Using a modified Posner "encoding function" methodology, group differences in semantic encoding speed were assessed under conditions in which subjects encoded pictures of common objects to determine physical identity matches, name identity matches, and superordinate identity matches. Results of primary interest revealed group differences in basic…

This study evaluated the diagnostic validity of a task measuring abstract categorization ability in learning disabled (LD) and non-LD children. Data showed that the component of abstract category knowledge that best disciminates LD children from non-LD, is the knowledge of how members of abstract categories differ from each other. (Author/JAZ)

Models of working memory were compared in 2 experiments as means of explaining variance in the comprehension of 95 skilled and 80 learning-disabled readers from grades 4 through 7. Results suggest that learning-disabled children's working memory problems are functionally related to higher order processes and not memory alone. (SLD)

Two studies with 658 white and 353 African-American elementary school children performing reaction time tasks are offered in support of Spearman's hypothesis about the relative size of the mean African-American-white differences on mental tests as a function of the tests' loadings on psychometric "g." (SLD)

A comparison was made of ability and achievement test results and school grades for 323 pairs of Swedish male and female twins and 740 controls in relation to social background. An interaction effect of sex and social background was found for verbal ability and mathematics test results. (SLD)