Abstract
Age-related differences in cognitive organisation reveal adolescents' failure to meet G. Polya's definitional and planning criteria for effective problem solving. Adolescents were less efficient and poorer in planning and adaptability than women, with only two completing the task successfully compared with eight women. There were qualitative differences in group metaplans and subsequent moves. Eight efficient women's metaplans were based either on time constraints or personal priorities. In contrast, only five adolescents expressed any plans that involved standing back from the task, and four of these only made plans for single errands so that each errand had to be re-planned. The task of organising an afternoon's errands allowed us to examine adolescents' spontaneous and induced planning on partially constrained problems. The chapter explores ways to observe adolescents' and adults' plans and self-regulation on constrained tasks like learning to use a computer, and school-related tasks like working on projects.