Examined consistency of hand preference in a longitudinal study of children between 18 and 42 months of age. Results showed a sex-specific relationship between hand consistence and intellectual development. Females with consistency of handedness were precocious compared to females without such consistency; the same relationship did not hold for…

Sex difference research has been plagued with a myriad of problems,. Specifically, intelligence testing, if dependent on measurement of spatial or verbal proficiency, may not be an accurate indicator of native ability. Similarly, infrequent replication of studies, studies that only include subjects of one sex yet imply sex differences, and poor…

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.…