*Intellectual Development; Longitudinal Studies

Using data from a broader longitudinal study, this investigation explores within-subject and cross-generational stability of intellectual competence and the relationship of such stability to aggresgive behavior. Data were gathered three times (when subject's ' modal age was, 8, 19, and 30 years). Initially,. subjects included the entire population enrolled in the third grade in Columbia County, New York. While aggression and IQ scores were obtained for 632 subjects 8 years of age, samples available for multivariate analyses were much,smaller. All, however, were / sufficiently large to provide reasonable statistical power. / Additional measures of IQ or achievement were made when subjects were. 19 and 30 years old. When subjects were 8 years old, mothers and fathers were interviewed;'-when 30 years of age, data were gathered from the spouses and children. Measures relevant'to this study wer