Lower class black and lower class white first-grade children learned an unorganized and an organized list of words to test Jensen's hypothesis of racial differences in mental abilities. Both groups of children performed significantly better on the organized list with comparable means for each list. Most of the predicted relationships were not…

Rote learning and retention performance was studied as a function of method used in original learning and as a function of intellectual level. Sixty educable mentally retarded and 60 mentally normal junior high school students were randomly selected and assigned to one of three treatment groups, each learning to a different criterion, for each…

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…