Findings from a study reported in this paper indicate that the differences in family background that affect IQ are largely the result of genetic differences among parents, which affect the parents' own status attainment and which are passed on genetically to their offspring, whose status attainments are subsequently affected. (Author/EB)

Genetic effects on specific cognitive abilities as distinct from those on general cognitive ability were studied in 302 pairs of twins (some reared together, some apart) from the Swedish Adoption/Twin Study of Aging. Overall, results showed significant genetic influence on specific abilities independent of influence on general ability. (SLD)

Examined low achievement in normal-or-above intelligence early adolescents born preterm, in a longitudinal study from birth through 12 years of age, compared to a group with no achievement problems. Found significant group differences in several domains in early adolescence. Also found that biological and social factors in infancy were associated…

Social behaviors among girls (ages 6-16) with fragile X (n=8) or Turner syndrome (n=9) were examined to address the role of family environment versus biological determinants of social dysfunction. Compared to their sisters, subjects had lower IQS and higher rating of social and attention problems. (Author/CR)

Composite reading performance data from 223 pairs of identical twins and 169 same-gender fraternal twins in which at least one member was classified with reading disability were subjected to multiple regression analysis. Results indicated that the genetic etiology of reading disability differs as a linear function of IQ. (Contains extensive…

A study designed to examine biological, sociological, and early maturational correlates of intelligence collected data prospectively, from birth to 15 years of age, on a sample of 987 black children. Multiple indicators of eight independent and three dependent variables were tested in a structural equation model. Altogether, clear sex differences…

This paper critically examines the portions of Arthur Jensen's books, "Genetics and Education" and "Educability and Group Differences," that concern Barbara Burks' 1928 study of adoptive families. Jensen cites the low correlations of children's IQs with measures of home environment from Burks' study as evidence that environment…