Stimulus variability and cognitive change

4 postulates of a tentative theory of cognitive change are presented. Implications of the postulates for response to stimulus variability as a function of age were tested in 4 studies (N = 863). Measures of response used were estimation accuracy, the ability to learn class names, the ability to classify, and changes in expressed preference after differential experience with stimulus variability. In each study children at 2 grade levels and adults responded to random shapes varying from 5-40 independent turns. Results supported the following conclusions: (1) Ss are sensitive to variability, (2) there is a limit on processing ability, (3) there are systematic effects of experience with variability on expressed preference, (4) young children tend to select from the presented variability. The postulation that experience with stimulus variability just beyond the limits of processing ability would result in maximal cognitive change received partial support. (20 ref.)