Examines preschoolers' understanding of non-observable causal mechanism in causes of illness. Three studies were conducted using subjects from university child care centers. Subjects average five years of age. Results indicated that preschoolers recognize that appearances may be deceiving when it comes to judging causes of illness. Discusses…

Distinguishes the values of quantitative increments and qualitative shifts with regard to problem solving. Subjects were 136 children ranging from 6 through 8 years and were presented with the standard 3-disc problem to resolve in 3 minutes. Results indicated that qualitative shifts in children's representation of problem space are a crucial…

Examines the ability of infants to track and anticipate the final orientation of an object. Subjects were infants ranging from an average of four months to eight months old. Three experiments, with the last one as control, were carried out. Concludes that infants show some rudimentary mental rotation from four months of age. (MOK)