Forward and backward digit span interaction with race and 10: A longitudinal developmental comparison

The study sought to use Jensen's two-level theory of mental abilities to predict some hitherto unknown or unnoticed phenomena--facts about which the theory should yield clear-cut predictions and which are not as clearly predictable from other theories, though they may receive ad hoc explanations after the fact. From the two-level theory of mental abilities (Level 1: rate learning and memory, involving little or no transformation of the input; Level 2: complex cognitive processing involving transformation and mental manipulation of input) 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 the FDS-BDS difference decreasing as a function of age and a greater white-black difference in BDS than in FDS. The latter prediction is derived from the hypothesis that the magnitude of racial differences should be a function of the degree to which Level 2 predominates in the cognitive demands of the particular test. The predictions were substantiated at a high level of significance!n large representative samples of white and black children of ages 5-12 years, who were given the Wechsler Intelligence Scale for Children (Revised). Supplementary studies found no support for rival hypotheses based on anxiety, task difficulty, and race of examiner. (Author/JM