Implications of the Cattell-Horn-Carroll theory on ethnic differences in IQ

The Cattell-Horn-Carroll theory of intelligence and the Spearman-Jensen hypothesis were applied to help interpret mean IQ differences among ethnic groups. The Cattell-Horn-Carroll theory classifies cognitive abilities on three strata, which differ by magnitude of generality including specific, broad, and general abilities. The Spearman-Jensen hypothesis advances the belief that mean IQ differences between African Americans and Euro-Americans occur as a function of the test's g loadings. Although IQ differences between African Americans and Euro Americans occur, the differences should be larger on tests with higher g loadings and smaller on tests with lower g loadings. The analysis described in this paper may serve as the catalyst to encourage all intelligence test publishers to supply test users with data regarding mean IQ differences among various ethnic groups.