Forty-eight male and 54 female left-handed junior college students in Stockholm were grouped according to familial sinistrality and strength of handedness. Performance on computerized reaction time (RT), maze, and verbal ability tests was assessed. Sex was the only factor differentiating left-handers on RT, and no factors affected verbal ability.…

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)

The general intelligence factor (g) was investigated using 170 university students across three batteries of ability measures: (1) a short-term memory battery; (2) the Multidimensional Aptitude Battery; and (3) a reaction time battery. Results support the notion of g and suggest short-term memory as an essential aspect of intelligence. (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)

Groups of retarded and nonretarded children were investigated as they learned three rules underlying problems adapted from the Raven Progressive Matrices Test: rotation, imposition, and subtraction. Results were seen as consistent with theories that emphasize transfer flexibility as one potential source of individual and comparative differences in…

Intelligence quotient (IQ) test performance is reported for 93 families restudied 10 years after the Minnesota Transracial Adoption Study in 1975. Results for 426 subjects support the original finding: being reared in the IQ test culture and prevailing school culture benefits all children's IQ scores and academic achievement. (SLD)

The effects of early educational intervention on the attainment of the Piagetian cognitive stage of concrete operations by 86 socioeconomically disadvantaged children aged 5, 6, and 7 years were assessed. The Concept Assessment Kit-Conservation developed by M. L. Goldschmid and P. M. Bentler (1968) was used. (SLD)

Two studies (N=4,261 persons) illustrate an inverse relationship between ability level and correlations among IQ measures. Low IQ subjects showed higher correlations than did high IQ subjects. Intercorrelations of IQ subtests, intercorrelations of cognitive ability measures, and correlations of IQ with measures of cognitive ability displayed the…

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)