d .), The psychologists. Vol. 2. N e w York:
O x fo rd U n iversity Press. Pp. 2 0 3 —2 4 4 .
1 5 0 . Jensen, A. R . ( 1 9 7 4 ) . Kinship co rre latio n s rep orted by S ir Cyril B urt. Behavior
Genetics, 4 ( I ) , 1—2 8 .
1 5 1 . Jensen, A. R . ( 1 9 7 4 ) . Review o f Abilities: Their structure, growth, and action, b y R . B.
C attell. American Jou rn al of Psychology, 8 1 , 2 9 0 —2 9 6 .
1 5 2 . Jensen, A. R . ( 1 9 7 4 ) . Review o f Genetic diversity and human equality, b y T h .
D ob zh an sky . Perspectives in Biology and Medicine, 1 1, 4 3 0 —4 3 4 .
1 5 3 . Jensen, A. R . ( 1 9 7 4 ) . H ow b ia se d are cultu re-loaded tests? Genetic Psychology
Monographs, 9 0 , 1 8 5 —2 4 4 .
1 5 4 . Jensen, A. R . ( 1 9 7 4 ) . E ffects o f race o f examiner o n the m ental test sc o re s o f
white and b lack pu p ils. Journal o f Educational Measurement, 11, I —14.
15.5. Jensen, A. R . ( 1 9 7 4 ) . Ethnicity an d scholastic achievem ent. Psychological Reports,
34, 659 -66 8 .
1 5 6 . Jensen, A. R . ( 1 9 7 4 ) . Cum ulative deficit: A testable hypothesis? Developmental
Psychology, 10, 9 9 6 —1 0 1 9 .
1 5 7 . Jen sen , A. R . ( 1 9 7 4 ) . In te ractio n o f Level I an d L e v e l I I ab ilities w ith race
a n d so c io e c o n o m ic status. Jo u r n a l o f Educational Psychology, 6 6 , 9 9 —1 1 1 .
R e p rin te d in: W ittro c k , M . C . ( E d .) , Learning and instruction. Berkeley, C A :
M cC u tc h a n , 1 9 7 7 . P p. 2 7 0 —2 9 0 .
1 5 8 . Jensen, A. R . ( 1 9 7 4 ) . E quality fo r m in orities. In H . J. W alberg (E d .), Evaluating
educational peformance. Berkeley, C A : M cC u tch an . P p . 1 7 5 —2 2 2 .
1 5 9 . Jensen, A. R . ( 1 9 7 4 ) . T h e stran ge case o f Dr. Jen sen an d M r. H yde? American
Psychologist, 2 9 , 4 6 7 —4 6 8 .
1 6 0 . Je n se n , A . R . ( 1 9 7 4 ) . E d u c a b ility an d g ro u p
d ifferen ces. N ature, 2 5 0 ,
7 13-714.
1 6 1 . Jensen, A. R . ( 1 9 7 4 ) . R ace a n d intelligence: T h e case for gen etics. Times
Educational Supplement, L on don , S e p te m b e r 2 0 , 1 9 7 4 , N o . 3 0 9 5 , 2 0 —2 1 .
1975
1 6 2 . Jensen, A. R . ( 1 9 7 5 ) . T h e price o f inequality. O xford Review of Education, I ( I ) ,
1 3 -25 .
APPENDIX A
204
16 3 . Jensen, A . R . ( 1 9 7 5 ) . L es fon d em en ts scien tifiqu es des inégalités eth n iques. Le
Monde Diplomatique, June 1 9 7 5 , N o . 2 5 5 , 19.
1 6 4 . Jensen, A. R . ( 1 9 7 5 ) . A th eoretical note on sex lin kage and race differen ces in
sp atial ability. Behavior Genetics, 5, 1 5 1 —1 64.
1 65. Jensen, A . R . ( 1 9 7 5 ) . T h e m ean in g o f h eritability in the behavioral sciences.
Educational Psychologist, 11, 1 7 1 —1 8 3 .
1 6 6 . Jensen, A . R . ( 1 9 7 5 ) . P an o ram a o f m odern beh avioral genetics. Review o f
Introduction to behavioral genetics, by G . E . M c C le a m a n d J. C . D eF ries. Contemporary
Psychology, 2 0 , 9 2 6 —9 2 8 .
1 6 7 . Jensen, A. R . ( 1 9 7 5 ) . R ac e an d m ental ability. In J. F. E blin g (E d .), Racial vari­
ation in man. L o n d o n : In stitu te o f B io lo g y /B la ck w ell. Pp. 7 1 - 1 0 8 .
1 6 8 . Jensen, A . R . ( 1 9 7 5 ) . E s g ib t U n tersch iede zw isch en Schw arzen an d W eissen?
Psychologie Heute, Jan. 1 9 7 5 , 6 3 —7 5 .
1 6 9 . Jensen, A . R . (1 9 7 5 ) . Interview : R a sse un d B egab u n g. Nation Europa, Septem ber
1975, 1 9 -2 8 .
1 7 0 . Jensen, A . R ., an d Figu eroa, R . A . ( 1 9 7 5 ). F o rw ard and backw ard d igit span
interaction w ith race and IQ : Prediction s fr o m Jensen’s theory. Journal of
Educational Psychology, 6 7 , 8 8 2 —8 9 3 .
1976
1 71. Jensen, A . R . (1 9 7 6 ) . R ac e differences, strate gy training, and im p ro p e r infer­
ence. Jou rnal of Educational Psychology, 68, 1 3 0 —1 3 1 .
1 7 2 . Jensen, A . R . ( 1 9 7 6 ) . E q u ality an d diversity in education . In A sh lin e, N . F.,
Pezullo, T . R .., an d N o r ris , C . I. (E d s.), Education, inequality, and national policy.
L exin gton, M A : L exin gton B o o k s, 1 9 7 6 . P p . 1 2 5 —136.
1 7 3 . Jensen, A . R . ( 1 9 7 6 ) . A d d e n d u m to hum an d iversity discussion . In B. D. Davis
and P atricia Flah erty (E d s .), Hum an diversity: Its causes and social significance.
C am b rid ge, M A : Ballinger, 1 9 7 6 . Pp. 2 2 3 —2 2 8 .
1 7 4 . Jensen, A . R . ( 1 9 7 6 ) . T w in s’ I Q ’s. A reply to Sc h w a rtz and Sch w artz. Behavior
Genetics, 6, 3 6 9 —3 7 1 .
1 7 5 . Jensen, A . R . ( 1 9 7 6 ) . E in e Z w eifactoren th eorie des fam iliären Schw achsinns.
Neue Anthropologie, 4, 5 3 6 0 .
17 6 . Jensen, A. R . ( 1 9 7 6 ) . T e st b ias and c o n stru ct validity. Phi Delta Kappan, 5 8 ,
3 4 -346.
1 7 7 . Jensen, A. R . ( 1 9 7 6 ) . H e ritab ility o f I Q [L e tte r-to -th e -E d ito r]. Science, 194,
6 -14.
APPENDIX A
205
1 7 8 . Jensen, A . R . ( 1 9 7 6 ) . T h e problem o f gen otype-en viron m en t correlation in the
estim ation o f h eritability from m o n o zy g o tic and d izy g o tic tw ins. Acta Geneticae
Medicae et Gemellologiae, 2 5 , 8 6 —99.
1977
1 7 9 . Jensen, A . R . ( 1 9 7 7 ) . A n exam ination o f culture b ia s in the W on d erlic
P erson nel Test. Intelligence, I, 5 1 6 4 .
1 8 0 . Jensen, A . R . ( 1 9 7 7 ) . Cum ulative d e ficit in I Q o f b lack s in the rural S o u th .
Developmental Psychology, 13, 18 4 1 —18 9 1 .
R ep rin ted in: W illerm an, L ., an d Turner, R . G . (E d s.), Readings about individual and group
differences. San Fran cisco : W . H . Freem an, 1 9 7 9 . Pp. 8 3 —9 1 .
1 8 1 . Jensen, A . R . ( 1 9 7 7 ) . R a c e and m ental ability. In A. H . H a ls e y (E d .), Heredity
and environment. L o n d o n : M ethuen. P p. 2 1 5 —2 6 2 .
18 2 . Jensen, A . R . ( 1 9 7 7 ) . A n un foun ded con clusio n in M . W . S m ith ’s analysis o f
culture b ias in the S tan ford -B in et intelligence scale. Genetic Psychology Monographs,
1 3 0 , 1 1 3 —1 15.
1 8 3 . Jensen, A . R . ( 1 9 7 7 ) . D id S ir C yril B u rt fake his research o n heritability o f
intelligence? Phi D elta Kappan, 5 8 , 4 7 1 —4 9 2 . R e p rin te d in: Education Digest,
M arch 1 9 7 7 , 4 2 , 4 3 - 4 5 .
1 8 4 . Jensen, A . R . ( 1 9 7 7 ) . D ie falschen A n scullidigun gen gegen S ir Cyril Burt. Neue
Anthropologic, 5, 1 5 —16.
1978
1 8 5 . Jensen, A . R . ( 1 9 7 8 ) . G e n e tic and behavioral effects o f n o n ra n d o m m ating. In
R . T. O sb orn e, C . E . N o b le , and N . W eyl (E d s.), H um an variation. N ew Y ork :
A cad em ic Press. P p . 5 1 —1 05.
18 6 . Jensen, A . R . ( 1 9 7 8 ) . S e x linkage and race differences in sp a tia l ability: A reply.
Behavioral Genetics, 8, 2 1 3 —2 1 7 .
1 8 7 . Jensen, A . R . ( 1 9 7 8 ) . S ir Cyril B u rt in perspective. American Psychologist, 3 3 ,
499 -5 0 3 .
1 8 8 . Jensen, A . R . ( 1 9 7 8 ) . T h e current sta tu s o f the I Q controversy. Australian
Psychologist, 13, 7—2 8 .
18 9 . Jensen, A . R . ( 1 9 7 8 ) . T h e nature o f intelligence and its re la tio n to learning. In
S . M u rray -S m ith ( E d .) , Melbourne studies in education. M e lb o u rn e U n iversity
Press. P p. 1 0 7 —1 3 3 . R e p rin te d in: Jou rn al of Research and Development in Education,
12, 7 9 - 9 5 .
19 0 . Jensen, A. R . ( 1 9 7 8 ) . R a c ism refuted [C o rresp o n d en ce], Nature, 2 7 4 , 7 3 8 .
206
APPENDIX
1 9 1 . Jensen, A . R . ( 1 9 7 8 ) . Z u m
A
Stan d d e s S treits um die Intelligenz. Neue
Anthropologie, 6, 2 9 —4 0 .
1 9 2 . Jensen, A . R . ( 1 9 7 8 ). I Q controversy. Baltimore Sun, Nov. 2 4 , 1 9 7 8 , A I2 .
19 3 . Jensen, A . R . ( 1 9 7 8 ). C ita tio n C lassics (H o w much can we b o o s t I Q an d
sch o lastic achievement?). Current Contents, N o . 4 1 (O cto b e r 9 ) , 16.
1979
19 4 . Jensen, A . R . ( 1 9 7 9 ) . g: O u tm o d e d th eory o r un conquered frontier? Creative
Science and Technology, 2 , 1 6 —2 9 .
19 5 . Jensen, A . R . (1 9 7 9 ). R eview o f Inheritance o f creative intelligence, b y J. L . K arlsson .
Jo u rn al of Nervous and M ental Diseases, 167, 7 1 1—7 1 3 .
1 9 6 . Jensen, A . R ., and M a risi, D . Q . ( 1 9 7 9 ). A n o te on the h eritab ility o f m em ory
span. Behavior Genetics, 9, 3 7 9 —3 8 7 .
1 9 7 . Jensen, A . R ., and M u n ro , E . ( 1 9 7 9 ). R e a c tio n time, m ovem ent tim e, and intel­
ligence. Intelligence, 3, 1 2 1 —1 2 6 .
1 9 8 . Jensen, A . R ., and O sb o r n e , R . T. ( 1 9 7 9 ) . Forw ard and b ack w ard digit span
in teraction with race an d I Q : A lon gitu d in al developm ental co m p ariso n . Indian
Jou rnal of Psychology, 5 4 , 7 5 —8 7 .
1980
1 9 9 . Jensen, A . R . ( 1 9 8 0 ). B ias in mental testing. N e w York: T h e F ree P ress (L o n d o n :
M e th u en ). Pp. xiii + 7 8 6 .
2 0 0 . Jensen, A. R . ( 1 9 8 0 ). U s e s o f sibling d a ta in educational a n d psychological
research. American Educational Research Journal, I 7, 1 5 3 —170.
2 0 1 . Jensen, A. R . ( 1 9 8 0 ). C h ro n o m etric analysis o f intelligence. Jo u rn al of Social and
Biological Structures, 3, 1 0 3 —1 2 2 .
2 0 2 . Jensen, A . R . ( 1 9 8 0 ). P ré c is o f Bias in M ental Testing. Behavioral and Brain Sciences, 3,
3 2 5 -3 3 3 .
2 0 3 . Jensen, A. R . (1 9 8 0 ). C o rre c tin g the b ias ag ain st mental testin g : A prepon der­
ance o f peer agreem ent. Behavioral and Brain Sciences, 3, 3 5 9 —3 7 1 .
2 0 4 . Jensen, A. R . ( 1 9 8 0 ). A critical took at te st bias: Fallacies a n d m anifestation s.
N ew Horizons, 2 1, 4 4 —6 4 .
2 0 5 . Jensen, A. R ., and In ouye, A . R . ( 1 9 8 0 ). L evel I and Level II ab ilities in A sian,
W h ite , an d Black children. Intelligence, 4, 4 1 —4 9 .
1981
2 0 6 . Jensen, A . R . ( 1 9 8 1 ). Straight talk about mental tests. N ew Y ork: F re e Press. Pp. xiv
+ 269.
APPENDIX
207
A
2 0 7 . Jensen, A. R . ( 1 9 8 1). R aisin g the I Q :T h e R am ey an d H a sk in s Study. Intelligence,
5, 2 9 - 4 0 .
2 0 8 . Jensen, A. R . ( 1 9 8 1). O b stacles, prob lem s, an d p itfa lls in differential p sy ch o l­
ogy. In S . Scarr, Race, social class, and individual differences in I Q H illsd ale, N J :
Erlbaum . P p. 4 8 3 —5 1 4 .
2 0 9 . Jensen, A. R . ( 1 9 8 1). R eaction tim e an d intelligence. In M . Friedm an, J.
P. D a s,
an d N . O ’C o n n o r (E d s.), Intelligence and learning. N e w Y ork: Plenum . Pp. 3 9 —5 0 .
2 1 0 . Jensen, A. R . ( 1 9 8 1). Im p re ssio n s o f India.
Update (G rad u a te S c h o o l o f
E ducation , U n iversity o f C alifo rn ia , Berkeley), W inter.
2 1 1 . Jensen, A. R . ( 1 9 8 1). C itation C lassic (T h e S tro o p color-w ord test: A review).
Current Contents, 13, 2 0 .
2 1 2 . Jensen, A. R . ( 1 9 8 1 ) . An interview w ith A rth ur Jensen. Communique (N a tio n a l
A ssociation o f S c h o o l P sy ch o lo gists), 10, 3—5.
2 1 3 . Jensen, A. R . ( 1 9 8 1 ) . T ab oo, constraint, an d re sp o n sib ility in edu cation al
research. N ew Horizons, 2 2 , 1 1—2 0 .
2 1 4 . Jensen, A. R . ( 1 9 8 1). A nontechnical guide to the I Q controversy. New Horizons,
22, 1 -2 6 .
2 1 5 . Jensen, A. R ., Sch afer, E. W. P., an d Crinella, F. ( 1 9 8 1 ). R e actio n time, evoked
brain poten tials, an d psychom etric g in the severely retarded. Intelligence, 5,
179-1 9 7 .
1982
2 1 6 . Jensen, A. R . ( 1 9 8 2 ) . Intelligence. In S . B. Parker (E d .), Encyclopedia of science and
technology. (5 th ed.). N e w York: M c G raw -H ill.
2 1 7 . Jensen, A. R . ( 1 9 8 2 ) . Bias in m en tal testing: A fin al w ord. Behavioral and Brain
Sciences, 5, 3 3 9 —3 4 0 .
2 1 8 . Jensen, A. R . ( 1 9 8 2 ) . T h e chron om etry o f intelligence. In R . J. Stern b erg (E d .),
Advances in the psychology of human intelligence, Vol. I. H illsd ale , N J: E rlb aum .
Pp.
2 5 5-310.
2 1 9 . Jensen, A. R . ( 1 9 8 2 ) . R eaction tim e and psychom etric g. In H . J. E ysenck (E d .),
A modelf o r intelligence. N e w Y ork: Sprin ger. Pp. 9 3 —1 3 2 .
2 2 0 . Jensen, A. R . ( 1 9 8 2 ) . C h an gin g co n cep tio n s o f intelligence. Education and Training
o f the Mentally Retarded, 1 7, 3—5.
2 2 1 . Jensen, A. R . ( 1 9 8 2 ) . T h e deb un kin g o f scientific fo ssils an d straw perso n s.
Essay-review o f The mismeasure of man, by S . J. G o u ld . Contemporary Education
Review, I, 1 2 1 —1 3 5 .
2 2 2 . Jensen, A. R . ( 1 9 8 2 ) . Level I /L e v e l I I : Facto rs o r categories? Jou rnal of
Educational Psychology, 74, 8 6 8 —8 7 3 .
208
APPENDIX
A
2 2 3 . Jensen, A . R . (1 9 8 2 ). T h e race concept: P h y sical variation an d co rre lated so cial­
ly sign ifican t behavioral variation. Current Anthropology, 2 3 , 6 4 9 —6 5 0 .
2 2 4 . Jensen, A . R ., and R e y n o ld s, C . R . ( 1 9 8 2 ) . R ac e , social class, an d ab ility p at­
tern s on the W IS C -R . Personality and Individual Differences, 3, 4 2 3 - 4 3 8 .
1983
2 2 5 . Jensen, A , R . ( 1 9 8 3 ). S ir C y ril Burt: A p erso n al recollection . Association of
Educational Psychologists Journal, 6, 13—2 0 .
2 2 6 . Jensen, A . R . ( 1 9 8 3 ). E ffe c ts o f inbreeding o n m ental-ability fac to rs. Personality
and Individual Differences, 4 , 7 1 —8 7 .
2 ,2 1 . Jensen, A . R . (1 9 8 3 ). T h e n on m an ipu lab le an d effectively m an ip u lab le variables
in ed u cation . Education and Society, 5 1 —6 2 . R e p rin te d in: New Horizons, 1 9 8 3 , 24,
31 -5 0 .
2 2 8 . Jensen, A . R . ( 1 9 8 3 ). R eview o f The testing of Negro intelligence (V o l. II), edited by
R . T. O sb o rn e and F. C . J. M cG u rk . Personality and Individual Differences, 4,
234-235.
2 2 9 . Jensen, A . R . ( 1 9 8 3 ). R eview o f The inheritance of personality and ability, by R . B.
C attell. Personality and Individual Differences, 4, 3 6 5 —3 6 8 .
2 3 0 . Jensen, A . R . ( 1 9 8 3 ). T h e d efin itio n o f intelligence and fac to r score indeter­
m inacy. Behavioral and Brain Sciences, 6, 3 1 3 —3 1 5 .
2 3 1 . Jensen, A . R . (1 9 8 3 ). A g ain , how m uch can we b o o st IQ ? R eview o f H ow and
how much can intelligence be increasedf e d ite d by D. K. D ette rm an an d R . J.
Stern b erg. Contemporary Psychology, 2 8 , 7 5 6 —7 5 8 .
2 3 2 . Jensen, A . R . ( 1 9 8 3 ). C ritica l flicker frequen cy and intelligence. Intelligence, 1,
2 1 7 -2 2 5 .
2 3 3 . Jensen, A . R . ( 1 9 8 3 ) . T a b o o , con straint, an d respo n sib ility in education al
research. Journal of Social, Political and Economic Studies, 8, 3 0 1 —3 1 1 .
2 3 4 . Jensen, A . R . (1 9 8 3 ). B e y o n d G ro th ’s so c io lo g ic a l criticism o f psychom etrics.
Wisconsin Sociologist, 2 0 , 1 0 2 —1 0 5 .
2 3 5 . Jensen, A . R ., and R e y n o ld s, C . R . ( 1 9 8 3 ) . Sex differences o n the W I S C - R .
Personality and Individual Differences, 4, 2 2 3 —2 2 6 .
2 3 6 . R ey n o ld s, C . R ., and Jen sen , A . R . ( 1 9 8 3 ) . W I S C - R subscale p a tte rn s o f abil­
ities o f blacks and w hites m atch ed o n fu ll scale IQ . Jou rn al of Educational
Psychology, 73, 2 0 7 —2 1 4 .
2 3 7 . Sen, A ., Jensen, A. R ., S e n , A . K., an d A rora, I. C orrelation betw een reaction
tim e an d intelligence in psychom etrically sim ilar grou ps in A m erica an d India.
Applied Research in Mental Retardation, 4, 1 3 9 —1 5 2 .
APP ENDIX A
209
1984
2 3 8 . Jensen, A. R . ( 1 9 8 4 ) . Francis G a lto n ( 1 8 2 2 - 1 9 1 1 ). In R . J. C o r sim (E d .),
Encyclopedia of psychology (V ol. 2 , p. 4 3 ) . N ew Y ork: W iley.
2 3 9 . Jensen, A. R . ( 1 9 8 4 ) . K arl P earso n (1 8 5 7 —1 9 3 6 ) . In R . J. C o rsin i (E d .),
Encyclopedia of psychology (V ol. 2 , p p . 4 9 0 - 4 9 1 ) . N e w Y ork: Wiley.
2 4 0 . Jensen, A. R . ( 1 9 8 4 ) . Charles E d w a rd Spearm an ( 1 8 6 3 —1 9 4 5 ). In R . J. C orsin i
(E d .), Encyclopedia of psychology (V o l. 3, pp. 3 5 3 —3 5 4 ) . N e w York: W iley.
2 4 1 . Jensen, A. R . ( 1 9 8 4 ) . L o u is L e o n T h u rsto n e ( 1 8 8 7 —1 9 5 5 ). In R . J. C orsin i
(E d .), Encyclopedia of psychology (V o l. 3, pp. 4 2 6 —4 2 7 ) . N e w York: W iley.
2 4 2 . Jensen, A. R . ( 1 9 8 4 ) . Law o f filial regression. In R . J. C orsin i (E d .), Encyclopedia
of psychology (V o l. 2, pp. 2 8 0 —2 8 1 ) . N e w York: W iley.
2 4 3 . Jensen, A. R . ( 1 9 8 4 ) . C ultural b ias in tests. In R . J. C o rsin i (E d .), Encyclopedia of
psychology (V o l. I , pp . 3 3 1 —3 3 2 ) . N e w York: W iley.
2 4 4 . Jensen, A . R . ( 1 9 8 4 ) . In b reedin g in hum an fac to rs. In R . J. C o rsin i (E d .),
Encyclopedia of psychology (V ol. 2 , p p . 1 9 1 —1 9 2 ). N e w Y ork: Wiley.
2 4 5 . Jensen, A. R . ( 1 9 8 4 ) . G eneral intelligence facto r. In R . J. C o rsin i (E d .),
Encyclopedia of psychology (V ol. 2 , p. 4 8 ) . N ew Y ork: W iley.
2 4 6 . Jensen, A. R . ( 1 9 8 4 ) . H eritability. In R . J. C o rsin i (E d .), Encyclopedia of psycholo­
gy (V ol. 2 , p. 1 0 8 ). N ew Y ork: W iley.
2 4 7 . Jensen, A. R . ( 1 9 8 4 ) . Test bias: C o n c e p ts and c riticism s. In C. R . R e y n o ld s and
R . T. Brow n (E d s .), Perspectives on bias in mental testing. N e w York: P len u m . Pp.
507-586.
2 4 8 . Jensen, A. R . ( 1 9 8 4 ) . P olitical id eologies an d e d u catio n al research. Phi Delta
Kappan, 6 5 , 4 6 0 —4 6 2 .
2 4 9 . Jensen, A. R . ( 1 9 8 4 ) . T h e lim ite d plasticity o f hum an intelligence. New
Horizons, 2 5 , 1 8 —2 2 .
2 5 0 . Jensen, A. R . ( 1 9 8 4 ) . M en tal sp e e d and levels o f analysis. Behavioral and Brain
Sciences, 7, 2 9 5 —2 9 6 .
2 5 1 . Jensen, A. R . ( 1 9 8 4 ) . Test validity: g versus the specificity doctrine. Jou rn al of
Social and Biological Structures, 7, 9 3 —1 18.
2 5 2 . Jensen, A. R . ( 1 9 8 4 ) . Jensen oversim plified: A reply to Sternberg. Jou rn al o f Social
and Biological Structures, 1, 1 2 7 —1 3 0 .
2 5 3 . Jensen, A. R . ( 1 9 8 4 ) . Review o f Intelligence and national achievement, ed ite d b y R . B.
C attell. Personality and Individual Differences, 5, 4 9 1 —4 9 2 .
2 5 4 . Jensen, A. R . ( 1 9 8 4 ) . S o c io b io lo g y and d ifferen tial psychology: T h e arduou s
clim b from p la u sib ility to p ro o f. In J. R . Royce a n d L . P. M o s (E d s .), Annals of
theoretical psychology (V ol. 2 ). P p . 4 9 —5 8 . N ew Y ork: Plenum .
210
APPENDIX A
2 5 5 . Jensen, A . R . ( 1 9 8 4 ) . T h e black-w hite difference o n the K -A B C : Im p licatio n s
fo r future tests. Journal of Special Education, 18, 3 7 7 —4 0 8 .
2 5 6 . Jensen, A . R . ( 1 9 8 4 ) . O b jectivity an d the gen etics o f IQ : A reply t o Steven
Selden. Phi D elta Kappan, 6 6 , 2 8 4 —2 8 6 .
2 5 7 . Agraw al, N ., Sin ha, S . N ., an d Jensen, A. R . ( 1 9 8 4 ) . E ffects o f in b reed in g on
R aven M a trice s. Behavior Genetics, 14, 5 7 9 —5 8 5 .
2 5 8 . V ernon, P. A ., an d Jensen, A . R . ( 1 9 8 4 ) . In d iv id u al an d group differen ces in
intelligence an d speed o f in fo rm atio n processin g. Personality and Individual
Differences, 5, 4 1 1-—4 23.
1985
2 5 9 . Jensen, A . R . ( 1 9 8 5 ) . C o m p e n sa to ry education an d the theory o f intelligence.
Phi Delta Kappan, 6 6 , 5 5 4 —5 5 8 . R e p rin te d in: S life, B. (E d .), Taking sides: Clashing
views on controversial issues (8 th ed.). G u ilford, C T : D u sh k in .
2 6 0 . Jensen, A . R . ( 1 9 8 5 ) . A rm e d Serv ices V ocation al A p titu d e Battery. Measurement
and Evaluation in Counseling and Development, 18, 3 2 —3 7 .
2 6 1 . Jensen, A . R . ( 1 9 8 5 ) . Review o f the Predictive A b ility Test, A d u lt E d itio n . In
J. V M itch ell, Jr. (E d .), The ninth mental measurements yearbook (V ol. 2 ). L incoln :
U n iversity o f N e b rask a P ress. P p . 1 184—1 1 8 5 .
2 6 2 . Jensen, A . R . ( 1 9 8 5 ) . R eview o f M in n e so ta S p a tia l R elations T e st, R evised
E d itio n . In J. V M itchell, Jr. (E d .), The ninth mental measurements yearbook (V o l. 2).
L in coln : U n iversity o f N e b ra sk a P ress. Pp. 1 0 1 4 —1 0 1 5 .
2 6 3 . Jensen, A. R . ( 1 9 8 5 ) . M e th o d o lo g ic a l and sta tistical techniques fo r the chronom etric stu d y o f m ental abilities. In C . R . R e y n o ld s an d V L. W illso n (E d s.),
Methodological and statistical advances in the study of individual differences. N e w York:
Plenum . P p . 5 1 —116.
2 6 4 . Jensen, A . R . ( 1 9 8 5 ) . R ac e differen ces and T y p e II errors: A c o m m e n t on
B orkow ski an d K rause. Intelligence, 9 , 3 3 —39.
2 6 5 . Jensen, A. R . ( 1 9 8 5 ) . T h e nature o f the black-w hite difference on variou s psy­
chom etric tests: S p e a rm a n s h ypoth esis. Behavioral and Brain Sciences, 8, 1 9 3 —2 1 9 .
2 6 6 . Jensen, A . R . ( 1 9 8 5 ) . T h e black-w h ite difference in g: A ph en om en on in search
o f a theory. Behavioral and Brain Sciences, 8, 2 4 6 —2 6 3 .
2 6 7 . Jensen, A . R . ( 1 9 8 5 ) . H u m p h re y ’s attenuated test o f Spearm an ’s hypoth esis.
Intelligence, 9, 2 8 5 —2 8 9 .
2 6 8 . Jensen, A. R . ( 1 9 8 5 ) . Im m unoreactive theory an d the genetics o f m e n ta l abili­
ty. Behavioral and Brain Sciences, 8, 4 5 3 .
A PP E N D IX
A
211
2 6 9 . C o h n S . J., C arlson , J. S ., and Jensen, A . R . (1 9 8 5 ). S p e e d o f in form ation p r o ­
c e ssin g in acad em ically gifted y o u th s. Personality and Individual Differences, 6,
6 2 1 -6 2 9 .
1986
2 7 0 . Jen sen , A. R . ( 1 9 8 6 ) . Intelligence: "D efin ition ,” m easurem en t, and fu tu re
research. In R . J. Ste rn b erg and D . K . D etterm an ( E d s .) , What is intelligence?
Contemporary viewpoints on its nature and definition. N o rw o o d , N J : Ablex.
2 7 1 . Jen sen , A. R . ( 1 9 8 6 ) . T h e theory o f intelligence. In S . M o d g il and C . M o d g il
(E d s .), H ans Eysenck: Searchingfo r a scientific hasisfor human behavior. L on don : F a lm e r
P re ss.
2 7 2 . Jen sen , A. R . ( 1 9 8 6 ) . g. A rtifact o r reality? Journal o f Vocational Behavior, 2 9 ,
301 -3 3 1 .
2 7 3 . Jen sen , A. R . ( 1 9 8 6 ) . Review o f Academic work and educational excellence: Raising stu­
dent productivity, e d ite d by T. M . T o m lin so n and H . J. W alberg. Educational
Evaluation and Policy Analysis, 8, 4 4 7 —4 5 1 .
2 7 4 . Jen sen , A. R „ an d V ern o n , P. A. ( 1 9 8 6 ) . Jensen’s reaction tim e studies: A reply
t o Longstreth. Intelligence, 10, 1 5 3 —1 7 9 .
1987
2 7 5 . Jen sen , A. R . ( 1 9 8 7 ) . C itation C la ssic : (E d u cab ility a n d gro u p d ifferen ces).
Current Contents: Social & Behavioral Sciences, 19 (4 6 ).
2 7 6 . Jen sen , A. R . ( 1 9 8 7 ) . C itatio n C lassic: (B ia s in m ental te stin g ). Current Contents:
Social & Behavioral Sciences, 1 9 (4 6 ).
2 7 7 Jen sen , A. R . ( 1 9 8 7 ) . Process d iffe ren ce s and in dividual differences in so m e
cognitive tasks. Intelligence, I I , 1 0 7 —1 3 6 .
2 7 8 . Jen sen , A. R . ( 1 9 8 7 ) . U n co n fo u n d in g genetic and n o n sh a re d environm ental
e ffe c ts. Behavioral and Brain Sciences, 10, 2 6 —2 7 .
2 7 9 . Jen sen , A. R . ( 1 9 8 7 ) . T h e p lasticity o f “ intelligence” a t different levels o f
analysis. In J. L o c h h e a d , J. Bishop, a n d D . Perkins ( E d s .) , Thinking: Progress in
research and teaching. Ph iladelph ia: F ra n k lin Institute P ress.
2 8 0 . Jen sen , A. R . ( 1 9 8 7 ) . Individual differen ces in m en tal ability. In J. A. G lo v e r
a n d R . R . R o n n in g (E d s .), A history o f educational psychology. N e w York: P len u m .
2 8 1 . Jen sen , A. R . ( 1 9 8 7 ) . T h e g b eyon d fa c to r analysis. In R . R . R on ning, J. A .
G lover, J. C. C o n o le y , and J. C . W itt (E d s .), The influence o f cognitive psychology on
testing. H illsdale, N J : E rlbaum . P p. 8 7 —1 4 2 .
212
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2 8 2 . Jensen, A . R . (1 9 8 7 ) . D iffe re n tial p sy ch o lo gy : Towards co n se n su s. In M .
M o d g il an d C . M o d g il (E d s .), Arthur Jensen: Consensus and controversy. L ondon:
Falm er Press.
2 8 3 . Jensen, A. R . ( 1 9 8 7 ) . ^ as a focus o f c o n c e rted research e ffo r t [Editorial],
Intelligence, 11, 1 9 3 - 1 9 8 .
2 8 4 . Jensen, A. R . ( 1 9 8 7 ) . Intelligen ce as a fact o f nature. Zeitschrift f ü r Pädagogische
Psychologie, I, 1 5 7 —1 6 9 .
2 8 5 . Jensen, A . R . ( 1 9 8 7 ) . In d iv id u al differences in the H ick p a ra d ig m . In P. A.
V ernon (E d .), Speed of information processing and intelligence. N o r w o o d , N J: Ablex.
2 8 6 . Jensen, A . R . ( 1 9 8 7 ) . M e n ta l chronom etry in the study o f le arn in g disabilities.
Mental Retardation and Learning Disability Bulletin, 15, 6 7 —88.
2 8 7 . Jensen, A . R . ( 1 9 8 7 ) . F u r th e r evidence fo r S p e a rm a n s h y p o th e sis concerning
black-w hite differences on psychom etric tests. The Behavioral and B rain Sciences, 10,
5 1 2-519.
2 8 8 . Jensen, A. R ., and M c G u rk , F. C . J. ( 1 9 8 7 ) . Black-w hite b ias in “ cultural” and
“ n on cu ltu ral” test item s. Personality and Individual Differences, 8, 2 9 5 —3 0 1 .
2 8 9 . N aglieri, J. A., and Jensen, A. R . (1 9 8 7 ). C o m p ariso n o f black-w hite differences
on the W I S C - R and the K A B C : Spearm an s hypothesis. Intelligence, 11, 2 1 —43.
1988
2 9 0 . Jensen, A . R . ( 1 9 8 8 ) . M o n g o lo id m ental ab ility : E volution o r culture? Mensa
Research Bulletin, 24, 2 3 —2 5 .
2 9 1 . Jensen, A. R . ( 1 9 8 8 ) . R eview o f Practical intelligence: Nature and origins o f competence
in the everyday world, ed ited by R . J. Stern b erg an d R . K. W agner. Personality and
Individual Differences, 9, 1 9 9 —2 0 0 .
2 9 2 . Jensen, A . R . (1 9 8 8 ) . S p e e d o f in fo rm ation pro cessin g and p o p u la tio n differ­
ences. In S . H . Irvine (E d .), The cultural context of human ability. L ondon:
C am brid ge U niversity P ress.
2 9 3 . Jensen, A. R . (1 9 8 8 ). Review o f the A rm ed Services Vocational A p titude Battery.
In J. T. K ap es and M . M . M a stie (E ds.), A counselor’s guide to career assessment instru­
ments. Alexandria, VA: N a tio n a l Career D evelopm ent A ssociation. P p. 5 9 —62.
2 9 4 . Jensen, A . R . ( 1 9 8 8 ) . Se x differences in arith m etic co m p u tatio n an d reasoning
in prep u b ertal boys an d girls. Behavioral and Brain Sciences, 11, 1 9 8 —1 9 9 .
2 9 5 . Jensen, A . R ., and F au lstich , M . E . ( 1 9 8 8 ) . Psychom etric g in b lack and white
prison ers. Personality and Individual Differences, 9, 9 2 5 —9 28.
2 9 6 . Jensen, A . R ., L arso n , J., a n d Paul, S. M . ( 1 9 8 8 ) . P sych om etric g and m ental
processin g speed on a sem an tic verification test. Personality and Individual
Differences, 9, 2 4 3 —2 5 5 .
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A PPEN D IX A
2 9 7 . Jensen, A. R ., Saccu zzo, D. P., an d Larson, G . E . ( 1 9 8 8 ) . E quatin g th e Standard
an d A d van ced F o rm s o f the R aven P rogressive M atrices. Educational and
Psychological Measurement, 4 8 , 10 9 1 —109 5 .
2 9 8 . C oh n , S . J., C o h n , C . M . G ., an d Jensen, A. R . ( 1 9 8 8 ) . M yopia a n d intelligence:
A pleio tro p ic relationship? H um an Genetics, 8 0 , 5 3 —5 8 .
2 9 9 . K ranzler, J. H ., W h an g , P. A ., an d Jensen, A. R . ( 1 9 8 8 ) . Jensens u se o f the H ick
p aradigm : V isu al attention an d ord er effects. Intelligence, 12, 3 7 1 —3 9 1 .
1989
3 0 0 . Jensen, A . R . ( 1 9 8 9 ) . T h e relation sh ip betw een learning an d intelligence.
Learning and Individual Differences, I, 3 7 —6 2.
3 0 1 . Jensen, A . R .
( 1 9 8 9 ) . P h ilip
E w art V e rn o n
(1 9 0 5 -1 9 8 7 )
[O b itu ary ],
Psychologist, 4 4 , 8 4 4 .
3 0 2 . Jensen, A. R . ( 1 9 8 9 ) . “ R e v ise d ” U pdated. R e v ie w o f Intelligence: Its structure,
growth and action, by R . B. C attell. Contemporary Psychology, 3 4, 1 4 0 —1 4 1 .
3 0 3 . Jensen, A . R . ( 1 9 8 9 ) . R a is in g I Q w ithout in creasin g g ? A review o f The
Milwaukee Project: Preventing mental retardation in children at risk. Developmental Review, 9,
234^258.
3 0 4 . Jensen, A. R . ( 1 9 8 9 ) . “ T o ta l perceived value” as th e basis o f asso rta tiv e mating
in hum ans. Behavioral and Brain Sciences, 12, 5 3 1 .
3 0 5 . Jensen, A. R . ( 1 9 8 9 ) . N e w fin d in g s on the in tellectually gifted. N ew Horizons,
30, 7 3 -8 0 .
3 0 6 . Jensen, A. R ., C o h n , S . J., an d C o h n , C. M . G . ( 1 9 8 9 ) . Speed o f in form ation
p ro ce ssin g in academ ically g ifte d youths a n d th eir siblings. Personality and
Individual Differences, 10, 2 9 —3 4 .
3 0 7 . Buckhalt, J., an d Jensen, A . R . ( 1 9 8 9 ). T h e British Ability Scales S p e e d o f
In fo rm a tio n P rocessin g su b te st: W h at d o es
it measure? British Journal of
Educational Psychology, 5 9 , 1 0 0 —1 0 7 .
3 0 8 . K ranzler, J. H ., an d Jensen, A . R . ( 1 9 8 9 ). In sp e c tio n time and intelligence: A
m eta-analysis. Intelligence, 13, 3 2 9 —3 4 7 .
3 0 9 . R eed, T. E ., an d Jensen, A. R . ( 1 9 8 9 ) . S h o rt la te n cy visual evoked potentials
( V E P s ) , visual tract speed, a n d intelligence. S ig n ific a n t correlations. A bstract.
Behavior Genetics, 19, 7 7 2 —7 7 3 .
1990
3 1 0 . Jensen, A. R . ( 1 9 9 0 ) . Sp eed o f in form ation p r o c e ssin g in a c alc u la tin g prodi­
gy. Intelligence, 14, 2 5 9 —2 7 4 .
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A P P E N D IX A
3 1 1 . Jensen, A. R . ( 1 9 9 0 ) . Straight h isto ry . Review o f Schools as sorters: Lewis M . Terman,
applied psychology, and the intelligence testing movement, 1 8 9 0 —1 9 3 0 , by P. D . C h ap m an .
Contemporary Psychology, 35, 1 1 4 7 —1 1 4 8 .
3 1 2 . Jensen, A. R ., a n d R e e d ,T . E. ( 1 9 9 0 ) . Sim ple reaction tim e as a su p p re sso r vari­
able in the ch ron om etric study o f intelligence. Intelligence, 14, 3 7 5 —3 8 8 .
1991
3 1 3 . Jensen, A. R . ( 1 9 9 1). Sp earm an s g an d the p ro b lem o f educational equality.
Oxford Review o f Education, 1 7 ( 2 ) , 1 6 9 —187.
3 1 4 . Jensen, A. R . ( 1 9 9 1). General m e n ta l ability: F ro m psychom etrics t o b iology .
Psychodiagnostique, 16, 1 3 4 —144.
3 1 5 . Jensen, A. R . ( 1 9 9 1 ) . Speed o f c o gn itiv e processes: A chronom etric a n c h o r for
psychom etric te s ts o f g. Psychological Test Bulletin, 4, 5 9 —7 0 .
3 1 6 . Jensen, A. R . ( 1 9 9 1). I Q and S c ie n c e : T h e m y ste rio u s Burt affair. The Public
Interest, 105,
93—106.
3 1 7 . Jensen, A. R . ( 1 9 9 1 ) . Review o f
U. S. race relations in
the 1 9 8 0 s and 1 9 9 0 s: Challenges
and alternatives, e d ite d by G . E . T h o m a s . Personality and Individual Differences, 12,
321 -3 2 2 .
3 1 8 . Jensen, A. R . ( 1 9 9 1 ). S p irm an o v ^ fa c to r: Veze iz m e d u psihom etrije i b io lo g ije. Psihologija, 2 4 , 1 6 7 —193.
3 1 9 . Kranzler, J. H „ a n d Jensen, A . R . ( 1 9 9 1). T h e n atu re o f p sy ch o m etric g:
U n itary p ro c e ss
o r a n um ber o f
independent processes? Intelligence,
15,
397 -4 2 2 .
3 2 0 . Kranzler, J. H ., a n d Jensen, A. R . ( 1 9 9 1). U nitary g: U n qu estion ed p o s tu la te or
em pirical fact? Intelligence, 15, 4 3 7 —4 4 8 .
3 2 1 . R eed, T. E., an d Jensen, A. R . ( 1 9 9 1 ). A rm nerve c o n d u c tio n velocity ( N C V ) ,
brain N C V , re a c tio n time, and intelligence. Intelligence, 15, 3 3 —47.
1992
3 2 2 . Jensen, A. R . ( 1 9 9 2 ) . U n d e rsta n d in g g in term s o f inform ation p ro ce ssin g.
Educational Psychology Review, 4, 2 7 1 —3 0 8 .
3 2 3 . Jensen, A. R . ( 1 9 9 2 ) . S p e a rm a n s hypothesis: M e th o d o lo g y an d evidence.
Multivariate Behavioral Research, 2 7 , 2 2 5 —2 3 3 .
3 2 4 . Jensen, A. R . ( 1 9 9 2 ) . M ore on P sych om etric g a n d “ Spearm ans h y p o th esis.”
Multivariate Behavioral Research, 2 7 , 2 5 7 —2 6 0 .
3 2 5 . Jensen, A. R . ( 1 9 9 2 ) . Scientific f r a u d or false acc u sa tio n s? T h e case o f Cyril
Burt. In D. J. M ille r and M . H e r s e n (E d s.), Research findings in the behavioral and
biomedical sciences. N e w York: W iley a n d Sons, Inc.
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A
215
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tim e. Personality and Individual Differences, 13, 8 6 9 —8 8 2 .
3 2 7 . Jensen , A . R . ( 1 9 9 2 ) . Preface. In R . Pearson (E d .), Shockley on race, eugenics, and dysgenics. W ashington, D C : Scott-T o w n sen d . P p . I —13.
3 2 8 . Jensen , A . R . ( 1 9 9 2 ) . M e n tal ability: C ritica l thresholds an d so cial policy.
Jou rn al of Social, Political and Economic Studies, I 7, I —11.
3 2 9 . Jensen , A. R . ( 1 9 9 2 ) . T h e C y ril B u rt scan dal, research tab oos, an d the m edia.
The General Psychologist, 2 8 , 16—2 1 .
3 3 0 . Jensen , A. R . (1 9 9 2 ) . T h e relation betw een in fo rm ation p ro c e ssin g tim e and
r ig h t/w ro n g responses. American Journal on Mental Retardation, 9 7, 2 9 0 —2 9 2 .
3 3 1 . Jen sen, A. R . ( 1 9 9 2 ) . V ehicles o f g. Psychological Science, 3, 2 7 5 —2 7 8 .
3 3 2 . Jensen, A . R ., and R eed , T. E . ( 1 9 9 2 ) . T h e correlatio n betw een reaction tim e
an d the pon d éral index. Perceptual and Motor Skills, 73, 8 4 3 —8 4 6 .
3 3 3 . Jen sen, A. R ., and W ilso n , M . ( 1 9 9 2 ) . H e n ry Felix K aiser ( 1 9 2 7 —1 9 9 2 ). In
Memoriam, pp. 8 8 —9 1 . Berkeley: U niversity o f C aliforn ia.
3 3 4 . R eed , T. E ., and Jensen, A . R . ( 1 9 9 2 ) . C o n d u c tio n velocity in a brain nerve
p ath w ay o f n o rm al ad u lts correlates w ith intelligence level. Intelligence, 16,
2 59-278.
1993
3 3 5 . Jen sen , A . R . ( 1 9 9 3 ) . Psych om etric g an d achievem ent. In B. R . G iffo rd (E d .),
Policy perspectives on educational testing. N orw ell, M A : Kluw er A cad em ic Publishers.
Pp. 117-227.
3 3 6 . Jen sen , A . R . ( 1 9 9 3 ) . T e st validity: g versus “ tacit knowledge.” Current Directions
in Psychological Science, 2, 9 —10.
3 3 7 . Jen sen , A . R . ( 1 9 9 3 ) . W h y is reaction tim e correlated w ith psychom etric g l
Current Directions in Psychological Science, 2, 5 3 —5 6 .
3 3 8 . Jensen, A . R . ( 1 9 9 3 ) . S p e a rm a n s h yp oth esis tested with chron om etric infor­
m a tio n processin g task s. Intelligence, 1 7, 4 7 —7 7 .
3 3 9 . Jen sen , A . R . ( 1 9 9 3 ) . S p e a rm a n s g: L in k s betw een psychom etrics an d biology.
Annals of the New York Academy o f Sciences, 7 0 2 , 1 0 3 —131.
3 4 0 . Jensen, A . R „ an d Sinha, S . N . ( 1 9 9 3 ) . P h y sical correlates o f h um an intelli­
gence. In P. A . V ern on (E d .), Biological approaches to the study of human intelligence.
N o r w o o d , N J: A blex. Pp. 1 3 9 —2 4 2 .
3 4 1 . Jensen , A. R ., and W h an g , P. A . ( 1 9 9 3 ) . R e ac tio n tim es an d intelligence: A
c o m p a riso n o f C h in ese-A m erican an d A n glo-A m erican children. Journal of
Biosocial Science, 2 5 , 3 9 7 —4 1 0 .
216
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A
3 4 2 . K ran zler, J. H ., an d Jensen, A. R . ( 1 9 9 3 ) . Psych om etric g is still n ot u n itary
a fte r elim in atin g
su p p o se d
“ im p u r itie s” : F u rth e r com m en t on C a rro ll.
Intelligence, I 7, I I —14.
3 4 3 . R e e d , T . E., and Jen sen , A. R . ( 1 9 9 3 ) . C h o ice reaction tim e and visual path w ay
nerve con du ctio n velocity both c o rre late with intelligence but ap pear n o t to
correlate with each other: Im p licatio n s fo r in fo rm ation processing. Intelligence,
17, 1 9 1 - 2 0 3 .
3 4 4 . R e e d , T. E., an d Jen sen , A. R . ( 1 9 9 3 ) . C ran ial capacity: N e w C au casian data
an d com m ents o n R u sh to n s claim ed M o n g o lo id - C a u c a so id brain-size d iffe r­
ences. Intelligence, I 7 , 4 2 3 —4 3 1 .
3 4 5 . R e e d , T. E., and Jen sen, A. R . ( 1 9 9 3 ) . A so m a to se n so ry latency betw een the
th alam u s and c o rte x also correlates w ith level o f intelligence. Intelligence, I 7,
4 43-4 5 0 .
1994
3 4 6 . Jen sen , A. R . ( 1 9 9 4 ) . Afterw ord: D e a fn e ss and the nature o f m ental ab ilities.
In J. P. Braden, Deafness, deprivation, and I Q . N e w Y ork: Plen um . Pp. 2 0 3 —2 0 8 .
3 4 7 . Jen sen , A. R . ( 1 9 9 4 ) . P h logiston, an im a l m agnetism , an d intelligence. In D . K .
D ette rm an (E d .), Current topics in human intelligence, Vol. 4 : Theories of intelligence.
N o rw o o d , N J: A b lex. P p. 2 5 7 —2 8 4 .
3 4 8 . Jen sen , A. R . ( 1 9 9 4 ) . Review o f Intelligence (2 n d ed.), by N . Brody. American
Jo u rn al on Mental Retardation, 98, 6 6 3 —6 6 7 .
3 4 9 . Jen sen , A. R . ( 1 9 9 4 ) . Reaction tim e. In R . J. C o rsin i (E d .), Encyclopedia of
Psychology, 2n d. ed. V ol. 3. N ew Y ork: W iley. Pp. 2 8 2 —2 8 5 .
3 5 0 . Jen sen , A. R . ( 1 9 9 4 ) . H um ph reys’s “ behavioral rep erto ire” an epiph en om en on
o f g. Psychological Inquiry, 5, 2 0 8 —2 1 0 .
3 5 1 . Jen sen , A. R . ( 1 9 9 4 ) . Francis G a lto n . In R . J. Ste rn b erg (E d .), Encyclopedia of
Intelligence.V‘o l. I . N e w York: M a c m illa n . P p. 4 5 7 —4 6 3 .
3 5 2 . Jen sen , A. R . ( 1 9 9 4 ) . Charles E d w a rd Spearm an . In R . J. Sternberg (E d .),
Encyclopedia of Intelligence. Vol. 2. N e w Y o rk : M acm illan . P p . 1 0 0 7 —1 0 1 4 .
3 5 3 . Jen sen , A. R . ( 1 9 9 4 ) . H a n s Jurgen E y se n ck . In R . J. Ste rn b erg (E d .), Encyclopedia
o f Intelligence. V ol. I . N e w York: M a c m illa n . Pp. 4 1 6 ^ 1 1 8 .
3 5 4 . Jen sen , A. R . ( 1 9 9 4 ) . R ace and I Q sco re s. In R . J. Ste rn b erg (E d .), Encyclopedia
o f Intelligence. V ol. 2 . N e w York: M a c m illa n . Pp. 8 9 9 —9 0 7 .
3 5 5 . Jensen , A. R . ( 1 9 9 4 ) . Psychom etric g related to differen ces in h ead size.
Personality and Individual Differences, 1 7, 5 9 7 —6 0 6 .
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3 5 6 . Jensen, A. R . ( 1 9 9 4 ) . Paroxysm s o f denial. National Review, 4 6 (D ec. 5 ), 4 8 —5 0 .
R ep rin ted in: Jacoby, R ., an d G lau berm an , N . (E d s .), The Bell Curve debate:
History, documents, opinion. N e w Y ork : R a n d o m H o u se , 1 9 9 5 .
3 5 7 . Jensen, A. R ., an d Joh n son ,
F. W. ( 1 9 9 4 ) . R ace an d sex differences in h e a d size
an d IQ . Intelligence, 1 8, 3 0 9 —3 3 3 .
3 5 8 . Jensen, A. R ., an d R uddell, R . B. ( 1 9 9 4 ) . G uy T h o m a s Buswell. In Memoriam.
Berkeley: U n iversity o f C aliforn ia. P p . 4 6 —49.
3 5 9 . Jensen, A. R ., an d W eng, J.-J. ( 19 9 4 ) . W h a t is a g o o d g? Intelligence, 18, 2 3 1—2 5 8 .
3 6 0 . Jensen, A. R ., an d W h an g , P. A . ( 1 9 9 4 ) . Speed o f accessin g arithm etic fac ts in
lon g-term m em ory: A co m p ariso n o f C h inese-A m erican an d A n glo-A m erican
children. Contemporary Educational Psychology, 19, I —12.
3 6 1 . Jensen, A. R ., an d W ilson , M . ( 1 9 9 4 ) . H en ry Felix K aiser ( 1 9 2 7 —1 9 9 2 )
[O bitu ary]. American Psychologist, 4 9 , 1 0 8 5 .
3 6 2 . K ranzler, J. H ., W h an g , P. A., an d Jensen, A. R . ( 1 9 9 4 ) . T a sk com plexity an d
the speed an d efficien cy o f elem ental in form ation pro cessin g: A n oth er lo o k at
the nature o f intellectual gifte d n e ss. Contemporary Educational Psychology,
19,
44 7 -4 5 9 .
3 6 3 . Shaughnessy, M . F. ( 1 9 9 4 ). A n interview with A rth u r R . Jensen. The School Field,
4, 1 2 9 - 1 5 4 .
1995
3 6 4 . Jensen, A. R . ( 1 9 9 5 ) . P sy ch ological research on race differences [C o m m e n t].
American Psychologist, SO, 4 1 —4 2 .
3 6 5 . Jensen, A. R . ( 1 9 9 5 ) . W anted: A u n ified theory o f individual and g r o u p d if­
ferences. [A b stract]. Behavior Genetics, 2 5 , 2 7 2 .
3 6 6 . Jensen, A. R . ( 1 9 9 5 ) . I Q an d scien ce: T h e m y steriou s B u rt affair. In N . J.
M ack in to sh (E d .), C yril Burt: Fraud orjram ed? O x fo rd : O x fo r d U niversity P ress.
1996
3 6 7 . Jensen, A. R . ( 1 9 9 6 ) . Secular tren d s in IQ : A d d itio n al hypotheses. In D . K .
D etterm an (E d .),
Current topics in human intelligence, Ksl.
4: The environment.
N o rw o o d , N J: A blex. Pp. 1 4 7 —1 5 0 .
3 6 8 . Jensen, A. R . ( 1 9 9 6 ) . In spection T im e and g [L etter]. Nature, 3 8 1 , 7 2 9 .
3 6 9 . Jensen, A. R . ( 1 9 9 6 ) . T h e locu s o f b iological g. In I. M ervield e (E d .), Abstracts
o f the 8th European Conference on Personality, U niversity o f G h en t, Belgium , Ju ly I I ,
1996, p. 54.
218
APPENDIX A
3 7 0 . Jensen, A . R . ( 1 9 9 6 ) . G ifte d n e ss and gen ius: C ru cial differences. In C . P.
Ben bow an d D. L u b in sk i (E d s .), Intellectual talent: Psychometric and social issues,
B altim ore: Joh n s H o p k in s U niversity Press. P p . 3 9 3 —4 1 1 .
3 7 1 . Jensen, A . R . ( 1 9 9 6 ). R eview o f Genetics and experience, by R . P lo m in . Journal of
Social and Evolutionary Systems, 1 9, 3 0 7 —3 1 1 . R e p rin te d in: European Sociobiological
Newsletter, M a y 1 9 9 7 , N o . 4 4 , 2 4 —2 8 .
1997
3 7 2 . Jensen, A . R . ( 1 9 9 7 ) . T h e p u z zle o f non gen etic variance. In R . J. Ste rn b erg and
E.
L.
G rig o ren k o
( E d s .) ,
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C am bridge:
C am b rid g e U niversity P re ss. Pp. 4 2 —88.
3 7 3 . Jensen, A . R . ( 1 9 9 7 ). T h e n europ h y siology o f g. In C . C o o p e r an d V V arm a
(E d s .), Processes in individual differences. L o n d o n : R ou tledge. P p. 1 0 8 —1 2 5 .
3 7 4 . Jensen, A . R . ( 1 9 9 7 ). Psy ch om etric g and the race question. In J. K in g m a and
W. T o m ic (E d s.), Reflections on the concept of intelligence. Greenw ich, C T : JA I Press.
Pp. 1 - 2 3 .
3 7 5 . Jensen, A . R . ( 1 9 9 7 ). In tro d u ctio n (to se ctio n o n intelligence). In H . N y b o rg
(E d .), The scientific study of human nature: Tribute to H an s J. Eysenck at eighty. N e w York:
Elsevier. P p . 2 1 5 - 2 2 0 ) .
3 7 6 . Jensen, A . R . ( 1 9 9 7 ). T h e psychom etrics o f intelligence. In H . N y b o r g (E d .),
The scientific study of human nature: Tribute to H a n s J. Eysenck at eighty. N e w York:
Elsevier. P p . 2 2 1 —2 3 9 .
3 7 7 . Jensen, A . R . ( 1 9 9 7 ). E y se n ck as teacher an d m en tor. In H . N y b o r g (E d .), The
scientific study of human nature: Tribute to H ans J. Eysenck at eighty. N e w Y ork: Elsevier.
Pp. 543-559.
3 7 8 . Jensen, A . R . ( 1 9 9 7 ) . Intelligence. In S . P. P ark er F (E d .), Encyclopedia of science
and technology. 8th edition . N e w York: M c G ra w -H ill. Pp. 2 8 8 —2 8 9 .
1998
3 7 9 . Jensen, A . R . ( 1 9 9 8 ). The g factor. W estport, C T : Praeger.
3 8 0 . Jensen, A . R . ( 1 9 9 8 ). S p e a rm a n s law o f d im in ish in g returns. In A . S e n and A.
K . S e n (E d s .), Challenges of contemporary realities: A psychological perspective. N e w Delhi:
N e w A g e Intern ational, L td .
3 8 1 . Jensen, A . R . ( 1 9 9 8 ). T h e g fac to r in the d esign o f education. In R . J. Sternberg
an d W . M .. W illiam s (E d s .), Intelligence, instruction, and assessment. H illsd ale , N J:
E rlb au m . P p. I l l —131
3 8 2 . Jensen, A . R . ( 1 9 9 8 ) . T h e su p p re ssed relation sh ip between I Q an d the reaction
tim e slo p e param eter o f the H ic k function. Intelligence, 26, 4 3 —5 2 .
APP E N D IX
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219
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3 8 5 . Jen sen , A. R . ( 1 9 9 9 ) . Review o f Psychological testing of American minorities, b y R . J.
S a m u d a . Personality and Individual Differences, 2 6 , 1 143—1 1 4 5 .
3 8 6 . Jen sen , A. R . ( 1 9 9 9 ) . Review o f Intelligence: A new look, b y H . J. Eysenck. Galton
Institute Newsletter, 3 2 , 6—8.
3 8 7 . C a ry l, P. G., D eary, I. J., Jensen, A . R ., N eubauer, A. C ., a n d Vickers, D. ( 1 9 9 9 ) .
In fo rm a tio n p ro c e ssin g approaches t o intelligence: P r o g r e ss and p ro sp e c ts. In
I. M ervielde, I. D ea ry , F. de Fruyt, a n d F. O ste n d o rf ( E d s .) , Personality psycholo­
gy in Europe: Volume 7. T ilb u rg U n iv e rsity Press. Pp. 1 8 1 —2 1 9 .
2000
3 8 8 . Jen sen , A. R . ( 2 0 0 0 ) . H an s E y s e n c k s final thoughts o n intelligence. S p e c ia l
review o f Intelligence: A New Look, b y H . J. Eysenck. Personality and Individual
Differences, 2 8 , 1 9 1 —1 9 4 .
3 8 9 . Je n se n , A. R . ( 2 0 0 0 ) . Review o f Em inent Creativity, Everyday Creativity, and Health,
e d ite d by M . A. R u n c o and R . R ic h a rd s. Personality and Individual Differences, 2 8 ,
198 -1 9 9 .
3 9 0 . Je n se n , A. R . ( 2 0 0 0 ) . Elem entary cogn itiv e tasks a n d psychom etric g. In A .
H a r r is (E d .), Encyclopedia of Psychology. N e w York: A P A / O x fo r d U niversity P re ss.
Pp. 156-157.
3 9 1 . Jen sen , A. R . ( 2 0 0 0 ) . Twins. In A . H a r r is (E d.), Encyclopedia of Psychology. N e w
Y o rk : A P A /O x fo r d U niversity P r e ss. P p . 1 3 2 - 1 3 5 .
3 9 2 . Je n se n , A. R . ( 2 0 0 0 ) . Charles E . S p e a rm a n : Founder o f the L on d on S c h o o l.
Galton Institute Newsletter, 3 6 , 2—4 .
3 9 3 . Je n se n , A. R . ( 2 0 0 0 ) . Testing: T h e d ilem m a o f g r o u p differences.
Psychology,
Public Policy, and Law , 6, 121—127.
3 9 4 . Je n se n , A. R . ( 2 0 0 0 ) . H a n s E ysen ck: A p o stle o f the L o n d o n School. In G . A .
K im b le and M . W ertheim er ( E d s .) , Portraits of Pioneers in Psychology. V o l. 4 .
W ashin gton, D C : A m erican P sy c h o lo g ic al A sso ciatio n ; and M ahw ah, N J :
E rlb au m . Pp. 3 3 8 —3 5 7 .
3 9 5 . Jen sen , A. R . ( 2 0 0 0 ) . Charles S p e a rm a n . Discoverer o f g . In G . A. K im b le an d
M . W ertheim er ( E d s .) , Portraits o f Pioneers in Psychology. V o l. 4 . W ashington, D C :
A m erican P sy ch o lo gical A ssociation ; an d Mahwah, N J : E rlb au m . Pp. 9 2 —1 I I .
220
APPENDIX A
3 9 6 . Jensen, A . R . ( 2 0 0 0 ) . W as w ir über den ¿ - F a k to r wissen (u n d nichtw issen). In
K . Sch w eizer (E d .). Intelligenze u n i kognition: D ie kognitiv-biologische Perspektive der
Intelligenz. L an d au : V erlag fü r Em pirische P ä d a g o g ik . Pp. 13—3 6 .
3 9 7 . Jensen, A . R . ( 2 0 0 0 ) . T h e g factor: P sy ch o m etrics and b io lo g y . N ovartis
F o u n d a tio n S y m p o siu m N o . 2 3 3 . The nature o f intelligence. C h ich ester, England:
W iley. P p . 3 7 - 5 7 .
3 9 8 . Jensen, A . R . ( 2 0 0 0 ) . S o m e recent overlooked research on the sc ie n tific basis o f
The Bell Curve. C o m m e n tary o n R eifm an o n Bell-Curve. Psycoloquy, 11 (1 0 6 ).
3 9 9 . Jensen, A . R . ( 2 0 0 0 ) . “ T h e g F acto r" is a b o u t variance in h u m an abilities, not
a cognitive theory o f m en tal structure. R e p ly to A nd erson. Psycoloquy, 11
(0 4 1 ).
4 0 0 . Jensen, A . R . ( 2 0 0 0 ) . A n ih ilistic p h ilo so p h y o f science fo r a scientific psy ­
chology? R ep ly to B arrett. Psycoloquy, 11 ( 0 8 8 ) .
4 0 1 . Jensen, A . R . ( 2 0 0 0 ) . N am e -c allin g is a d isa p p o in tin g su b stitu te fo r real criti­
cism . R e p ly to Brace. Psycoloquy, 11 (0 0 9 ).
4 0 2 . Jensen, A . R . ( 2 0 0 0 ) . A rtific ia l intelligence a n d g theory con cern different phe­
n om ena. R ep ly to B rin g sjord . Psycoloquy, 11 ( 0 8 6 ) .
4 0 3 . Jensen, A . R . ( 2 0 0 0 ) . T h e heritability o f g p ro v e s both its b io lo g ic a l relevance
an d its transcendence over specific cognitive ab ilities. R eply t o B ub. Psycoloquy,
11 ( 0 8 5 ) .
4 0 4 . Jensen, A . R . ( 2 0 0 0 ) . P ro c e ssin g speed, in sp e c tio n time, and n erve conduction
velocity. R ep ly to B urn s. Psycoloquy, 11 ( 0 1 9 ) .
4 0 5 . Jensen, A . R . ( 2 0 0 0 ) . T h e u b iq u ity o f m en tal sp e e d and the c e n trality o f work­
ing m em ory. R eply to C o n w ay et al. Psycoloquy, 11 (0 3 8 ).
4 0 6 . Jensen, A . R . ( 2 0 0 0 ) . Is there a self-aw areness o f on es own g level? Reply to
D em etrio u . Psycoloquy, 11 (0 4 0 ) .
4 0 7 . Jensen, A . R . (2 0 0 0 ) . M ix in g up eugenics a n d G alton ’s legacy t o research on
intelligence. R eply to Fancher. Psycoloquy, 11 ( 0 1 7 ) .
4 0 8 . Jensen, A . R . ( 2 0 0 0 ) . Psy ch om etric sce p ticism . R e p ly to H a rr in g to n . Psycoloquy,
11 ( 0 3 9 ) .
4 0 9 . Jensen, A . R . (2 0 0 0 ) . T h e lo c u s o f the m o d ifia b ility o f ¿ is m o s tly biological.
R e p ly to H u n t. Psycoloquy, 11 (0 1 2 ).
4 1 0 . Jensen, A . R . ( 2 0 0 0 ) . A “ sim p le st cases” a p p ro a c h to exploring th e neural basis
o f g. R e p ly to Ingber. Psycoloquy, 11 (0 2 3 ).
4 1 1 . Jensen, A . R . ( 2 0 0 0 ) . A fu z z y boundary o f ra c ia l classification attenuates I Q
differen ce. R eply to Jo rio n . Psycoloquy, 11 ( 0 2 2 ) .
4 1 2 . Jensen, A . R . ( 2 0 0 0 ) . A p o tp o u rri o f ¿ -re la te d topics. R e p ly t o Kovacs and
Pleh. Psycoloquy, 11 ( 0 8 7 ) .
APP ENDIX A
221
4 1 3 . Jensen, A. R . ( 2 0 0 0 ) . I Q tests, psychom etric a n d chronom etric g , a n d achieve­
m ent. R eply to Kush. Psycoloquy, 1 1 (0 1 4 ).
4 1 4 . Jensen, A. R . ( 2 0 0 0 ) . R ace d ifferen ces, g, and th e “ default h y p oth esis.” Reply
to L o c u rto . Psycoloquy, 11 ( 0 0 4 ) .
4 1 5 . Jensen, A. R . ( 2 0 0 0 ) . C ogn itive com ponents a s chronom etric p r o b e s to brain
processes. R e p ly to M a ck in to sh . Psycoloquy, 11 ( O i l ) .
4 1 6 . Jensen, A. R . ( 2 0 0 0 ) . Beh avioral an d biological phenom ena equ ally “ real” and
related. R e p ly to Partridge. Psycoloquy, 11 ( 0 1 8 ) .
4 1 7 . Jensen, A. R . ( 2 0 0 0 ) . “ B io lo g ica l determ inism ” as an ideological buzz-w ord.
R eply to R ay m o n d . Psycoloquy, 11 (0 2 1 ).
4 1 8 . Jensen, A. R . (2 0 0 0 ) . N o th in g “ m ystifying” a b o u t psychom etric g . R eply to
R ich ardson . Psycoloquy, 11 ( 0 4 2 ) .
4 1 9 . Jensen, A. R . ( 2 0 0 0 ) . C o rre la te d vectors, g, a n d the “Jensen effect.” R eply to
R ush ton . Psycoloquy, 10 ( 0 8 2 ) .
4 2 0 . Jensen, A. R . (2 0 0 0 ) . E v o k e d poten tials, testo ste ro n e, and g. R e p ly to Tan.
Psycoloquy, 10 (0 8 5 ) .
4 2 1 . Jensen, A. R . ( 2 0 0 0 ). E v o k e d brain p o ten tials and g. R ep ly t o Verleger.
Psycoloquy, 10 (0 8 4 ) .
4 2 2 . N y b o rg , H ., an d Jensen, A. R . ( 2 0 0 0 ) , T estostero n e levels as m o d ifie rs o f psy­
chom etric g. Personality and Individual Differences, 2 8 , 6 0 1 —607.
4 2 3 . N y b o rg , H . an d Jensen, A. R . ( 2 0 0 0 ) . Black-w hite differences o n variou s psy­
chom etric tests: Spearm an ’s h y p o th esis tested o n Am erican arm ed services vet­
erans. Personality and Individual Differences, 2 8, 5 9 3 —5 9 9 .
2001
4 2 4 . Jensen, A. R . ( 2 0 0 1 ) . S p e a rm a n s hypothesis. In S . M essick and J. C o llis (E ds.),
Intelligence and personality: Bridging the gap in theory and measurement. M ah w ah , N J:
E rlbaum . P p. 3 —2 5
4 2 5 . Jensen, A. R . ( 2 0 0 1 ) . M isle a d in g caricatures o f Jensen’s statistics: A reply to
K aplan . Chance, 14, 2 2 —2 6 .
4 2 6 . N y b o rg , H ., an d Jensen, A. R . ( 2 0 0 1 ) . O c c u p a tio n an d income re la te d to psy­
chom etric g. Intelligence, 2 9 , 4 5 —5 5 .
2002
4 2 7 . Jensen, A. R . ( 2 0 0 2 ) . G a lto n ’s legacy to research on intelligence ( T h e 1999
G alto n L ectu re). Journal of Biosocial Science, 3 4, 1 4 5 —1 72.
4 2 8 . Jensen, A. R . (2 0 0 2 ) . G en eral cognitive ab ility (g factor) asse ssm e n t. In R .
F em an dos-B allesteros (E d .), Encyclopedia of Psychological Assessment. L o n d o n : Sage.
222
A PPEN D IX A
4 2 9 . Jensen, A. R . ( 2 0 0 2 ) . Review o f Intelligence testing and minority students: Foundations,
performance factors, and assessment issues, by R . R . V ale n c ia and L. A . Su zu k i.
Intelligence, 3 0 , 2 1 6 —2 1 7 .
4 3 0 . Jensen, A. R . ( 2 0 0 2 ) . Psychom etric g: D efinition a n d substan tiation. In R . J.
Sternberg an d E . L . G rigorenko ( E d s .) , The generalfa c to r o f intelligence: H o w general
is it? M ahw ah, N J : Erlbaum . P p. 3 9 —5 4 .
In Press
4 3 1 . Jensen, A. R . (in press). R e g u la ritie s in Sp e a rm a n ’s Law o f D im in ish in g
R eturns. Intelligence.
4 3 2 . Jensen, A. R . (in p re ss). D o ag e -g ro u p differences o n m e n tal tests im ita te racial
differences? Intelligence.
4 3 3 . Jensen, A. R . (in p re ss). V ocab ulary an d general intelligence: C o m m e n tary on
B lo o m s H ow children learn the meanings i f words ( 2 0 0 0 ) . Behavioral and Brain Sciences.
4 3 4 . Jensen, A. R . (in p re ss). T h e m e n ta l chronom etry o f giftedness. In D . Booth e
and J. C. S tan le y (E d s.), Giftedness and cultural diversity.
4 3 5 . R ush ton , J. P., a n d Jensen, A. R . (in p re ss). A frica n -W h ite I Q differences from
Z im babw e on th e W echsler In telligen ce Scale for C h ild re n — Revised. Personality
and Individual Differences.
APPENDIX B
MAINSTREAM S C I E N C E
ON I N T E L L I G E N C E 1
T h e M eaning and M easurement o f Intelligence
1. Intelligence is a very general mental capability that, am ong
other things, involves the ability to reason, plan, solve problems,
think abstractly, comprehend com plex ideas, learn quickly and
learn from experience. It is n ot merely book learning, a narrow
academic skill, or test-taking sm arts. Rather, it reflects a broader
and deeper capability for comprehending our surroundings—
“ catching on,” “ m aking sense” o f things, or “ figuring out” what
to do.
2. Intelligence, so defined, can be measured, and intelligence
tests measure it well. T h e y are among the m o st accurate (in
technical term s, reliable and valid) o f all psychological tests and
assessments. T h ey do n ot m easure creativity, character, person­
ality, or other im portant differences among individuals, nor are
they intended to.
3. W hile there are different types o f intelligence tests, they all
measure the same intelligence. Som e use words or numbers and
require specific cultural know ledge (like vocabulary). Others do
'R eprin ted with perm ission o f The Wall Street Journal, copyright 1 9 9 4 , Dow Jones &
Com pany, Inc. A ll rights reserved.
223
224
APPENDIX
B
not, and in stead use shapes or designs an d require knowledge o f
only sim p le, universal concepts (m an y /few , o p e n /c lo se d ,
u p /d o w n ).
4. T he sp read o f people along the I Q continuum , from low to
high, can be represented well by the bell curve (in statistical jar­
gon, the “ n orm al curve” ). M o st people cluster around the aver­
age ( I Q 1 0 0 ). Few are either very bright o r very dull: A b o u t 3 %
o f A m ericans score above I Q 130 (often considered the thresh­
old for “gifted n ess” ), w ith about the sam e percentage below IQ
70 (IQ 7 0 —7 5 often being considered the threshold fo r m ental
retardation).
5. Intelligence tests are n o t culturally b ia se d against Am erican
blacks or oth er native-born, English-speaking peoples in the
U S. R ather, I Q scores predict equally accurately for all such
Americans, regardless o f race and social class. Individuals who
do not understand English well can be given either a nonverbal
test or one in their native language.
6. T h e brain processes underlying intelligence are still little
understood. Current research looks, for example, at speed o f
neural transm ission, glu cose (energy) uptake, and electrical
activity o f the brain.
G roup D ifferences
7. M em bers o f all racial-ethnic groups can be found at every I Q
level. T h e bell curves o f different groups overlap considerably;
but groups often differ in where their m em bers tend to cluster
along the I Q line. T h e bell curves for so m e groups (Jew s and
East A sian s) are centered somewhat h igher than for whites in
general. O th e r groups (blacks and H isp a n ics) are centered
somewhat lower than non-H ispanic whites.
8. T he bell curve for w hites is centered roughly around I Q 100;
the bell curve for A m erican blacks roughly around 8 5 ; and
those for different su bgrou p s o f H isp an ics roughly midway
between th o se for whites an d blacks. T h e evidence is less defin­
APPEN D IX
B
itive for exactly where above I Q 1 0 0 the bell curves for Jews and
A sians are centered.
Practical Im portance
9. I Q is strongly related, probably more so than any other sin­
gle measurable human trait, to many im portant educational,
occupational, econom ic, and social outcom es. Its relation to the
welfare and perform ance o f individuals is very strong in some
arenas in life (education, m ilitary training), m oderate but robust
in others (so cial competence), an d m odest bu t consistent in
others (law -abidingness). W hatever I Q tests measure, it is o f
great practical and social im portance.
10. A high I Q is an advantage in life because virtually all activ­
ities require som e reasoning and decision-m aking. Conversely, a
low I Q is often a disadvantage, especially in disorganized envi­
ronm ents. O f course, a high I Q no more guarantees success
than a low I Q guarantees failure in life. There are many excep­
tions, but the o d d s for success in our society greatly favor indi­
viduals with higher IQ s.
1 1 . T h e practical advantages o f having a higher I Q increase as
life settings becom e more com plex (novel, am biguous, changing,
unpredictable, or multifaceted). F o r example, a high I Q is gen­
erally necessary to perform well in highly com plex or fluid jobs
(the professions, management); it is a considerable advantage in
moderately com plex jobs (crafts, clerical and police work); but it
provides less advantage in settings that require only routine deci­
sion making or sim ple problem solving (unskilled work).
12. Differences in intelligence certainly are n ot the only factor
affecting perform ance in education, training, and highly com ­
plex jobs (no one claims they are), but intelligence is often the
m o st im portant. W hen individuals have already been selected
fo r high (or low ) intelligence an d so do not differ as much in
I Q , as in graduate school (o r special education), other influ­
ences on perform ance loom larger in com parison.
225
226
APPENDIX
B
13. C ertain personality traits, special talents, aptitudes, physical
capabilities, experience, and the like are im portant (som etim es
essential) for successful perform ance in many jobs, bu t they
have narrower (o r unknown) applicability or “transferability”
across tasks and settings com pared with general intelligence.
S om e scholars choose to refer to these other human traits as
other “ Intelligences.”
Source and Stability o f W ithin-Group D ifferences
14. Individuals differ in intelligence due to differences in both
their environments and genetic heritage. H eritability estimates
range from 0 .4 to 0 .8 (on a scale fro m 0 to I), m ost thereby
indicating that genetics plays a bigger role than does environ­
m en t
in
creating
IQ
differen ces
am ong
individuals.
(H eritab ility is the squared correlation o f phenotype with
genotype.) I f all environments were to becom e equal for every­
one, heritability w ould rise to 1 0 0 % because all remaining dif­
ferences in I Q w ould necessarily be genetic in origin.
15. M em bers o f the same family also tend to differ substan­
tially in intelligence (by an average o f abo u t 12 I Q p oin ts) for
b oth genetic and environmental reasons. T h ey differ genetically
because biological brothers and sisters share exactly h a lf their
genes with each parent and, on the average, only h alf with each
other. T h ey also differ in I Q because they experience different
environments within the same family.
16. T h a t I Q may be highly heritable does n ot mean that it is not
affected by the environment. Individuals are not born with
fixed, unchangeable levels o f intelligence (no one claim s they
are). IQ s do gradually stabilize during childhood, however, and
generally change little thereafter.
17. A lthough the environment is im p ortan t in creating I Q dif­
ferences, we do n ot know yet how to m anipulate it to raise low
IQ s permanently. W hether recent attem pts show prom ise is still
a m atter o f considerable scientific debate.
18. Genetically caused differences are n ot necessarily irrem edi­
APPENDIX
B
able (consider diabetes, p o o r vision, and phenylketonuria), n or
are environmentally caused ones necessarily remediable (c o n ­
sider injuries, poisons, severe neglect, and som e diseases). Both
may be preventable to som e extent.
Source and Stability o f Between-Group D ifferences
19. T h ere is no persuasive evidence that the I Q bell curves for
different racial-ethnic g rou p s are converging. Surveys in som e
years show that gaps in academ ic achievement have narrowed a
bit for som e races, ages, sch ool subjects and skill levels, but this
picture seem s too m ixed to reflect a general shift in I Q levels
themselves.
20. R acial-ethnic differences in IQ bell curves are essentially the
same when youngsters leave high school as when they enter first
grade. However, because bright youngsters learn faster than
slow learners, these sam e I Q differences lead to growing d is­
parities in amount learned as youngsters progress from grades
one to 12. As large national surveys continue to show, black 17year-olds perform , on the average, more like white 13-year-olds
in reading, math, and science, with H isp an ics in between.
21. T h e reasons that blacks differ am ong themselves in intelli­
gence appears to be basically the same as those for why whites
(or A sians or H isp an ics) differ among themselves. Both envi­
ronment and genetic heredity are involved.
22. T h ere is no definitive answer to why I Q bell curves differ
across racial-ethnic grou p s. T h e reasons for these IQ differences
between groups may be markedly different from the reasons
why individuals differ am on g themselves within any particular
group (whites or blacks or Asians). In fact, it is w rong to
assume, as many do, th at the reason why som e individuals in a
population have high I Q s but others have low IQ s m ust be the
same reason why som e populations contain m ore such high (o r
low) I Q individuals than others. M ost experts believe that envi­
ronment is im portant in pushing the bell curves apart, bu t that
227
228
APPE N D IX
B
genetics could be involved too.
23 . R acial-ethnic differences are somewhat sm aller but still su b ­
stantial for individuals from the same socioeconom ic back­
grounds. T o illustrate, black students from prosperous fam ilies
tend to score higher in I Q than blacks from p o o r families, but
they score no higher, on average, than whites from poor fam i­
lies.
2 4 . A lm ost all Americans w ho identify them selves as black have
white ancestors— the white admixture is abo u t 2 0 % , on aver­
age— and m any self-designated whites, H ispan ics, and others
likewise have m ixed ancestry. Because research on intelligence
relies on self-classification into distinct racial categories, as does
m ost other social-science research, its findings likewise relate to
some unclear mixture o f social and b iological distinctions
among grou p s (n o one claim s otherwise).
Implications for Social Policy
25. T h e research findings neither dictate nor preclude any par­
ticular social policy, because they can never determ ine our goals.
T hey can, however, help us estim ate the likely success and side
effects o f pursuing those goals via different m eans.
T h e following professors— all experts in intelligence and allied fields—
have signed this statement:
Richard D. Arvey, University of Minnesota
T hom as J. Bouchard, Jr., University of Minnesota
John B. C arroll, University of North Carolina at Chapel Hill
Raym ond B. Cattell, University of Hawaii
David B. C oh en , University of Texas at Austin
R en e V D aw is, University of Minnesota
D ouglas K . Detterm an, Case Western Reserve University
M arvin D unnette, University of Minnesota
H ans Eysenck, University of London
Jack Feldm an, Georgia Institute of Technology
A PP E N D IX
B
Edwin A. Fleishm an, George Mason University
Grover C. Gilm ore, Case Western Reserve University
R obert A. G ordon, Johns Hopkins University
Lin da S. G ottfredson, University of Delaware
R obert L. Greene, Case Western Reserve University
R ichard J. H aier, University of California at Irvine
G arrett H ardin, University of California at Santa Barbara
R obert H ogan , University of Tulsa
Joseph M . H o rn , University of Texas at Austin
Lloyd G. H um phreys, University of Illinois at Urbana-Champaign
John E. H unter, Michigan State University
Seym our Wi Itzkoff, Smith College
D ouglas N . Jackson, University of Western Ontario
Jam es J. Jenkins, University of South Tlorida
A rthur R . Jensen, University of California at Berkeley
Alan S. Kaufm an, University of Alabama
N adeen L. Kaufm an, California School of Professional Psychology
at San Diego
Tim othy Z . Keith, Alfred University
N adin e Lam bert, University of California at Berkeley
John C. Loehlin, University of Texas at Austin
D avid Lubinski, Iowa State University
D avid T. Lykken, University of Minnesota
R ichard Lynn, University of Ulster at Coleraine
Paul E. M eehl, University of Georgia
R . Travis O sborn e, University of Georgia
R obert Perloff, University of Pittsburgh
R obert Plom in, Institute of Psychiatry, London
Cecil R . R eynolds, Texas A &r M University
D avid C. Rowe, University of Arizona
J. Philippe R ushton, University of Western Ontario
Vincent Sarich, University of California at Berkeley
Sandra Scarr, University of Virginia
Frank L. Schm idt, University of Iowa
Lyle F Schoenfeldt, Texas A C M University
229
230
APPE N D IX
B
Jam es C . Scharf, George Washington University
H erm an S p itz , former Director of Research at the E. R. Johnstone
Training and Research Center, Bordentown, N .J.
Julian C. Stanley, Johns Hopkins University
D e lT h iessen , University of Texas at Austin
Lee A. T h o m p so n , Case Western Reserve University
R obert M . T horndike, Western Washington University
Philip A nthony Vernon, University of Western Ontario
Lee W illerm an, University of Texas at Austin
INDEX
6 0 Minutes, 149, 167
Agreeableness, 57
Alleles, 8 9 - 9 2
AA A, See American Anthropological
Association
AA A S, See American Association for the
Advancement o f Science
Abecedarian Project, 133
Abilities o f man, the: Their nature and measurement,
(Spearman), 66, 137
Abilities, 49
A B O blood group, 119
Abstractness, levels of, 4 8
Adapted mind, the (Cosm ides, Tooby, and
Barkow), 67
Additivity, 75
A dopted children, and heritability o f IQ , 73
A dopted children, IQ s correlations of, 3
A E P s, See Average evoked potentials
A E R A , See American Educational Research
Association
Affirmative Action, 172, 1 7 5 -1 7 8 , 182, 1 9 0
Alomar, R oberto, 69
Alomar, Sandy, Jr., 69
Alsop, Joseph, 149, 167
Alsop, Joseph, 189
American Anthropological Association,
Statem ent on Race, 4, 1 10, 1 4 4
Jensens criticism s of, 4, 1 10—111,
118—1 1 9
American A ssociation for the Advancement o f
Science, 19, 45
American Educational Research Association,
36
American Psychological Association, 5, 2 1 —22,
79, 1 1 2 , 1 4 2 -1 4 4 , 149, 1 5 8 , 163, 170
1957 Bingham Award Lecture by S ir Cyril
Burt, 2 1 —2 2
report on The Bell Curve and race—I Q ques­
tion, 1 1 2
Tests and Measurements Division of, 79
African (race or population cluster), 120—123
American Psychologist, 106, 145, 161, 179
African Americans, degree o f European ances­
American Sociological Association, 8 4
try of, 126
“Aggression in Fantasy and Overt Behavior,”
Jensens doctoral dissertation at
Columbia University, 11
American Y outh Symphony, Jensens audition
for, 9
Amerind and E skim o (race or popu lation clus­
ter), 12 1 —124
231
232
INDEX
Analysis o f variance, 75
BGA, See Behavior Genetics Association
Analytical Intelligence, 3, 4 6 , 57. See also
Bhavagad Gita, Jensens admiration of, 1 8 7
Sternberg, R obert J., Triarchic theory o f
intelligence
Bias in Mental Testing (Jensen), 83, 114, 128,
145, 1 5 9 , 1 6 4 -1 6 5
APA, See American Psychological Association
“Big Five” personality factors, 57, 6 3 , 6 7
APA, See American Psychological Association
Biological environment and IQ , 7 0
Aphasia, 60
Biological environment, and g, 85
Arctic Asian (race or population cluster),
Biology of the race problem, the (W. C. G eorge),
1 2 0 -1 2 3
Arithmetic reasoning, 5 2 —53
Arm ed Services V ocation Aptitude Battery
(ASVAB), 182
ASVAB, See Armed Services Vocation Aptitude
Battery
Average deviation from the mean, 75
Average evoked potentials, an & g, 5, 47, 139
20-21
“ Black English” versus standard E nglish theory
o f Black—W hite difference in average
IQ , 1 2 9 - 1 3 0
Jensens criticism s of, 129—130
Black power movement, 13
Black—W hite difference in average I Q , 4, 17,
20, 2 3 , 3 2 , 1 2 6 -1 4 4 , 1 3 7 -1 4 0 ,
1 7 2 - 1 7 3 , 1 7 9 -1 8 0 , 1 8 7 -1 8 8
Bach family, 69
Bach, Johann Sebastian, 69
Bardeen, John, 148
Barkow, Jerome, 67
genetic factor in, 187—188
Bodily—kinesthetic intelligence, 4 7, 5 6 . See also
Gardner, Howard, Multiple intelligences
Bolyai family, 69
Barrymore family, 69
Bonds, Barry, 69
Bean, Robert Bennett, 2 0 —21
Bouchard, T h o m as, 101, 141
Beethoven, Ludwig van, 59
Brain damage, and multiple intelligences, 46
Behavior Genetics Association, 5, 79, 88, 148,
Brain drains and brain gains, 173
155, 162. See also “ Survey o f Expert
Brain glucose m etabolism, and g, 4 7 , 6 3 —65
Opinion on Intelligence and Aptitude
Brain size, 6 3—6 5 , 135, 137
Tests”
Brain waves, See Average evoked potentials
Behavior Genetics, 14, 101
Brand, Christopher, 164—165
Behavioral and Brain Sciences, 14, 158
Brattain, W illiam , 148
“ Behavioral differences between
British journal o f psychology, the, 1 0 1
Chinese—American and
Broca, Paul, 2 0
European—Am erican newborns”
Brody, N athan, 141
(Freedman and Freedman), 145
Burt affair, the (Joynson), 107
Behavioral Genetics (Plom in, et al.), 106
Burt Affair, 4 , 19, 2 2, 43, 9 9 -1 0 1
Behavioral genetics, 6 1
Burt, Sir Cyril, 4, 19, 43, 74, 1 0 6 - 1 0 7
Behaviorism, 10
allegations against, See Burt Affair
Bell curve, the (H errnstein and Murray) 5, 67,
Bingham Lecture, “The Inheritance o f
106, 141, 145, 1 6 3 - 1 6 6
American Psychological Association report
on, I 4 I - I 4 2 , 161
M ental Ability,” 21
Jensens defense of, 99—103
Bush, George H . W., 3, 27
Bell Curve Wars, 5, 126, 1 4 7 - 1 7 0
Berkeley (CA ) School D istrict, and Jensenism,
3 7 -3 8
Bernoulli family, 69
Capone, Al, 5 8
Carnegie Foundation, 152
Carroll, John B., 5 7, 67
233
INDEX
Casanova, 58
Creating M inds (Gardner), 67
“ Case o f Cyril Burt, the” (Jensen), 107
Creative Intelligence, 3, 46, 56—5 7 . See also
Caucasoid (race or population cluster),
1 2 0 -1 2 3
Cavalli—Sforza, L. L., criticisms o f race con­
Sternberg, Robert J., Triarchic theory o f
intelligence
“Criminal intelligence,” 58
cept and research on genetic distance and
Cronbach, Lee, 18, 30
population clusters, 119—123
Cuba, as center for biotechnology, 185
Cavalli—Sforza, F., 145
Cultural bias in mental tests, 1 1 4
China, population control program of, 184
Culturally disadvantaged, 171
Chinese, average IQ as evidence against
Culture—only hypotheses o f race differences in
discrimination theory o f race differences
in IQ , 131
IQ , I I I —112, 188
Jensens criticisms of, 127—13 3
Cicourel, Aaron, 18
C yril Burt: fr a u d orframed .^M ackintosh), 107
“ Citizens groups” in Southern states, Jensens
C yril Burt: psychologist (H earnshaw ), 107
reaction to requests from supporting
segregation, 21
Civil Rights movement, 33
Classical music, Jensens early interest in, 9
Coleman report on school achievement,
171—172, 175
Colum bia University, 2 2 —23
Commentary, 170
Com pensatory education, failure of, ix, 18, 20,
Darwin, Charles, 43, 151
“ Debunking Scientific Fossils and Straw
Persons” (Jensen), 156
Declaration o f Independence, 147, 149
Deductive reasoning, 52—53
Default H ypothesis o f Black—W h ite difference
in average IQ , 4, I I I , 126, 132-137,
141, 188
40, 171, 187—188. See also Abecedarian
Dempster, Everett, 147, 155
Project, Milwaukee Project
Depth psychology, 10—I I
Concept form ation, 4 8
Detterman, Douglas K., I, 6, 4 8 , 66
Conditioning, 4 8
Deutsch, M artin, criticisms o f Jensen, 34—35
Conscientiousness, 57
Consensus, meaning o f in science, 167
Jensens response to, 3 4 —35
Devi, Shakuntala, 59
Cooley, Charles, 84
Deviations from the mean, 75
Core culture theory o f Black—W hite difference
Discovery o f India, The (J. N eh ru ), 2 7
in average IQ , 128—129
Correlated vectors, method of, 63
“ Correlation between Relatives on the
Supposition o f Mendelian Inheritance”
(Fisher), 93
Discrim ination theory o f race differences in
IQ , 13 0 -1 3 1
Jensens criticisms of, 130—131
Division 5, See Test and M easurem ent o f the
American Psychological Association
Correlation coefficient, 44, 50
Dizygotic twins, 93—95, 98
Corsini encyclopedia of intelligence, The, 7, 8, 15
D N A markers and race differences, 134
Cosm ides, Leda, 47, 67
Donahue, Phil, 189
Craighead, W. E., 15
Cranial capacity, average race differences in,
D ouglas, Stephen, 150
135
D uffy blood group, 125
Dum as, Alexandre, 69
Cranial capacity, correlation with IQ , 135
Dynam ic psychology, 10
Cranial measurements, effects o f climate in
Dysgenics, arguments against evidence of, 173,
selecting for, 121, 122
1 8 0 -1 8 4
234
IN D E X
example o f in sizing garments, 55—5 6
e2, See environmentality
East A sians, average brain size and intelligence
of, 1 36
E ast Indians, average IQ o f as evidence against
use outside o f psychometrics, 52—53
Factor structure o f mental tests in Blacks and
Whites, 129
Family environment and IQ , 39—40
discrimination theory o f race differences
Fischer, Bobby, 58
in I Q , 131
Fisher, Sir Ronald A., 7 1, 8 7 -8 9 , 9 3 - 9 5 , 107
Eastern Psychological A ssociation, 101
Five factor model o f personality, the (W iggins), 67
Edinburgh University, 163
Fletcher, R „ 107
Edson, Lee, 36, 149, 166—1 6 7
Flynn effect, 1 4 0 - 1 4 1
Educational Testing Service ( E T S ) , 5, 149,
Forbes, 166
1 6 3 - 1 6 4 , 185
Spearm an Symposium, 1 6 3 —1 6 4
Ehrlichman, John, 36, 151, 1 6 9
Einstein, Albert, 46
Emergenesis, 30
Emperor’s new clothes: Biological theories o f race at the
millennium (Graves), x, 17 0
Encyclopedia o f intelligence, the (Sternberg), 14,
6 6 - 6 7 , 141
Encyclopedia o f psychology, the 14
F ord Foundation, 1 5 2
Fortune, 149
“ Foundation for fascism : T h e new eugenics
movement in the U nited States”
(Mehler), 17 0
Frames o f mind (G ardner), 67
Fraser’s Magazine, 15
Free speech movement, 31—32
Freedman, Daniel, studies o f race differences
in infant behavior, 134
Environmentality (e2), 76—78
Freedman, N. C. 1 3 4
Equal O pportunity, 172, 17 5 —1 7 8
Freud, Sigmund, 10
Erikson, Erik, 37
Erlenmeyer—Kimling, N ikki, 2 2
E T S, See Educational Testing Service
Eugenics, 8 1 —83, 173, 186
g (general mental ability), 3, 5, 40, 4 3 —67,
156, 163
and brain—wave patterns, 5
negative, 183
and educational reform , 190
positive, 183
and family environment, 39—40
European Americans, degree o f African ances­
try of, 126
Evolutionary psychology, 4 7 , 5 9 , 61, 67
and Flynn effect, 141
and glucose m etabolism in the brain, 5,
140
Evolutionary theory, and race differences, 112,
134
and inbreeding depression, 5, 139
Existential intelligence, 47, 5 6 . See also Gardner,
and Jensen’s D efau lt Hypothesis o f
H oward, Multiple intelligences
Extraversión, 5 7
and social complexity, 1 8 6 -1 8 7
Eysenck, H an s J„ 11—12, 19, 2 6 —2 7 , 107,
1 55, 1 70
influence o f Jensen and Jensenism , 11—12,
19
and B u rt affair, 107
and heterosis, 139
Black-W hite differences in, 126—127
and wealth o f nations, 183—184
as predictor o f learning, 65
as predictor o f welfare dependence,
182-183
average Black—W h ite differences in, 136
average evoked potential correlates of, 139
Factors, 4 4 , 4 9
biological evidence for, 63
Factor analysis, 49, 5 0 -5 6 , 6 3 , 6 7 , 156
biological reality of, 4 7
235
INDEX
brain glucose metabolic rate (G M R ) corre­
lates of, 1 40
Genetic additivity, 89—92
Genetic bottlenecks, 134
compared with physical g (gravitation),
Genetic counseling, 183, 185
5 0 -5 1
correlation with biological variables, 4 7
Genetic distance, 117, 120—123
correlation with brain glucose m etabolism ,
Genetic drift, 115
47
Genetic dominance, 89, 91
Genetic engineering, 173
correlation with brain size, 47
Genetic polymorphisms, 119
correlation with brain waves, 4 7
Genetics and education (Arthur R. Jensen), 15, 30,
correlation with heritability estimates, 4 7
41
correlation with inbreeding depression, 4 7
Genotype—by—environment covariation, 84
effects o f biological environment on, 4 0
Genotypes, 8 9 —90
evidence for from correlation matrices, 49
Gentlemen’s quarterly, 170
G oulds criticism of, 45, 51
Geography o f human genes, the (Cavalli—Sforza,
heritability of, 4 7 , 8 8 —102, 138—139,
1 8 7 -1 8 8
not an interval scale, 64
physiological correlates of, 139
M enozzi, and Piazza), 11 9 —122, 145
George, W. C., 2 0 -2 1
Getting Here: The Story of Human Evolution
(H ow ells), 1 2 0 -1 2 3
race differences in, 111
Gillham, N .W ., 190
statistical evidence for, 4 3 -4 5 , 4 7
G M R , See brain glucose metabolic rate
Sternberg s argument against, 45
Gottfredson, Linda, 170
threshold aspect of, 58
Gould, Stephen Jay, criticisms o f Jensen and
gfactor, the: the science o f mental ability, (A rthur R.
Jensen), 39, 67, 106, 122, 144, 155
difficulty in publishing, 164
g factor, the (Brand), 1 64—165
g factor in the design o f education” (Jensen),
190
g loadings, and average Black—W hite differ­
Jensenism, x, I, 6, 45, 5 1, 6 7 , 135,
1 5 5 - 1 5 6 , 170
Graves, Joseph L., 170
Great human diasporas, the: the history o f diversity and
evolution (Cavalli—Sforza and
Cavalli—Sforza), 119, 145
Great Society programs, 17, 3 3 —3 5 , 7 0
ences, 137—140. See also Spearm ans
Griffey, Ken, Jr., 69
hypothesis
Grigorenko, Elena, 106
Galton Library, 2
Group Factors, 5 2—53, 56
Galton, Sir Francis, 15, 43, 50, 59, 64—6 6
Guggenheim Foundation, 152
and mental chronometry, 189
and terms “ nature” and “nurture,” 15
h2 — See heritability
biography of, 1 90
H abit reversal, 4 8
characteristics o f genius, 30
Halpern, Diane, 141
coins term “eugenics,” 82
Harlow, H arry, 21
develops twin method, 15
H arvard educational review, the (H ER), and
Gandhi, M ohandas, 14, 2 7 —28, 37, 4 6, 187
Jensenism, 13, 15, 18—19, 3 2 , 4 1 , 74,
Gardner, Howard, x, 3, 4 6 -4 7 , 61, 67
106, 109, 147, 154, 161, 166, 171,
Garner, W. R., 145
1 7 3 -1 7 4
Garrett, Henry E., 19, 2 2 —24
Head Start program, 33
Gehrig, Lou, 69
Hearnshaw, Leslie, 101, 106
General mental ability, See g
Height, heritability of, 85—86
236
INDEX
H E R , See Harvard Educational Review
H eritability (h2) , 3, 7 0 - 8 8 , 6 9 - 1 0 7
broad, 84
in Black population, 1 0 5 —106
narrow, 84
o f * 47, 8 8 -1 0 2 , 1 8 7 - 1 8 8
H errnstein, Richard J., 67, 106
Institute o f H um an Learning (University o f
California at Berkeley), 12, 19
Institute o f Personality Assessment and
Research, 59
Institute o f Psychiatry at University o f
London, I I , 103
Intelligence, 4 3 —67. See g, IQ
Hersen, M., 107
difficulty in defining, 43, 47—49, 66
H eterosis, and g factor, 139
genetic basis of, See also g, Heritability
Heterozygous, 90
Intelligence, I, 6, 14, 170
H irsch, Jerry, 8 7 -8 8 , 1 4 7 —148
“ Intelligence and lifelong learning”
criticisms o f Jensen and Pioneer Fund, 155
H istorical experience theory o f Black-W hite
in average IQ , 1 3 0 —131
Jensens criticisms of, 1 3 0 —131
H offm an , Dustin, 46, 5 8
Hom ozygous, 90—9 2
H orow itz, Vladimir, 6 4
“ H ow much can we boost I Q and school
(Sternberg), 106
“ Intelligence, behavior genetics, and the
Pioneer F u n d ” (Weyher), 170
Intelligence; heredity, and environment (Sternberg and
Grigorenko), 106
Intelligence; instruction, and assessment (Sternberg
and W illiam s), 190
Intelligence: A new look (Eysenck), 156, 170
achievement,” (Jensen), ix, 13, 18—19,
Interaction effects, 8 4
2 1 , 106. See also Jensen, Arthur R., and
Interaction o f factors theory o f race differ­
H arvard educational review
D eutschs criticisms of, 34—35
Howells, William W., 1 21—123
H um an cognitive abilities: A survey o f factor—analytic
studies (Carroll), 6 7
ences in I Q , 131
Jensens criticism s of, 131
Interpersonal intelligence, 47, 56. See also
Gardner, H oward, Multiple intelligences
IQ , 43—67. See also g, Intelligence
H um an Genome Project, 103, 125—126
average Black—W hite difference in, 17
Humphreys, Lloyd, 1 62
average difference between siblings , 13 7
H unt, Earl, 106
failure o f attem pts to raise, 20
H unt, M orton, 149, 1 6 7
heritability of, 86
H untingtons chorea, 8 2
specific genes for, 103—104, 125
H ybrid vigor, See H eterosis
I Q controversy, the: the media and public policy
(Snyderman and Rothman), 40, 79—8 0,
Identical twins, See M onozygotic twins
Immigration, 173
Inbreeding depression, 4 7 , 6 3, 139
Inductive reasoning, 5 2 —53
Infant behavior, race differences in, 134
106, 166, 170
IQ : A triarchic theory o f human intelligence
(Sternberg), 67
Item-to-item correlations o f mental tests for
Blacks and W hites, 129
Inference, 48
“ Inheritance o f mental ability, the” (APA
1957 Bingham Award Lecture by Sir
Cyril Burt), 2 1 —2 2
Institute for Advance Study in the Behavioral
James, William, 2 5, 8 0 —81
Japan /N ortheast Asian (race or population
cluster), 121—123
Japanese, average I Q o f as evidence against dis­
Sciences, Stanford, Jensens fellowship at,
crimination theory o f race differences in
12
IQ , 131
237
INDEX
Jarvik, Lissy, 2 2
Jefferson, Thom as, 147, 150
Jensen, Arthur R.
account o f Jensenism, 15
account o f origin, reaction to, and contro­
versy over Jensenism, 41
admiration for and influence by M . Gandhi,
14, 2 7 - 2 8
admiration for Bhagavad Gita, 187
admiration for particular interviewers,
167
analysis o f Roychoudhury and Nei data on
racial classifications, 1 2 0 -1 2 2
and Cavalli-Sforza studies o f population
clusters
and double standard regarding Jensenism,
1 5 7 -1 5 8
and politics, 14
and Shockley and Pioneer Fund, 154—155
arguments against Sternberg’s Triarchic the­
ory o f intelligence and g, 56—57
arguments against theory o f multiple intel­
ligences and for^ , 56—59
as second clarinetist with San Diego
Symphony, 9
current opinion on limitations o f I Q tests,
1 8 8 -1 8 9
’’Debunking scientific fossils and straw per­
sons,” , 156
default hypothesis o f race differences in
IQ , 111—1 1 3 ,1 3 2 - 1 3 7
defense o f Burt, 7
defense o f Pioneer Fund, 152—15 5
difficulty in publishing The g facto r: The science
of mental ability, 164—165
family background of, 8
Gandhian philosophy o f and o p p osition to
racial segregation and discrim ination,
33 -3 4
initial belief in Great Society program s, 33
interest in and impressions o f “ people who
have m ade’ it,” 26—30
invited to give Spearman lecture at
Educational Testing Service Spearm an
Sym posium , 163—164
meeting and correspondence with Daniel
Patrick Moynihan, 36—38
member o f Behavior Genetics Association,
1 4 7 -1 4 8
on media treatment o f Jensenism,
B ias in Mental Testing (Jensen), 114, 159
1 6 7 -1 6 9
opinion o f critics and supporters, 1 4 —15
B ia s in Mental Testing, 12 8
opinions on Affirmative Action and Equal
audition for American Youth Symphony, 9
bibliography of, 1 91—2 2 7
Opportunity, 172, 175—178, 1 9 0
brief biography of, 8—15
opposition to racial segregation, 21
characterization by Cronbach as being filled
participation in University o f C aliforn ia at
with “missionary zeal,” 30
childhood hobbies of, 8—9
criticism o f arguments against evidence o f
dysgenics, 181
criticisms o f Culture—only theories o f
Berkeley symposium on Jensen and
Jensenism, 18
postdoctorate at London University, 2 2
question o f Jensens role in prom oting
Jensenism controversy, 30—3 2
Black—W hite I Q differences, 127—13 3
recipient o f government grants to programs
criticisms o f Milwaukee Project, 132—133
to help culturally disadvantaged students,
current opinion on failure o f compensatory
education, 187—188
current opinion on genetic factor in
Black-W hite difference in average I Q ,
1 8 7 -1 8 8
current opinion on heritability o f g factor,
1 8 7 -1 8 8
34
refusal o f requests from “C itizens groups”
in Southern states to support segrega­
tion, 21
rejects any comparison o f Jensenism with
N azi theories o f master race,
1 42-1 4 4
238
INDEX
rejects claim that H ER article gave N ixon
enters dictionaries, 13, 17
administration justification to slash
evidence o f support for among experts, 40
Great Society program s, 3 4 -3 5
Jensens claim o f double standard, 157—158
rejects claim that Jensenism is “fringe sci­
ence," 149, 156—1 5 7
rejects claims o f deeper, hidden motive
N ixons interest in, 3 6 -3 7
origin o f term , 36
“Jensenism: T h e bankruptcy o f ‘science’ with­
behind Jensenism, 3 2 —34
rejects H irschs criticism s o f Hirsch and
out scholarship” (Hirsch), 155
Jews, average I Q o f as evidence against dis­
Mehler, 1 5 4 -1 5 5
crim ination theory o f race differences in
response to G oulds The mismeasure of man, 156
Straight talk about mental tests, 170
IQ , 131
studies genetics with Dempster, 147—148
Johnson, Lyndon, Great Society program s, 13,
33
talks before PTA m eetings in favor o f H ead
Journal of Educational Psychology, The 4 8 , 6 6
Start programs, 3 3
Joynson. R . B „ 1 0 7
The g Factor: The science o f mental ability (Jensen),
144, 155
Kamin, Leon, 3 6 , 1 0 0 -1 0 1 , 1 0 6 - 1 0 7
views on dysgenics, 1 7 3 , 180—181
Katz, Irwin, 3 4
views on educational reform, 172,
Kinship correlations in IQ , 3 -4 , 9 3 —9 6 , 106,
1 7 6 -1 8 0 , 190
views on equality, 6 4 —6 6
138
Klineberg, O tto, 19, 2 2 -2 4
views on eugenics, 1 7 3 , 1 8 3 -1 8 4
views on genetic engineering, 173
Lane, Charles, 1 7 0
views on genetic screening and engineering,
1 8 4 -1 8 6
Language denotative, 48
Learning, 4 8
views on immigration, 173, 184—185
Learning set form ation, 48
views on population grow th and control,
Learning, transfer of, 48
173, 1 8 3 -1 8 4
views on relation between public policy and
science, 173—1 90
Lederberg, Joshua, 18
Letter series test, 5 2 —53
Libby, W illiam J., 3 1
views on welfare, 1 8 2 —183
Life, ix
vote by absentee ballot for Lyndon Johnson
Life of Sir Francis Calton, A (Gillham), 1 9 0
in 1964 election, 33
work on mental chronometry, 189
Limits of fam ily influence, The: Genes, experience, and
behavior (Row e), 39, 106
Jensen, Barbara (M rs. A rthur R.), 9
Lincoln, A braham , 147, 150
Jensenism, ix-x, 1 -2 , 5, 14, 1 7 -4 1 , 47, 126,
Lindzey, G., 1 4 5
1 4 7 -1 7 0 , 1 8 7 - 1 8 8 ,
and “ fringe science,” 149, 1 5 6 -1 5 7
and public policy, 1 7 1 —190
and Snyderman and Rothm an survey o f the
Linguistic intelligence, 46, 56. See also Gardner,
Howard, M ultiple intelligences
Linkage tree diagram s, 121
Loehlin, J„ 14 5
Behavior Genetics Association and Tests
Logical reasoning, 5 2 -5 3 , 56
and Measurement Division o f the
Logical-m athem atical intelligence (H ow ard
American Psychological Association,
149, 163
Gardner), 4 6 - 4 7 , 56. See also Gardner,
Howard, M ultiple Intelligences
controversy surrounding, 19—20
London School o f psychology, 63—64, 74, 190
current status of, 1 8 7 —18 8
Lynn, Richard, 1 7 0
239
INDEX
Mackintosh, N . ]., 107
M od u lar theory o f the m ind, 5 6, 67
Magnetic Resonance Imaging (M R J), studies
M on goloid (race or population cluster),
o f average race differences in brain size
and IQ , 1 3 5 - 1 3 6
“Mainstream science on intelligence,”
1 2 1 —123
M onozygotic twins, and heritability o f IQ ,
7 2 - 7 5 , 85, 9 3 -9 9
(G ottfredson), statement by 5 0 scientists
M orton , Newton, 101
in Wall Street Journal, 149, 163, 170,
M oynihan, Daniel Patrick, 3, 19, 36—38
2 2 9-236
M ozart, Amadeus and L eop old , 69
Signatories of, 2 3 4 —2 36
Malaria, 92
McClearn, Gerald, 80, 106
M ultiple intelligences, theory of, x, 3, 4 6 -4 7 ,
6 1 , 67. See also Gardner, Howard
Jensens arguments against and for g, 56—59
M ead, Margaret, 19, 2 3 —25, 75
Murray, Charles, 67, 106, 151
M e a n ,, 75
M usical intelligence, 47, 5 6 . See also Gardner,
Measurement error, 78
M edia, and Jensenism, 79
H oward, Multiple intelligences
M utations, 91—92
Mehler, Barry, 148
Criticisms o f Jensens Harvard Educational
Review article, 154
Criticisms o f Pioneer Fund, 15 4
M ellon Foundation, 152
Memories o f my life (G alton), 82
Memory, long-term , 48
Memory, short-term , 48
N ational Academy of Science report: Ability testing: uses,
consequences, and controversies (W igdor and
G arner), 83, 128, 145
N ation al Educational A ssociation, denuncia­
tion o f Jensens B ias in M ental Testing, 158
Native American (race or popu lation cluster),
1 20-1 2 3
Mendel, Gregor, 89
N atural selection, 9 1 -9 2 , 1 1 5
Mendelian algebra, 93
N aturalistic Intelligence (H ow ard Gardner),
Mendelian genetics, 8 9 —93
Mendelian inheritance, 119
4 7 , 56. See also Gardner, Howard,
M ultiple Intelligences
Mendelian traits, 9 2
Nature, 101, 145
M enozzi, P. 121, 145
Nature, Nurture, and Psychology (M cC learn and
M ental chronometry, 189
P lom in), 80, 106
M ental modules, 4 7 , 59—60
N E A , See National Educational Association
“ Mentality bunker, the” (Sedgwick), 1 7 0
N eg roid (race or population cluster),
Michelangelo, 59
Microenvironment effects, 97—98
1 2 1 —123
N ehru, Jawaharlal, 27
Miele, Frank, 6 7 , 106, 144, 1 8 9 - 1 9 0
N ei, M asatoshi, 120
Miller, Adam, 170
N eisser, Ulric, 141
Miller, D. J., 1 07
Milwaukee Project, 132—133
M innesota Transracial Adoption Study, and
race differences in IQ , 132—13 3
M innesota Twin Project, 101
Mismeasure of man, The (Gould), criticism s o f
et al., “ Intelligence: knowns and unknowns,”
1 45
N em eroff, C. B., 14
N euroticism , 57
N ew Guinean/Australian (race or population
cluster), 120-123
Jensenism, x, 6, 67, 135, 155—156, 162,
New Review o f Books, 83, 170
170
New York Review of Books, 83
Mithen, Stephen, 6 7
New York Times Magazine, ix, 13, 149, 166
240
IN D E X
Newsweek, i x , 166
N ew ton, Isaac, 59
N ixon administration, and Jensenism, 34
N ix o n ’s piano: Presidents and racial politics from
Washington to Clinton ( O ’Reilly), 169
Population clusters, as substitute term for race,
120-123
Population growth and control of, 173,
184-185
Practical Intelligence, 3, 4 6 , 56—57. See also
Nixon, Richard, 17, 33, 147, 151
Sternberg, R ob ert
N on —Europoid Caucasoid (race or population
cluster), 121—124
intelligence
N ortheast Asian (race or popu lation cluster),
12 0 -1 2 3
N utrition theory o f Black—W h ite difference in
average IQ , 127—133
Jensens agreement with, 1 2 7 —133
Triarchic theory o f
Predictive validity o f m ental tests for Blacks
and Whites, 1 2 9
Prehistory of the mind: the cognitive origins of art, reli­
gion, and science (M ith en ), 67
Principal Components Analysis (PCA), racial
classifications, 1 2 0 —122, 141
Principles of psychology (Jam es), 80-81
O ’Reilly, K., 169
Problem solving, 4 8
Openness, 5 7
“ Professors o f hate” (M iller), 170
O ut—o f—Africa theory o f hum an evolution,
Psychoanalysis, 10
1 34
O xford Review o f Education, The 19 0
Psychological Abstracts, 1 6 7
Psychological Reports, 1 7 0
Psychometrics, 43, 6 1 , 156
Pacific Islands and Southeast A sia (race or
population cluster), 1 2 1 —123
Paderewski, Ignacy (Jan), 8, 6 4
,
P T A , See Parents and Teachers Association
Public policy, Jensens view o f relation with
science, 173
Path analysis, and heritability estimates,
I0 I-I0 3
Quantitative genetics, 7 0 —78, 87 -8 8
Patterns o f Prejudice, 170
Quantitative Trait L oci ( Q T L ), 104
Patterson, John, 20—21
Question of Intelligence, A (Seligm an), 155, 17 0
Pearson, Karl, 50
Per—pupil expenditures, and school achieve­
ment, 171—172, 175
Perception, 4 8
R ace, 109-145
American Anthropological Association
statement on, 110, 118
Personality and Individual Differences, 1 4
as cultural construction, I I 0, 114—115
Phenotypes, 9 0
"fuzzy set” definition of, 110—I I I , 116,
Phenyketonuria (PK U ), 105
Piazza, A., 121, 145
Picasso, Pablo, 46
Pioneer Fund, 5, 147—149
Criticism s of, 152—155, 1 7 0
Jensen’s defense of, 152—155
“Pioneer Fund, the behavioral sciences, and the
118, 126
population genetic definition of, 1 10,
I 17—I 18
taxonomic definition of, 1 10, 115—117
R ace differences
and evolutionary theory, 112
culture—only H ypoth eses o f , I I I —112
media's false stories” (W eyher),
in anatomical traits, 13 4
170
in average brain size, 135
Playboy, 149
in average cranial capacity, 135
Plomin, Robert, 80, 1 0 3 - 1 0 4 , 106, 125
in biochemical characteristics, 134
Polygenic traits, 92—93
in D N A markers, 13 4
241
INDEX
in infant behavior, 125
Roychoudhury, A. K., 120
in physical traits, 134
Rushton, J. P. —Race, evolution, and behavior: A life
in physiological traits, 134
history perspective, 140, 144—145
Race differences in intelligence (Loehlin, Lindzey,
and Spuhler), 145
Race differences in intelligence, 2 0
San D iego Symphony, Jensens performance
with, 9
and average brain size, 20
San D iego Zoo, Jensens trading snakes with, 9
and Socioeconom ic Status (S E S ), 127—128
Sarich, V M ., on races as fuzzy sets, 145
compared to average sibling difference,
SAT, see Scholastic Aptitude Test
1 7 2 -1 7 3 , 180
Savants, 4 6, 58
culture—only theories of, 127—133
Scholastic Aptitude Test (S A T ), 185
Jensens Default Hypothesis of, I I I
School achievement, and per—pupil expendi­
Jensens studies of, 126—144
tures, 171—172, 175
School achievement, and pupil/teacher ratios ,
taboo against considering role o f genetic
factors in, 3 2
time needed to evolve, 1 3 4 -1 3 5
Race in North America: Origin and evolution o f a
worldview (Smedley), 144
Race Relations Abstracts, 170
Race, evolution, and behavior: A life history perspective
(Rushton), 144—145
“Race, IQ , and heredity” (Lane), 170
Races, 116
Racial medicine, 124
171—172, 175
School achievement, and teacher qualifications,
1 7 1 - 1 7 2 , 175
School achievement, failure o f attempts to
raise, 20
School facilities, and race differences in IQ ,
128
School facilities, as cause o f race differences in
IQ , 128
Jensens criticisms of, 128
Rain Man, 4 6 , 58
Science and politics of I Q , The (Kam in), 106—107
Range, 75
Rank order o f item difficulties o f mental tests
Science and public policy, 173
for Blacks and W hites, 129
Rao, C. R ., 101
Rather, Dan, 189
Science Citation Index, 167
Science, ideology, and the media (Fletcher), 107
Science o f human diversity: A history of the Pioneer
Fu nd (Lynn), 170
Ravens M atrices test, 5 2 -5 3 , 61
Seashore Measures o f M u sical Talents, 62
Reasoning, 4 8
Sedgwick, John, 170
Reductionism, in psychology, 10
Self-fulfilling prophecy theory o f race differ­
Reliability, o f mental tests for Blacks and
W hites, 1 2 8 -1 2 9
Researchfr a u d in the biomedical sciences (M iller and
H ersen), 107
ences in IQ , 131—1 3 2
Seligman, Daniel, 149, 1 5 5 , 167, 170
Sensory sensitivity, 48
SE S, See Socioeconomic factors
Ripken, Cal, Jr., 69
“Sexual intelligence,” 58
Rockefeller Foundation, 152
Shakespeare, William, and term s “ nature” and
Roosevelt, Theodore, and Black—W hite differ­
ences, 151
Rothman, Stanley ( The I Q controversy), 4 0 ,
7 9 - 8 0 , 149, 163, 166, 170
Rowe, David C. ( The Limits of fam ily influence),
39, 106
“ nurture,” 7, 15
Shermer, Michael, xi
Shockley, William, 148
and Jensen and Pioneer Fund, 154-155
Voluntary Sterilization Bonus Plan of, 148
Shuey, Audrey, 22—23
242
IND EX
Sickle anemia, 9 2
Straight talk about mental tests (Jensen), 67, 165, 170
Singapore, and eugenics, 183, 1 8 6
“Survey o f expert opinion on intelligence and
Skeptic, xi, 6 7 , 106, 144—145, 1 6 6
aptitude tests” (Snyderm an and
Skepticism, I
Rothman), 106, 149, 163, 170
Skinner, B. F„ 10
“ Sw iss Army Knife M o d e l o f the Mind,” as
Slavery, legacy o f and IQ , I I I
Smedley, Audrey R „ 144
analogy to M ental Modules, 47
Sym onds, Percival, I I , 2 5 —2 6
Smith, Adam , on ability and wealth o f nations,
1 8 3 - 1 8 4 , 186
“ Tainted sources o f The Bell Curve" (Lane), 170
Snyderman, M ark ( The I Q controversy), 40,
Tay—Sachs disease, 8 2
7 9 - 8 0 , 106, 149, 163, 1 6 6 , 170
Society for the Psychological Stu d y o f Social
Issues, T h e (SPSSI), criticism o f
Jensenism, 161—162
Socioeconom ic status, and race differences in
I Q , 7 0 , I I I , 1 2 7 -1 2 8 , 1 3 8
Southeast Asian (race or popu lation cluster),
1 2 0-123
17 1 -1 7 2 , 175
Tempest (William Shakespeare), and terms
“ nature” and “ nurture,” 7, 15
T est and Measurement o f the American
Psychological Association, 5,
Testing o f Negro intelligence, The, 22—23
Tests and Measurement Division (Division 5
Spatial intelligence, 47, 56. See also Gardner,
Howard, Multiple Intelligences
Spearman effect, 140
“Spearman’s g and the problem o f educational
equality” (Jensen), 190
Spearm ans hypothesis, o f Black—W h ite differ­
ences and
Teacher qualifications, and school achievement,
factor, 5, 112, 1 3 7 —140,
156, 1 64
Spearman, Charles 5, 4 3 -4 9 , 5 0 —5 1 , 64—66,
1 37
Spiritual intelligence, 47, 56. See also Gardner,
Howard, Multiple intelligences
SPSSI, T h e See Society for the Psychological
Study o f Social Issues
Spuhler, J., 145
Standard deviation, 75
Stern, C urt, 18
Sternberg, R obert J, 40, 5 6 - 5 7 , 6 6 —67, 106,
141, 190,
arguments against g factor an d fo r Triarchic
Theory, 4 5 - 4 6
o f the American Psychological
Association), 5, 161. See also “Survey o f
expert opinion on intelligence and apti­
tude tests”
Texas Adoption Project, 102
Them atic Apperception Test, 11
Thorndike, E. L. 25—2 6
T h ree—strata model o f abilities, 57
“ T o unfrock the charlatans” (Hirsch), 155, 170
Tooby, John, 47, 67
Toscanini, Arturo, 2 8 —2 9
Toward freedom (J. N eh ru ), 132
Triarchic Theory o f Intelligence, 45—46, 67
Jensens arguments against and for g factor,
5 6 -5 7
Tw in studies —as evidence for heritability o f
IQ , 138
Tw ins, and heritability o f IQ , 72
Twins, conjoined, 72
Twins, Galtons use of, 15
Twins, identical, 3
Triarchic theory o f intelligence, 4 0 , 4 5 -4 6
What is intelligence?, 48
U. S. New s & World Report, ix, 13, 30—32, 148
Stimulus discrimination, 48
U N E S C O Declaration o f Rights, 149
Stimulus generalization, 48
U n ited States Armed Forces, 18 1 -1 8 2
Stinchcombe, Arthur, 18
U n ited States C om m ission o f Civil Rights,
Stokowski, Leopold, 9
171, 175
243
INDEX
U nited States Constitution, 149
U nited States O ffice o f Education, grants to
Jensen, 3 4
Unrelated children reared together, I Q correla­
tion between, 4, 102
Wall Street Journal, The, statement by 5 0 scientists
on Mainstream Science on Intelligence,”
5 - 6 , 149, 163, 170, 2 2 9 - 2 3 6
Wallace, George, 2 0 -2 1 , 33
Wallace, M ike, 149, 167, 189
Wealth o f nations, The (Smith), 18 3 —1 8 4
Variance, 52, 7 0 - 7 8 , 83
Welfare, and g, 182
Verbal—educational skills and knowledge,
Welfare, Jensens views on, 182—183
5 2 -5 2 , 5 6
Vietnam War, 181
V isual perception, 52—53, 56
Völkischer Beobachter (N a z i Party newspaper), on
race and race differences, 143
Voluntary Sterilization Bonus Plan (Shockley),
148
Weyher, H arry F , defense o f Pioneer Fund, 170
What is intelligence? (Sternberg and Detterman),
4 8 , 66
W hite backlash, 19, 33
Wigdor, A. K „ 145
W iggins, J. S., 67
Williams, W. M „ 190
Witness to power (Ehrlichman), 169
Walker, Helen , 2 4
Woodworth, Robert, 25
Wall Street Journal, quotation o f M oynihan and
origin o f term, Jensenism, 36
Zubin, Joseph, 25
TELLIGENCE,
RACE, AND
GENETICS