Race and IQ
Historical misuses and contemporary issues
Race and IQ
 The history of IQ testing
 A brief introduction to IQ tests
 Race-group differences
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A summary of the issue
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Possible explanations
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Test bias
Genetic differences
Environmental differences
A long (and mostly sordid) history
Craniometry (1860)
 Pierre Brocca
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Believed brain size=intelligence
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Interesting methods…
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Concluded:
“The brain is larger in mature adults than in
the elderly, in men than women,…in superior
races than in inferior races”
(Brocca quoted by Gould, 1978, p. 44)
Alfred Binet
 Lawyer, self taught in psychology,
studied under Charcot (who also
influenced Freud)
 Asked by French government to create
a test to identify students who would
benefit from remedial education
 Along with Theodore Simon, created
first widely-used standardized test of
intelligence, the Simon-Binet Scale
The birth of the IQ test
 France legislates mandatory primary education in 1882
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Government requests test to identify students who need “special ed.”
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Alfred Binet publishes (with Theodore Simon) the first widely-used
standardized IQ test (with 30 subtests) the Simon-Binet Scale (1905)
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Digit repetition
Sentence completion
Point to an object in a picture
Conscious recognition of resemblances
 How are a fly, an ant, a butterfly, a flea alike?
 In what way are a newspaper, a label, a picture alike?
Recognition of food
Moral judgment
Revised scale published in 1908
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14 tests retained, 9 dropped, 7 modified, 33 added
If 75-90% of children in age group pass, it was assigned that age level
Rejected notion of “IQ”
Henry Goddard
 Translated Simon-Binet into English (1908)
 Distributed 22,000 copies of translated test
across the U.S.
 Set up first laboratory to study mental retardation in New Jersey:
Vineland Training School for Feebleminded Girls & Boys
 Strong advocate of eugenics
 1912 book The Kallikak Family: A Study in the Heredity of
Feeble-mindedness
 original article
 summary and analysis
Goddard (continued)
 Wanted to prevent the breeding of feebleminded people
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hesitated to promote compulsory sterilization, even though
convinced it would solve problem
suggested "colonies" where the feeble-minded could be
segregated
 Established an intelligence testing program on Ellis Island in 1913
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rejects 80% of “pre-identified” immigrants as "feeble-minded"
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83% of all Jews
80% of the Hungarians
79% of the Italians
87% of the Russians.
 resulted in an exponential increase in deportations
Goddard (continued)
 The Immigration Restriction Act (1924-1965)
 Strongly influenced by American eugenics' efforts
restricted numbers of immigrants from undesirable racial
groups (including Jews).
 Upon signing, President Coolidge commented, "America
must remain American."
 Publicized race-group differences on Army IQ tests and
claimed Americans were unfit for Democracy
 One of many scientists (including Galton and Terman)
that inspired scientific racism movement in Europe &
U.S.
Robert Yerkes
 Founded first non-
human primate
research lab
 Chaired committee that
created the Army Alpha
and Beta intelligence
tests used in U.S.
during World War I
David Wechsler
 Born in Rumania, emigrated to
U.S. at age 6
 Worked as a psychological
examiner in army during WWI
 Obtained Ph.D. in 1925
 Chief psychologist at Bellevue Psychiatric
Hospital from 1932-1967
 Developed several intelligence tests, including
Wechsler Adult Intelligence Scale (WAIS) and the
Wechsler Intelligence Scale for Children (WISC).
WAIS Popularity
WAIS
Defining Intelligence
 “Global capacity to act purposefully, to think
rationally, and to deal effectively with the
environment” (David Wechsler)
 1987 survey of 1020 experts on intelligence
 Abstract reasoning (99.3%)
 Problem-solving ability (97.7%)
 Capacity to acquire knowledge (96.0%)
 Memory (80.5%)
 Adaptation to environment (77.2%)
Intelligence vs other types of tests
 Aptitude tests measure a narrow range of ability
 Achievement tests measure what you know or
what you learned/achieved
Question: What is the SAT?
Answer: A multiple aptitude test (related to intelligence)
SAT to IQ conversion table
SAT
V+M
IQ
15 SD
%ile
SAT
V+M
IQ
15 SD
%ile
1600
152.18
99.975
1010
109.46
73.587
1590
151.45
99.970
1000
108.74
71.985
1580
150.73
99.964
990
108.01
70.338
1570
150.00
99.957
980
107.29
68.647
1560
149.28
99.949
970
106.56
66.916
1550
148.56
99.940
960
105.84
65.149
1540
147.83
99.929
950
105.12
63.347
1530
147.11
99.916
940
104.39
61.516
1520
146.38
99.901
930
103.67
59.659
1510
145.66
99.883
920
102.94
57.780
1500
144.94
99.863
910
102.22
55.883
1490
144.21
99.840
900
101.50
53.972
1480
143.49
99.813
890
100.77
52.052
1470
142.76
99.782
880
100.05
50.128
Relationship between SAT and IQ
 1. For SAT scores before 1996
IQ = (0.126 x SAT combined) + (-.4.71E - 5 x SAT combined x
SAT combined) + 40.063 (Detterman and Frey, Case Western
Reserve Univ.)
 2. For SAT scores from 1996 -2004
IQ =(0.095 X SAT Math) + (0.003 X SAT Verbal) + 50.241 Scores
for SAT were "re-centered" in 1996, raising the average SAT
back to 500 (Detterman and Frey, Case Western Reserve Univ.)
 “SAT to IQ conversion is an inexact science, particularly for SAT's
under 900. The chart's creator writes: "The lowest point of
reference was the theoretical average IQ of high school students
being 110 and the current average SAT I V+M (verbal + math)
score being 1019. Everything below that is extrapolation. Also
note that the decimal places give the impression that the numbers
are more precise than they really are."
WAIS Verbal Subtests
WAIS Performance
Subtests
Picture Completion
Picture Arrangement
Block Design
Object Assembly
Digit-Symbol Substitution
Interpreting IQ scores
Interpreting IQ scores (normal curve)
The Flynn Effect (1995 data)
 IQ scores tend to rise 3 points every 10 years
Does IQ matter?
 How can we tell?
 Data indicate
 IQ and school performance (GPA)
 r=.50 for elementary and high school students
 r=.40 for college students
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IQ and years of education (r=.50, see next slide)
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IQ and occupational attainment (r=.50)
Likely due to very high correlation (r= mid .60s)
between education and occupation
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IQ and job performance (rs= .27 to .47)
IQ and Education
IQ and education/occupation (same data)
IQ tests’ strengths and weaknesses
The IQ racial gap
Possible explanations for the gap
 The tests are bad
 Genetic differences
 Environmental differences
Are the tests (racially) biased?
 Argument 1: IQ tests yield race-group differences, hence
the tests are biased
 Argument 2: The test item content is culturally biased
Example: “What
should you do when
a child smaller than
you begins to fight
with you?”
(comprehension)
Chitling Intelligence Test (Dove, 1971)
A "handkerchief head" is:
(a) a cool cat
(b) a porter
(c) an Uncle Tom
(d) a hoddi
(e) a preacher
Many people say that "Juneteenth" (June 19) should be made a legal
holiday because this was the day when:
(a) the slaves were freed in the USA
(b) the slaves were freed in Texas
(c) the slaves were freed in Jamaica
(d) the slaves were freed in California
(e) Martin Luther King was born
(f) Booker T. Washington died.
CB
Black Intelligence Test of Cultural
Homogeneity
 100-item multiple-choice test, based on items drawn from Black
culture
 Sample Questions
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1. Alley Apple is
a) brick
b) piece of fruit
c) dog
d) horse
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2. CPT means a standard of
a) time
b) tune
c) tale
d) twist
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3. Deuce-and-a-quarter is
a) money
b) a car
c) a house
d) dice
A, A, B
Are the culture-specific tests valid?
 Useful for building self-esteem
 But low predictive validity
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Low correlation between “Black” IQ Test and
achievement (Language =. 33, Math=.18)
Students in MR classes did no better on the
“Black” IQ Test than on the WISC
Cultural bias data
Are the tests (racially) biased?
 Argument 3:
The tests have
different construct
validity for Blacks
and Whites
Are the tests (racially) biased?
 Argument 4:
The tests have
different/inadequate
predictive validity for
Blacks and Whites
B.I.T.C.H. correlations:
Language =. 33
Math=.18
IQ and Education (1990)
Are the tests (racially) biased?
 Argument 5:
The tests have language bias because they are in
standard English and many Blacks grow up speaking
a Black dialect
Are the tests (racially) biased?
 Argument 6:
The tests are neutral but the examiners are biased
Evidence:
25 of 29 studies published prior to 1995 found no
significant relationship between the race of the
examiner and Black children’s scores
Are the tests (racially) biased?
 Argument 7:
The tests are neutral but the norms are inappropriate
In other words: Separate (rather than national) norms
should be used to eliminate racial bias [recent example]
Logical outcome (if taken to logical conclusion):
1. Race group differences would be eliminated, but…
2. Scores would have little relevance to racial justice, and
3. Scores would not allow tracking of group
outcomes/disparities
Possible explanations for the gap
 The tests are bad (no empirical support for
current racial bias!)
 Genetic differences
 Environmental differences
The heritability of IQ
Historical and current understanding
 Heritability debate has a long, controversial history
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In the 1960's Arthur Jensen fueled debate with heritability
estimate of .8
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The Bell Curve (1994) by Herrnstein and Murray
 Contemporary consensus
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Evidence does exist for high heritability, but
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Environmental factors are also important
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Studies show heritability = .4 to .8 (best estimate probably .7)
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High heritability does not discount environmental influence. Consider
vocabulary
So are psychological factors (e.g., Carol Dweck’s work)
The genetic position
A. Assumptions
1. IQ is polygenetic (Gottesman’s model postulates 5 genes)
2. IQ is normally distributed
3. Very low IQ is produced by genetic abnormalities
B. Evidence
1. Average IQ correlation of identical twins is .86
2. Identical twins, fraternal twins, siblings, and parent-child IQ correlations
all higher than that of unrelated persons
3. Parent-child correlations are higher for biological vs adopted parents
4. When siblings are reared together, IQ correlations are higher for
biological siblings than for adopted siblings
5. The high correlation in #1 resists change over time
6. Many genetic abnormalities have been proven to cause lower IQ
a. Turner’s syndrome
b. Fragile X syndrome
c. PKU
The environmentalist position
A. Assumptions
1. Genetics alone cannot account for the normal range of IQ
2. IQ is not necessarily normally distributed (tests are designed to yield a
normal distribution)
B. Evidence
1. IQ corrs of identical and fraternal twins raised together are higher than
for those raised apart.
2. Fraternal twins IQ correlations are higher than siblings’s IQ correlations
3. Assortative mating
4. Adoptive parent-child correlations are higher than unrelated adults and
children
5. Studies of environmental influences on IQ show that
a. Low birth weight decreases IQ
b. Malnutrition decreases IQ
c. Family background affects IQ
d. Pressure to achieve increases IQ
e. Birth order and family size affect IQ
f. Amount and quality of schooling affects IQ
But is the racial gap genetic?
Hard to determine due
to environmental
differences.
Is the racial gap genetic?
Many controversial “studies”
Between-group vs within-group variation
What we know about IQ heritability
 There is strong evidence of within-group heritability
 Laws of heredity produce regression to the mean
 There is a certain environment by gene interaction
What we know about IQ heritability
(cont.)
 1987 survey of 1020 intelligence experts
 The difference is entirely due to environmental variation: 15%.
 The difference is entirely due to genetic variation: 1%
 The difference is a product of genetic and environmental variation: 45%.
 The data are insufficient to support any reasonable opinion: 24%.
 No response (or not qualified): 14%.
 Robert Sternberg: "science isn't done by majority rule"
 APA 1997 task force: “It is sometimes suggested that the
Black/White differential in psychometric intelligence is partly due to
genetic differences. There is not much direct evidence on this point,
but what little there is fails to support the genetic hypothesis.”
 Charles Murray: “Actually, there is no direct evidence at all, just a
wide variety of indirect evidence, almost all of which the task force
chose to ignore.”
Possible explanations for the gap
 The tests are bad (no empirical support)
 Genetic differences (data mixed, no consensus)
 Environmental differences
Environmental Factors
 Social class and home environment matter
 Attribution of intelligence matters (Dweck)
 Motivation and test taking stills matters
 Stereotype threat matters
 Interventions matter
Scores have narrowed in past 30 years
Social Class matters
Bell curve, 1994
Family Factors and IQ
R2=.0576
Home environments
Environmental Factors
 Social class and home environment matter
 Attribution of intelligence matters (Dweck)
 Motivation and test taking stills matters
 Stereotype threat matters
 Interventions matter
Stereotype threat matters
Stereotype threat literature
Steele and Aronson (1995)
Ryan and Anthony (2006)
Interventions matter
Recent NY
Times article:
Who gets to
graduate?
The Culture of Poverty (Kutner, 1975)
Blaming the victim (Ryan, 1976)
Four Steps to Blaming the Victim
1. Identify a social problem
2. Study those affected by the problem to discover how
they are different from those who are not affected by
the problem.
3. Define the difference as the cause of the problem itself
4. Create a humanitarian action (social service) program
to correct the problem cause (from #3)
Real-world example:
http://www.whitehouse.gov/news/releases/2005/03/20050307-5.html
Blaming the (IQ) victim
1. Social problem:
African American children underperforming
(relative to Whites) on IQ tests
2. Study those affected by the problem to discover
how they are different from those who are not
affected by the problem
1.
2.
3.
4.
Black families more likely to be less educated
Black families more likely to have poor study spaces
Black children more likely to be unmotivated to do well on tests
Black children less likely to associate education with success
Blaming the (IQ) victim, continued
3. Define the difference as the cause of the
problem itself
Black children under-perform on IQ tests
because Black families don’t value education
4. Create a humanitarian action (social service)
program to correct the problem cause
?