Cultural bias

Human Mental Abilities
Lecture 6
Leonardo Gabales
Group Differences in Intelligence
Group differences considered here:
Socio-economic status
Why are individual differences psychologists interested
in group differences?
Mainly because of the social effects of the misuse (& abuse?) of
intelligence test scores
Test Bias
Bias refers to a test showing differences when no real
differences exist
Establishing the presence of bias requires a criterion
against which the test can be validated:
E.g., If it is known that blacks & whites perform equally well at a
particular job, but a test used to select personnel for that job
indicates significant black/white differences - then the test is
said to be biased
However, if test score differences correspond to criterion
differences - the test cannot be said to be biased
Group Differences: SES
Socio-Economic Status (SES) differences
SES is defined by several indicators
Often related to “social class”
Considered a latent variable - in the sense that
it is defined by several indicators (like IQ)
Group Differences: SES
Correlation between SES & IQ is between .5 - .7
This relationship between SES & IQ might be interpreted
in 2 ways:
Tests of intelligence are biased in favour of middle-class white
Anglo-Saxon groups – such groups & their social values,
dominate upper strata of SES
Tests are valid measures of a socially-important construct
Occupational Selection Bias
Occupational selection bias has been
examined carefully during the past two decades
& many jobs & tests have been scrutinised
The issue was tested in a series of court cases
in the USA contesting the employment decisions
based on intelligence test scores:
Many challenged ‘positive discrimination’ whereby
people with higher test scores were passed over in
favour of members of culturally disadvantaged groups
Occupational Selection Bias
It became accepted that each selection test should have
a proven validity for a particular job
This had practical consequences:
It was thought that tests of general intelligence should be
replaced by tests of specific abilities that may have higher
validity for particular jobs
Faced with increased costs of research & administration, many
corporations abandoned the use of tests altogether
This course of action appears poorly justified
SES & IQ: Concluding Remarks
Tests of intelligence appear to correlate with
SES because they are valid measures of a
socially important construct
Differences between various occupational status
categories seem to be real & intelligence tests
appear to be sensitive to these effects
But remember, the correlation between
SES and IQ isn’t 1.0…
Group Differences: Race & Ethnicity
Race: a population of people who share a common pool
of genes that differ from those of other races
This often leads to characteristic physical attributes (e.g., skin
colour, height, blood-group) which are used to identify a race
Ethnic group: a society consisting of people who share
the same customs, culture, traditions, language, religion,
Often, these people constitute a single nation or tribe; they
might tend to interbreed- thus sharing a common gene pool - but
this is not a necessary condition as it is with race
Group Differences: Race & Ethnicity
The largest number of studies of racial differences has
been carried out in the USA - comparing performance of
blacks & whites
A well-established finding is that, on the average, US blacks
perform about 1 SD below US whites on intelligence tests
This means that, on IQ tests that have a mean of 100 & standard
deviation of 15, the average performance for African-Americans is
about 85
It is interesting, however, that in infancy (until the age of 4) black
children show superiority over whites on sensory motor tasks
that are used as early measures of intelligence
“All our social policies are based on the fact that their
intelligence is the same as ours whereas all the testing
says not really”
(James Watson, speaking about Africa)
Group Differences: Race & Ethnicity
Another racial comparison that has recently
become ‘fashionable’ is Whites vs Asians:
Asians tend to score 3 to 5 IQ points better
overall, show superior non-verbal & quantitative
abilities, & have somewhat inferior verbal abilities
This is usually attributed to high values placed on
achievement & education in Asian societies
Debate: Racial & Ethnic Differences
There has been considerable debate on the
causes of these racial differences:
Some extreme Darwinist claims have been
e.g., African-Americans are less intelligent than
whites because slaves brought from Africa were less
intelligent than their peers who evaded capture
The truth is… we do not really know what
causes (or how to reduce) racial differences
Debate: Racial & Ethnic Differences
There are probably many different factors involved…
Debate has focused on the role of environmental & genetic
factors in causing race differences in intelligence
Jensen & Eysenck used a ‘plausibility argument’ in
support of genetic causation:
Because genetic determination of within-group differences has
been well established, it is plausible that between-group
differences are similarly determined
Jensen ultimately abandoned this argument
Environmental Factors (?)
Evidence from empirical studies has also been
African-Americans living in the northern USA tend to obtain
higher scores than those living in the south
Importantly the North has a higher standard of living & better
educational system
This is also true for urban vs rural comparisons
These results have generally been used as evidence for
the environmental position
Selective Movement
HOWEVER … group differences in test
scores may also be attributed to selective
i.e., movement of more intelligent populations
away from impoverished environments
Does this salvage the genetic argument (?!)
Cultural Bias
Cultural bias is important – particularly
regarding racial differences
It is argued that apparent racial differences stem
from tests assuming dominant culture values
that are foreign to minority subcultures (e.g.,
Afro-Americans, especially the poor)
Thus members of minority groups might score poorly,
not because they are less able, but simply because
they don’t understand the questions
Cultural Bias: Example
This accusation has been tested in a study
comparing performance on a culturally sensitive
verbal intelligence test for 3 different cultural
groups - British, African-American & US whites
As expected, African-Americans tended to score
lower than US Whites
Also, British were closer in test scores to US Whites
than to African-Americans
Cultural Bias: Results
The most important evidence for cultural differences,
however, was found in the patterns of item difficulty:
Items that were difficult for African-Americans were also difficult
for US Whites
Other items were difficult for both US groups, but were not
difficult for British, & vice versa
Cultural differences between US blacks & whites appear
to be smaller than cultural differences between the
Americans & the British
Cultural Bias: Conclusions
Generally, if some items are more difficult for one group
than they are for another group, & if the situation is
reversed for other items, there is evidence of cultural
In the above study, this was true for American groups vs.
British, but not for African-Americans vs US Whites
Within Group Differences (i.e., Americans) were small – BUT –
Between Group Differences (i.e., African-Americans + US
Whites vs British) were much larger
Cultural Deprivation
Advocates of environmental causation for race
differences often introduce the concept of
cultural deprivation
This claim is difficult to investigate & there is
some disconfirmatory findings:
Native Americans & those of Spanish descent tend to
score higher than African-Americans, yet their
environmental & cultural handicaps are also serious
Radical Cultural Relativism Hypothesis
The precise meaning of cultural differences & their
implications for intelligence are not well understood
The radical cultural relativism hypothesis proposes
that there are no (cross culturally) universal cognitive
Thus: descriptions & assessments of cognitive capacity must be
culturally valid - i.e., sensitive to the cultural context in which
they are applied
Cross-cultural comparisons would therefore be impossible
Radical Cultural Relativism Hypothesis
Less radical positions allow for comparisons
when cultural differences are taken into account
In contrast, other positions allow for the
possibility that psychological universals exist
Comparison between racial or ethnic groups using
traditional intelligence tests are valid
Studies of Australian Aboriginals
Have traditionally reported low (often 1 SD+ lower than
‘average’) levels of intelligence- but many studies are
dated (pre-WWII)
Recent anthropological studies suggest that aspects of
Aboriginal culture seem to emphasise abilities that may be
poorly sampled by the typical intelligence tests
E.g., abilities associated with reasoning based on spatial
relationships – which are of cultural significance to Australian
It has also been argued that Aboriginal cultures emphasise
collectivist values
This might impair children’s ability to develop abilities fully within the
individualist mainstream culture
Studies of Australian Aboriginals
One study has shown that on a particular test involving
memory for spatial relationships (rural) Aboriginal
children outperform white Australians
Children were tested for recall of locations of objects within a
matrix, with the response being to actually position the objects
correctly within the matrix
Results indicated that Aboriginal children used visual encoding
strategies that were superior to the white children’s verbal
rehearsal strategies
Group Differences: Gender
There are many differences (i.e., inequalities)
between males & females within our society
HOWEVER: substantial changes have taken
place over the past half-century
Some differences that were considered to be innate &
therefore unchangeable are obviously not so
It is hard to say how many of these differences will
disappear in a near future - overall, it appears that
females are still disadvantaged in our society
Gender & Earnings
Significant differences exist in earnings between
males & females in our society
In 1969, women in full-time employment earned about
58% of men’s average weekly earnings
By 1973, the figure had improved to 73%
In 1994, the figure had further improved to 80%
In 2007, women earned about 90% of men’s average
weekly earnings
Gender Earnings Ratio
Gender & Scholastic Achievement
It has been claimed that over recent years boys have
become the weaker sex in education - perhaps as a
result of all the changes that have taken place in girls'
Prior to the 1980s boys (on average) outperformed girls in the
HSC – this difference between genders was minimal by 1980-81
By 1993 girls (on average) outperformed boys in the HSC by
more than 12 marks - girls also outperformed boys in five of the
eight key learning areas, by 1996 this difference was almost 20
For all subjects, a higher proportion of boys tended to cluster at the
bottom of the mark range
At the top of HSC scores there are still more boys than girls but the
difference has diminished considerably over the past 5 years
Gender Differences in TE scores
Changes in average Tertiary Entrance Scores (HSC) for boys & girls
between 1981 & 1996
Gender & Scholastic Achievement
15 years ago, only one-third of the top 1000 students
were girls - today the ratio is closer to being 60-40 in
favour of girls
Full circle? - new programs have been suggested to redress the
differences between boys & girls!
BUT: do these trends reflect true differences in ability?
There is a large body of literature that compares males &
females with respect to their performances on cognitive tests
“The chief distinction in the intellectual powers of the
two sexes is shewn by man's attaining to a higher
eminence, in whatever he takes up, than can woman
- whether requiring deep thought, reason, or
imagination, or merely the use of the senses and
(Charles Darwin)
Gender & Cognitive Ability
Earlier studies tend to report large differences
E.g., girls were found to have superior verbal ability, particularly
verbal fluency - boys tended to score high on mechanical tasks
There have been several lines of explanations of gender
Cultural & social factors were seen as being particularly
important - girls do not have equal opportunity after school
There are personality differences - docility & submissiveness in
girls - restlessness & greater physical activity of boys lead to
different lifestyles & career paths
Gender & Cognitive Ability
Boys & girls mature at different rates (girls mature about
two years earlier than boys) which may cause
differences in achievement
Neuropsychological differences – there exist
differences in brain structures (e.g., the hypothalamus) &
in cerebral lateralization in males & females
Hormonal differences especially in androgen/estrogen
ratio may be related to (some) cognitive abilities
Gender & Cognitive Ability
However… gender differences in cognitive
ability are changing – the differences between
males & females tend to diminish with
successive generations
“Gender differences are small and disappearing …”
The following data clearly demonstrates
changes across time in differences in actual
performance on psychological tests
Male-Female Differences in IQ Units
Mech. Reasoning
Spatial Relations
Verbal Relations
Abstract Reasoning
Num Reasoning
Gender & Cognitive Ability
For many abilities - e. g., Verbal Reasoning, Abstract
Reasoning, Numerical Reasoning - these differences are
not significant
The only difference in this Table that remains significant to this
day is for Mechanical Reasoning - males are clearly superior to
females in dealing with mechanical & spatial problems
It seems likely that this difference will remain significant in the
However, in our work with the Gf/Gc test battery, we
have repeatedly found no overall gender differences in
Gender & Cognitive Ability
This general trend of decline in gender
differences argues against biological
explanations & implicates changes in our culture
Factors such as sexual stereotyping of different
activities, interests, & curricular choices among high
school students may be important factors
The only exception to this general conclusion is
spatial/mechanical abilities…
Gender differences in these abilities cannot be
accounted for by explanations in terms of cultural
Girls Just Want to Have Sums
Gender Differences in Spatial Ability
Biological explanations of differences in spatial ability are
in terms of:
Sex-linked gene for spatial ability
Differences in the degree of cerebral lateralization - males are
more lateralized than females
it is assumed that the right cerebral hemisphere which is
responsible for performance on spatial tasks is more specialized in
males than in females - females are said to use a more ‘integrated’
mode of thinking than males
Hormonal differences, especially androgen/estrogen ratio.
At this stage, it is not clear which one of these three
explanations is the most adequate - they may all be
closely related
Gender & Cognitive Ability
While the overall differences in cognitive abilities seem
to have disappeared, two findings regarding gender
differences have gained in prominence:
1st FINDING: significant gender differences on some
types of tasks exist in samples that are above average
in ‘general ability’
Even though overall mean difference between males & females
in numerical & mathematical tasks is small, there are a
disproportionate number of males who show high mathematical
Gender & Cognitive Ability
2 main explanations have been offered:
Mathematical ability may be dependent on spatial/mechanical
abilities & since males are superior on these latter types of
abilities, they tend to obtain higher scores on tests of
mathematical ability
Small differences in central tendency may imply large
differences at the extremes of the distribution - there will be a
disproportionately large number of males with high scores
i.e., This difference is due to statistical properties of the distribution
of scores, not to a manipulation of social conditions in favor of
Gender & Cognitive Ability
2nd FINDING: there are significant differences in
variability between males & females - there is a greater
variability among males than among the females in many
psychological traits
There are more males in jails, in psychiatric institutions, etc.
At the same time, there is a large proportion of males than
females among the high achieving members of our society
Overall, in many personality traits, the range of scores for males
is greater than the range of scores for females
Gender & Cognitive Ability
Several recent large-scale studies indicate that variance of males on
general intelligence tests is about 10% larger than variance of females
Thus, even though arithmetic means for these two groups do not differ
significantly, the spread of scores is clearly different
As a consequence, one finds more males than females among both highperforming groups AND among low-achieving groups
Male mean
Female mean
Test Score
Stereotype Threat
People from disadvantaged groups (e.g.
ethnic minorities and women) may
worry about conforming to negative
May view testing as less important
because “they’ll just be bad at it anyway”
Heightened test anxiety
Stereotype Threat
When exposed to stereotype threat, blacks
often do worse than whites on problem
Remove the stereotype and the differences often
Women often do worse in mathematics when
exposed to stereotype threat
This difference generally vanishes when the
stereotype threat is removed
At least one study has shown that women are
actually better than men at mathematics once the
stereotype threat is removed
Stereotype Threat
White males aren’t immune either
White male engineering students did worse in
mathematics when told that they were
participating in research to determine why Asians
were better at mathematics
Asian females and mathematics
When their gender was made salient they did
But when their ethnicity was made salient they did
Group differences in intelligence…
Race differences
an advantage (on average) in test scores for those with higher
significant advantages (overall) for US Whites over US Blacks,
US Asians over US Whites (although difference is modest), &
Australian Whites over Australian Aboriginals
Gender differences
Overall, are small & disappearing – an advantage for females in
some domains of verbal abilities, & for males in
spatial/mechanical abilities