Individual differences in digit span, susceptibility to proactive interference, and various aptitude/achievement test scores were investigated in two experiments with college students. Results indicated that digit span was strongly correlated with aptitude/achievement scores, but did not indicate that susceptibility to proactive interference…

A reanalysis of Stephens' intercorrelations of Wechsler subtests, achievement tests, and Piagetian tasks was conducted. (EJ 055 112) Piagetian tasks contributed almost equally to the definition of the general factor in intelligence along with the Wechsler subtests and the achievement tests. Communality outweighed differences between intelligence…

Genetic and environmental etiologies of individual differences in tests of intelligence and school achievement were investigated in a study from the Colorado Adoption Project. A multivariate conditional path model was fitted to general cognitive ability and reading performance data from 119 adoptive and 120 nonadoptive families. (SLD)