Heredity and Environment

Psychology, Public Policy, and Law 2005, Vol. 11, No. 2, 302–310

Copyright 2005 by the American Psychological Association 1076-8971/05/$12.00 DOI: 10.1037/1076-8971.11.2.302

HEREDITY, ENVIRONMENT, AND RACE DIFFERENCES IN IQ A Commentary on Rushton and Jensen (2005)
Richard E. Nisbett
University of Michigan J. P. Rushton and A. R. Jensen (2005) ignore or misinterpret most of the evidence of greatest relevance to the question of heritability of the Black–White IQ gap. A dispassionate reading of the evidence on the association of IQ with degree of European ancestry for members of Black populations, convergence of Black and White IQ in recent years, alterability of Black IQ by intervention programs, and adoption studies lend no support to a hereditarian interpretation of the Black–White IQ gap. On the contrary, the evidence most relevant to the question indicates that the genetic contribution to the Black–White IQ gap is nil.

Rushton and Jensen’s (2005) article is characterized by failure to cite, in any but the most cursory way, strong evidence against their position. Their lengthy presentation of indirectly relevant evidence which, in light of the direct evidence against the hereditarian view they prefer, has little probative value, and their “scorecard” tallies of evidence on various points cannot be sustained by the evidence.

The Current Difference in Intelligence Between Blacks and Whites
One of the most serious misrepresentations in Rushton and Jensen’s (2005) article is their claim that the current difference in IQ between Blacks and Whites is slightly more than 15 points, or 1 standard deviation. The best evidence we have indicates that that value is out of date and that the Black–White IQ gap has lessened considerably in recent decades (Grissmer, 1994; Grissmer, Flanagan, & Williamson, 1998; Grissmer, Williamson, Kirby, & Berends, 1998; Hedges & Nowell, 1998; Nisbett, 1995, 1998). We do not have actual IQ scores available to establish this point

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