Psyc 101
The Study of Intelligence
Francis Galton
First scientific theory
& measurement of
intelligence
Francis Galton
• Founder of EUGENICS movement (1883)
• Theory: Intelligence =
Strength of Nervous System
• Tests:
Battery of psycho-physical reactions
• Stats:
With C. Pearson developed
correlation coefficient
r = -1 to 0 to +1
Galton’s battery of tests
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Hand squeeze strength
Pain threshold
Reaction time
Breathing capacity
Head size
Judgment of 10 seconds
Memory tasks
etc.
Galton’s Laboratory
Galton’s form
for recording
psycho-physical
test results
James Cattell
Galton’s protégé
at Columbia
Found (with
Wissler) psychophysical tests did
not correlate highly
Alfred Binet
Alfred Binet
• Tried THEORY BASED test construction
(like Galton)
• Sub-tests:
memory
imagination
imagery
attention
comprehension
suggestability
aesthetic sentiment
moral sentiment
muscular strength
motor ability
Alfred Binet
• Sub-tests failed to inter-correlate
• Concluded intelligence complex &
multiple
• At gov’t request, created test for schools
• Turned to PREDICTION-BASED strategy
for constructing a test of intelligence
Binet testing a child
Theodore
Simon
Binet’s
collaborator
Sample
items from
Binet’s test
Binet Test
Mental Age
= 1 year for each “year” test passed
+ 1/5 year for each older sub-test passed
85% within 1 year of chron. age = “normal”
7% mental age 2+ years behind chron. age
& failing school
= “subnormal”
Binet test
Predicted school performance,
up to age 15 or 16
Identified:
– morons
“mildy retarded”
– imbeciles “moderately retarded”
– idiots
“profoundly retarded”
William Stern
Intelligence Quotient
=
Mental Age ÷ Chronological Age
( Terman later multiplied by 100 & redesigned
test to yield “bell curve” distribution without
calculation of “mental age.” )
Henry Goddard
translated Binet test
Eugenics advocate
Ellis Island testing
book on “Kallikaks”
Goddard and “Feeble-Minded Club”
Testing Immigrants at Ellis Island
Henry Goddard
“Our thesis is that the chief
determiner of human conduct is a unitary
mental process which we call intelligence;
[that] the intellectual or mental level for
each individual is determined by the kind
of chromosomes that come together with
the union of the germ cells; that it is but
little affected by any later influences…”
Henry Goddard
“The people who are doing the
drudgery are, as a rule, in their proper
places.”
Henry Goddard
“We must learn that there are great
groups of men, laborers, who are but little
above the child, who must be told what to
do and shown how to do it; and who, if we
would avoid disaster, must not be put into
positions where they will have to act upon
their own initiative or their own judgment.”
Henry Goddard
“Now the fact is, that workmen may
have a 10 year intelligence while you have
a 20. To demand for him such a home as
you enjoy is as absurd as it would be to
insist that every laborer should receive a
graduate fellowship. How can there be
such a thing as social equality with this
wide range of mental capacity?”
Henry Goddard
“Democracy means that the people
rule by selecting the wisest, most
intelligent and most human to tell them
what to do to be happy. Thus Democracy
is a method for arriving at a truly
benevolent aristocracy.”
The Kallikak Family:
A Study in Feeble-Mindedness
Henry Goddard
1912
Deborah Kallikak at the Training School
Normal & “Degenerate” Descent Lines
“There can be no doubt that the
photographs of the Kallikak family
members have been retouched…
this retouching was limited to the
facial features – specifically eyes,
eyebrows, mouths, nose and hair.”
-- Smithsonian Analysis
Director of Photographic Services, Smithsonian Inst.
“The harshness clearly gives the
appearance of dark, staring features,
sometimes evilness, and sometimes
mental retardation. It would be
difficult to understand why any of this
retouching was done were it not to
give the viewer a false impression of
the characteristics of those
depicted.”
-- Smithsonian Analysis
Lewis Terman
Created Stanford-Binet
Changed scoring:
mental / chron X 100;
100 = average for age
Began “Terman Study”
Eugenics advocate
Lewis Terman
“Defectives” should be
segregated, which “will ultimately
result in curtailing the reproduction
of feeble-mindedness and in the
elimination of an enormous amount
of crime, pauperism, and industrial
inefficiency.”
Lewis Terman
“Not all criminals are feebleminded, but all feeble-minded
persons are at least potential
criminals. That every feeble-minded
woman is a potential prostitute would
hardly be disputed by anyone.”
Lewis Terman
“Moral judgment, like business
judgment, social judgment, or any
other kind of higher thought process,
is a function of intelligence. Morality
cannot flower and fruit if intelligence
remains infantile.”
Lewis Terman
“The common opinion that the child
from a cultured home does better in
tests solely by reason of his superior
home advantages is an entirely
gratuitous assumption… The children
of successful and cultured parents test
higher than children from wretched and
ignorant homes for the simple reason
that their heredity is better.”
Lewis Terman
Women tested to have IQs equal to
men, but he opposed allowing them
access to professions:
Women with IQs between 100
and 120 should get jobs as teachers
or “high-grade stenographers” and
paid at level of men with IQs of 85.
Lewis Terman
“Among laboring men and servant
girls there are thousands like them
[borderline feebleminded, with IQs =
70 – 80]… The tests have told the
truth… No amount of school
instruction will ever make them
intelligent voters or capable citizens…
Lewis Terman
“They represent the level of
intelligence which is very common
among Spanish-Indian and Mexican
families of the Southwest and also
among Negroes….
Their dullness seems to be racial,
or at least inherent in the family stocks
from which they came… ”
Lewis Terman
“There is no possibility at
present of convincing society that
they should not be allowed to
reproduce, although from a eugenic
point of view they constitute a grave
problem because of their unusually
prolific breeding.”
Robert Yerkes
Pioneer primate
researcher
APA President
Head of WWI IQ testing
committee
Eugenics advocate
Army Alpha
sample
questions
Army Alpha
sample problems
Army Alpha Items
• Washington is to Adams as first is to…
• Crisco is a: patent medicine, disinfectant,
toothpaste, food product
• The number of a Kaffir’s legs is: 2, 4, 6, 8
• Christy Mathewson is famous as a: writer,
artist, baseball player, comedian
Army Beta
sample problems
Army IQ Testing Major Findings
• Average mental age of white
American adult men: 13
• 37% of white American adult
men are “morons”
Army Alpha results by race
Army beta results by race
A Study of American Intelligence
Carl C. Brigham
1923
A Study of American Intelligence
Robert Yerkes
1923
Army tests free of cultural bias:
“These group examinations were
originally intended, and are now definitely
known, to measure native intellectual
ability.”
A Study of American Intelligence
Robert Yerkes
“All officers without exception agree that the
Negro lacks initiative, displays little or no
leadership, and cannot accept responsibility… All
officers seem further to agree that the Negro is a
cheerful, willing soldier, naturally subservient.
These qualities make for immediate obedience,
although not necessarily for good discipline, since
petty thieving and venereal disease are
commoner than with white troops.”
A Study of American Intelligence
Robert Yerkes
“The author presents not theories or
opinion but facts. It behooves us to
consider their reliability and their meaning,
for no one of us as a citizen can afford to
ignore the menace of race deterioration or
the evident relations of immigration to
national progress and welfare.”
A Study of American Intelligence
C. C. Brigham
“We have here an investigation
which, of course, surpasses in reliability all
preceding investigation, assembled and
correlated a hundred-fold. These army
data… give us a scientific basis for our
conclusions.”
Study of American Intelligence
• Northern blacks higher IQs than Southern
– Not due to less racism or better environment
– Northern blacks had “greater admixture of
white blood”
– North lured more intelligent blacks from South
Study of American Intelligence
• Nordics (“a race of soldiers, sailors,
adventurers, and explorers, but above all
of rulers, organizers, and aristocrats)
scored higher than Alpines (“submissive
to authority, the perfect slave, the ideal
serf, the model subject” and
Mediterraneans because of race
A Study of American Intelligence
C. C. Brigham
“Running parallel with the movements of
these European peoples, we have the most
sinister development in the history of this
continent, the importation of the Negro… The
decline of American intelligence will be more
rapid than the decline of the intelligence of
European national groups, owing to the
presence here of the Negro. These are the
plain, ugly facts that our study shows.”
A Study of American Intelligence
Henry Osborne
“I believe those tests were worth what the
war cost, even in human life, if they served to
show clearly to our people the lack of
intelligence in our country, and the degrees of
intelligence in different races who are coming to
us, in a way which no one can say is the result
of prejudice…”
A Study of American Intelligence
Calvin Coolidge:
“Biological laws show… that Nordics
deteriorate when mixed with other races.”
Boston Globe editorial:
“Danger that World Scum will
Demoralize America.”
Brigham called for…
“selective breeding [to create] a
world in which all men will equal the
top ten percent of present men.”
1922 Walter Lipman
Wrote series of 10 articles in the
New Republic attacking spreading
use of IQ tests, which he warned was
creating “an intellectual caste system
in which the task of education had
given way to the doctrine of
predestination and infant damnation.”
1930s: Brigham Recants
“Most psychologists working in the
test field have been guilty of a naming
fallacy which easily enables them to
slide mysteriously from the score in the
test to the hypothetical faculty
suggested by the name given to the
test.”
Brigham recants (con’t)
“The study with its entire hypothetical
superstructure of racial differences collapses.”
“Comparative studies of various national
and racial groups may not be made with
existing tests… One of the most pretentious
of these comparative racial studies – the
writer’s own – was without foundation.”
Charles Spearman
Believed IQ inherited
Eugenics advocate
Created factor analysis:
Showed intercorrelation
among Binet’s sub-tests
Two-factor theory:
g + s-s
Lewis Thurstone
Invented factor
rotation technique
Found 7 factors –
“Primary Mental
Abilities”
Primary Mental Abilities
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Verbal Comprehension
Word fluency
Number facility
Spatial visualization
Memory
Perceptual speed
Reasoning
David Wechsler
Developed W.A.I.S.
(Wechsler Adult
Intelligence Scale)
W. A. I. S.
W. A. I. S.