100 and 120 for Jerry and Gerry respectively, 110 and 130 for Robin and Robyn
respectively, and 120 and 140 for Sara and Seri respectively. Yet the correlation
between the IQ scores of the twins will still be 1.0, because correlations reflect
rank order, which remains the same. This hypothetical example makes clear
that even when the correlation between twins reared apart is as high as it can
be (1.0), the environment can still dramatically affect group differences in IQ
performance.
Why Are There Ethnic Differences in IQ Performance? If differences in IQ perfor-
mance among ethnic groups are not due to genetics, what are they due to?
Nobody knows for sure (Neisser et al., 1996). A clue comes from the finding
that many politically and economically disadvantaged groups from all over the
worldtendtodolesswellinschoolandtoscoreloweronIQ-typeteststhando
the more advantaged groups (Ogbu, 1978, 1994). The kinds of minority groups
that score lower on IQ tests are those that became a minority group involun-
tarily or those that are regarded by the culture as caste-like (Ogbu, 1978, 1994).
Immigrants who come to a country voluntarily may be optimistic that they
can control and improve their conditions. These groups typically do well on
IQ tests. Groups that are involuntarily displaced, such as Native Americans,
African Americans, and the Maori in New Zealand, or are excluded, like the
‘‘untouchables’’ of India or non-European Jews of Israel, may lack the convic-
tion that hard schoolwork and serious commitment to the educational enter-
prise will be rewarded. It is these groups that tend to do poorly on IQ tests.
Furthermore, IQ tests take place in settings in which motivation and attitudes
can affect performance (see Helms, 1992; Miller-Jones, 1989). Children from a
minority culture that emphasizes the interpersonal nature of learning may be
more likely to regard a lack of feedback from the tester as evidence that they
are doing well on the test (Miller-Jones, 1989). These children may refrain from
varying their strategies in the course of taking the test and consequently obtain
a lower score. In some cultures, it is unusual for an adult who already knows
the answer to a question to ask that question of a child, or for children to ex-
plain what they know (Heath, 1989; Rogoff & Morelli, 1989).
It is frequently observed that people from other cultures often misunderstand
the instructions and fail to take seriously the test’s requirements. Sinha (1983),
for example, has provided an analysis of some of the cultural reasons why
Asiatic Indians who have not been enculturated by the West have trouble with
IQ tests. Asiatic Indians typically do not know that responses like ‘‘I don’t
know’’ or ‘‘I can’t decide’’ will cause one to get lower scores on IQ tests. Also,
Asiatic Indians are typically inhibited in responding, especially when the task
seems pointless to them. In some cultures, such as the culture in which many
African Americans are raised, a premium is placed on the creativity of re-
sponses. Sometimes African-American children are surprised to learn that they
are expected to provide obvious answers on IQ tests (Heath, 1989; Helms,
1992). The creative answers they often do provide get them lower scores. Boy-
kin (1994) argues that many African Americans are alienated from education
and the accompanying psychometric enterprise because these institutions
implicitly conflict with a heritage that emphasizes spirituality, harmony, ex-
pressive individualism, communalism, and orality, and not talent sorting and
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