The 'Jensen Effect' and the 'Spearman-Jensen Hypothesis' of Black-White IQ Differences

摘要

Arthur Jensen's research on the biological basis of mental ability has culminated in his encyclopedic new work The g Factor (1998) which massively confirms "Spearman's (1927) hypothesis" that Black-White IQ differences vary systematically as a function of each test's g loading. More generally, The g Factor consolidates the psychometric, neurophysiological, behavior genetic, and comparative evidence for the existence and importance of g, and links it to evolutionary processes. But perhaps Jensen's greatest legacy to science will be his pioneering method of correlated vectors which subsumes, under a much broader principle, his famous (1969a) hypothesis about the heritability of the Black-White IQ gap and, as Osborne (1980) dubbed it, the "Spearman-Jensen hypothesis" that Black-White IQ differences are greatest on the g-factor. Jensen's method of correlated vectors demonstrates that g (specifically a test's g loading) is the best predictor of that test's correlation with a given variable. In future, when a significant correlation occurs between g-factor loadings and variable X, the result might usefully be called a "Jensen Effect" (for that X variable), because otherwise there is no name for it, only a long explanation of how the effect was achieved. Naming it the "Jensen Effect" would honor one of the greatest psychologists of our time.