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)

Data from the Colorado Adoption Project for 493 first-grade adopted and nonadopted children are used to separate parental intelligence quotient (IQ) from the effects of school environment. Several of the variables show direct environmental associations with reading and mathematics achievement independent of effects of parental IQ. (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)