Three studies were conducted to investigate reasons for the difficulties that children under 5 years of age experience with class inclusion tasks. The studies tested the claim that such tasks have a structural complexity that is beyond the children's processing ability. In experiment 1, class inclusion tasks were compared with other classification…

Discrimination learning set performance was examined in preschool children as a function of age and number of trials per problem. Subjects were 120 children three, four, five, and six years old. (MP)

Six same-different matching tests, both verbal and nonverbal in three modalities along with a set of reading tests, were administered to 120 Israeli children in second, third and fourth grade. (MS)

Reports the results of two experiments dealing with children's visual and tactual performance. In the first task, after several presentations of a series, the tactual group made almost errorless discriminations. But with memory demands, tactual performance became poorer than visual performance. Found a large developmental difference. (JAC)