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No. 362980715 File1321053133.png -(91 KB, 854x697, 1319499684177.png ) >Psychology, Public Policy, and Law, 11, 311-319. >Because
differences in material resources across a broad range of family
circumstances seem to have no demonstrable effect on IQ by late
adolescence, culture-only theories have now begun to stress
psychological rather than material disadvantage as the root cause of
group differences in cognitive performance: for example,
racism-depressed motivation, racial stress, race-based performance
anxiety ("stereotype threat"), and low self-esteem. All are generally
posited to result in some manner from White racism. However, there is no
evidence that any of them causes either short- or long-term declines in
actual cognitive ability, either within or between races; not all of
them (e.g., self-esteem) are lower for Blacks; and none can begin to
explain the large array of relevant non-psychological facts, including
why the races also differ in brain size and speed (in milliseconds) of
performing exceedingly simple cognitive tasks such as recognizing which
of several buttons on a console has been illuminated (a reaction time
task). Because the American Black-White IQ gap has not narrowed in the
century since it was first measured, the psychic injury must also be
just as deleterious now as it was during that earlier, more hostile era
for Blacks, which seems implausible. Thus, while the proposed psychic
insults may temporarily patch over some rips in the culture-only theory,
they would seem to hold even less promise than the failed socioeconomic
ones for explaining the longstanding, worldwide pattern of racial IQ
differences and their links to the biological correlates of g. 
