LECTURE 8 EXPERIENCING PREJUDICE II
Group Differences in Measurement of Intellectual Performance
Recall Major & O’Brien’s
MOVIE: Testing & Intelligence
- An IQ of a 100 shows that you are average in certain aspects of intelligence than
- Cognitive tests test your mental ability
- Personality tests test the non cognitive aspects of your personality like interests
- Projective tests like the Rorschach assess mental and emotional problems. The
random patterns reflect your innermost thoughts
- Holton tried to show that intelligence was hereditary/environment
- Bine’s test wanted to test the intelligence of school children. He quantified
o He tested many children of many ages; a norm was determined for each age .
o Other kids were then tested against the norm to determine their
- Statistics showed that blacks and immigrants were inferior
- Lewis Turman adapted Bine’s test for American school children, which led to the
introduction of the IQ; which was mental age/ chronological age x 100 = IQ. - Wexler developed non-verbal sections of the test so that language wasn’t a barrier.
This was small children and immigrants could also be tested.
- A test has to be valid (measures what it is supposed to measure). Because of this,
the test themselves need to be assessed and also how they are used/misused.
- Stereotype threat- effect that labelling and STs can have on a person’s ability to
perform in a given situation. Defined by Steele
- Just knowing that others can judge us based on our social identity is enough to
distort our performance
- Steele conducted a test where male and females had a math test.
o If a girl wrote the test when told that it does not test gender difference,
they scored the same as men; if a girl was told that it predicted gender
difference, women scored less than men because of the stereotype threat
men are better in math than women
Black-White IQ Distribution:
40 50 60 70 80 90 100 110 120 130 140 150 Male-Female Math Performance Difference:
0.3 High School
favouring males (d)
Magnitude of sex difference Junior High
- Males and females have the same performance in elementary school, but the
difference between them gets larger and larger as they progress through life
- Groups are different probably because they have different socializing
ORIGINS OF INTELLIGENCE: Nature or Nurture?
- Intelligence is highly heritable
High correlation between parent IQ and child IQ
IQ of identical twins is highly related; more than fraternals
IQ of identical twins reared apart is highly related
IQ of adopted children is related to IQ of biological mother, less related to
IQ of adopted mother
- Environment also plays role
IQ of identical twins reared apart is less related than IQ of identical twins
reared together IQ of fraternal twins is more strongly related than IQ of regular siblings
because they are treated more similarly and have the same 50% of genetic
make-up as their siblings
IQ of adopted kids are more similar than unrelated individuals reared apart
because of shared environments
Impoverished environments related to lower IQ
Nature vs. Nurture?
- Both Nature and Nurture contribute to intelligence
- But genetics certainly play role
Heritability index = 0.50 (may be as high as 0.65)
- If within-group difference has genetic component, perhaps between-group
difference has genetic component too.
No. Between-group differences may be caused by different factors than
Within vs. Between Group Differences
- Assumption that the height of the stalk is purely determined by the genetics of
the seed. In pot A, some are taller than others because they are genetically better;
same with the stalks in pot B.
- Pot A has rich soil, while pot B has poor soil (environmental factors).
- Within group (ex within pot A), the differences are caused by genetics, but
BETWEEN groups (between pot A and B) can't be explained by genetics because
the environment factor is involved. ***Why are groups different?
A: Not different
B: Tests are unfair
C: Different socializing environments
Does the Difference Exist?
- “Intellectual performance” (whether biased or not) reveal robust differences.
- BUT, what does this difference mean?
Black-White Mean Verbal SAT Gap
Are the Tests Unfair?
- The tests are culturally biased
External Bias- (external validity) - does this test predict real world
outcomes for people. Does it reveal differences in prediction for real
people? If you put blacks and whites who both score 100 on an IQ test, it’ll
predict slightly different things for blacks than for whites so there’s some
Internal Bias- is there something about the test itself that favors one
group over another? Environment
- SES and IQ are positively related
If groups are over-represented in low SES, will also be over-represented in
- Match Black-White environment:
Black children adopted by White parents have higher IQ than non-adopted
Difference in Black/White IQ diminished when socioeconomic status is