Support for the confluence model of intellectual development has come from analyses of family size-birth order means of large aggregate data sets. Analyses of individual scores do not substantiate the confluence model, as explained variance is markedly reduced. The study of family interaction variables utilizing longitudinal data is recommended.…

According to confluence theory, a child is helped or hindered in intellectual development according to the average absolute intelligence (mental age) in the family when the child is born. An analysis of test scores, family information, and socioeconomic data of 36,000 college applicants in Colombia failed to support this theory. (Author/CP)

This study focuses on the effects of family size and spacing on intellectual, social, and personality development of children. The sample consisted of 533 suburban, middle class, large family (five or more) and small two child family children. The children, 233 boys and 300 girls, were teenagers attending either junior or senior high school.…