In order to gather data bearing on the effects of individual differences of the "invariant stages" assumption of cognitive-developmental theory, 270 black, Chinese, and white subjects from 5th, 7th, and ninth grades were administered a new, 25-item, spatial reasoning task. It was predicted that age, ethnic group, and sex would…

This study investigated several levels of internal and external disequilibrium and their interaction. Subjects were 63 fifth graders assigned to three groups according to their degree of internal disequilibrium. Internal disequilibrium was measured by the amount "level mixture" (a tendency to respond to various events at several…