From Jensen's two-level theory of mental abilities it was predicted that forward digit span (FDS) should correlate less with IQ than backward digit span (BDS), and age and race should interact with FDS-BDS, with FDS-BDS difference decreasing as a function of age and a greater white-black difference in BDS than in FDS. (Author/BJG)

This study examines the nature of the highly variable black-white difference across diverse tests and indicates the major systematic source of this between-population variation, namely, Spearman's g. Eleven large-scale studies (discussed in the appendix), each one comprising anywhere from 6 to 13 diverse tests, show a significant and substantial…

The Kaufman Assessment Battery for Children (K-ABC) and the Wechsler Intelligence for Children-Revised (WISC-R) were compared with respect to the magnitudes of the average White-Black differences in standardized scaled scores and in raw scores. Subjects were 172 fourth- and fifth-grade children matched in Black-White pairs. (Author/LMO)

In a study of the relationship between speed of information processing and general intelligence, vocational college students (50 black males and 56 white males) took eight different reaction time tests measuring the speed with which individuals perform various elementary cognitive processes, and a group test of scholastic aptitude (the Armed…