Influence of planning time and first-move strategy on Tower of Hanoi problem-solving performance of mentally retarded young adults and nonretarded children.

Because the ability to plan ahead is essential for successful solution of transformation problems, it is reasonable to assume that planning time will be positively related to performance. In two experiments using a computer-interfaced Tower of Hanoi problem, however, the planning time of retarded young adults was, on the average, as long as or longer than the planning time of higher performing nonretarded children. In neither group was there a reliable correlation between planning time and performance. There were group differences in preferred strategies, which we speculated were associated with a deeper search capacity available to the nonretarded children. What takes place during planning time is a more relevant source of group and individual differences than is the duration of planning time.