Despite the forbidding air that envelops the topic, ethnic differences in cognitive ability are neither surprising nor in doubt. Large human populations differ in many ways, both cultural and biological. It is not surprising that they might differ at least slightly in their cognitive characteristics. That they do is confirmed by the data on ethnic differences in cognitive ability from around the world. One message of this chapter is that such differences are real and have consequences. Another is that the facts are not as alarming as many people seem to fear.
East Asians (e.g., Chinese, Japanese), whether in America or in Asia, typically earn higher scores on intelligence and achievement tests than white Americans. The precise size of their advantage is unclear; estimates range from just a few to ten points. A more certain difference between the races is that East Asians have higher nonverbal intelligence than whites while being equal, or perhaps slightly lower, in verbal intelligence.
The difference in test scores between African-Americans and EuropeanAmericans as measured in dozens of reputable studies has converged on approximately a one standard deviation difference for several decades. Translated into centiles, this means that the average white person tests higher than about 84 percent of the population of blacks and that the average black person tests higher than about 16 percent of the population of whites.
The average black and white differ in IQ at every level of socioeconomic status (SES), but they differ more at high levels of SES than at low levels. Attempts to explain the difference in terms of test bias have failed. The tests have approximately equal predictive force for whites and blacks.
In the past few decades, the gap between blacks and whites narrowed by perhaps three IQ points. The narrowing appears to have been mainly caused by a shrinking number of very low scores in the black population rather than an increasing number of high scores. Improvements in the economic circumstances of blacks, in the quality of the schools they attend, in better public health, and perhaps also diminishing racism may be narrowing the gap.
The debate about whether and how much genes and environment have to do with ethnic differences remains unresolved. The universality of the contrast in nonverbal and verbal skills between East Asians and European whites suggests, without quite proving, genetic roots. Another line of evidence pointing toward a genetic factor in cognitive ethnic differences is that blacks and whites differ most on the tests that are the best measures of g, or general intelligence. On the other hand, the scores on even highly g-loaded tests can be influenced to some extent by changing environmental factors over the course of a decade or less. Beyond that, some social scientists have challenged the premise that intelligence tests have the same meaning for people who live in different cultural settings or whose forebears had very different histories.
Nothing seems more fearsome to many commentators than the possibility that ethnic and race differences have any genetic component at all. This belief is a fundamental error. Even if the differences between races were entirely genetic (which they surely are not), it should make no practical difference in how individuals deal with each other. The real danger is that the elite wisdom on ethnic differences—that such differences cannot exist—will shift to opposite and equally unjustified extremes. Open and informed discussion is the one certain way to protect society from the dangers of one extreme view or the other.
