A path model of genetic and family environmental transmission was fitted to published twin correlations and to general cognitive ability data from adoptive and nonadoptive families in which children were tested yearly through the fourth year. Longitudinal genetic correlations from infancy to adulthood were modeled explicitly, as were effects of…

Compares models of the classroom dynamics for a traditional laboratory setting and a problem-solving-centered environment, both at the eighth grade science level. Descriptive data indicate no differences in the models, whereas path analyses suggest that, in the problem-solving model, student behaviors significantly correlate to lesson structure,…