Race and IQ: A Theory-Based Review of the Research in Richard Nisbett ’ s Intelligence and How to Get It

Abstract

We provide a detailed review of data from psychology, genetics, and neuroscience in a point-counterpoint for- mat to enable readers to identify the merits and demerits of each side of the debate over whether the culture-only (0% ge- netic-100% environmental) or nature + nurture model (50% genetic-50% environmental) best explains mean ethnic group differences in intelligence test scores: Jewish (mean IQ = 113), East Asian (106), White (100), Hispanic (90), South Asian (87), African American (85), and sub-Saharan African (70). We juxtapose Richard Nisbett's position, expressed in his book Intelligence and How to Get It, with our own, to examine his thesis that cultural factors alone are sufficient to explain the differences and that the nature + nurture model we have presented over the last 40 years is unnecessary. We review the evidence in 14 topics of contention: (1) data to be explained; (2) malleability of IQ test scores; (3) culture- loaded versus g-loaded tests; (4) stereotype threat, caste, and X factors; (5) reaction-time measures; (6) within-race heri- tability; (7) between-race heritability; (8) sub-Saharan African IQ scores; (9) race differences in brain size; (10) sex dif- ferences in brain size; (11) trans-racial adoption studies; (12) racial admixture studies; (13) regression to the mean effects; and (14) human origins research and life-history traits. We conclude that the preponderance of evidence demonstrates that in intelligence, brain size, and other life history traits, East Asians average higher than do Europeans who average higher do South Asians, African Americans, or sub-Saharan Africans. The group differences are between 50 and 80% heritable.