Racial Differences in IQ Revisited: A Synthesis of Nearly a Century of Research

Abstract

This article presents a synthesis of arguments disputing the existence of racial-ethnic differences in mental ability, and it challenges the classicist model of “intelligence” on which hereditarian assumptions of racial disparity are based. A review of the literature reveals the following eight major premises held by supporters of this perspective: (a) intelligence is unidimensional and can be represented by a single factor, g; (b) intelligence is fixed within individuals and across generations; (c) IQ tests accurately measure this fixed ability; (d) IQ tests are equally valid across racial, ethnic, and cultural groups; (e) intelligence determines individuals’ professional and social standings; (f) environment plays little role in determining an individual’s intelligence; (g) the intelligence of populations is deteriorating over time; and (h) scores on IQ tests are consistent with classical statistical and measurement theory. Each premise is refuted on the basis of historical, sociological, psychological, and statistical evidence.