2006 PSnew
Commentary TheTotalityofAvailable EvidenceShowstheRaceIQGap StillRemains J. Philippe Rushton 1 and Arthur R. Jensen 2 1 The University of Western Ontario, London, Ontario, Canada, and 2 The University of California at Berkeley In a previous study (Rushton & Jensen, 2005), we examined 10 categories of technical research and concluded that the mean Black-White IQ difference in the United States is about 80% heritable. We reviewed evidence that (a) the distribution of IQ scores around the world shows averages of 106 for East Asians, 100 for Whites, 85 for U.S. Blacks, and 70 for sub-Saharan Africans; (b) race differences are most pronounced on the more g-loaded subtests (gbeing the general factor of mental ability); (c) race differences are most pronounced on the subtests whose scores show the most heritability; and (d) racial differences in brain size parallel the IQ differences. We also reviewed cor- roborating studies of (e) racial admixture, (f) trans-racial adoption, (g) regression to different racial means, (h) 60 related life-history traits, (i) human origins, and (j) the inadequacy of environmental explanations of the racial IQ difference. (In Af- rica, the 30-point difference is likely only 50% heritable be- cause environmental factors such as malnutrition and disease have so much more impact than they do elsewhere in the world; Lynn, 2006.) Dickens and Flynn (2006, this issue) challenge our hypoth- esis. They claim that ‘‘no one can really trace the Black-White IQ gap in the United States back to its origins’’ (p. 913) and that in the United States, Blacks have gained ‘‘4 to 7 IQ points on non-Hispanic Whites between 1972 and 2002’’ (p. 913). But to maintain that ‘‘no one can really trace the . . . gap back to its origins,’’ Dickens and Flynn had to sidestep our citation of Shuey’s (1966) review of the literature, which shows that Black- White IQ differences in the United States have remained at 15 to 18 points, or 1.1 standard deviations, for nearly a centur…