Suggests some difficulties and challenges in understanding and teaching Piaget's new theory. Outlines some differences between Piaget's new and standard theories, such as the diminished status of the emergent skills that mark the onset of concrete operational thinking and the perception of achievements in concrete operations as empirical…

Outlines Piaget's late ideas on categories and morphisms and the impact of these ideas on the comprehension of the inclusion relationship and the solution of arithmetic problems. Reports a study in which fourth through sixth graders were given arithmetic problems involving two known quantities associated with changes rather than states. Identified…

Compares and demonstrates a correspondence between L. Kohlberg's stages of moral development and M. Douglas's grid/group theory. Reinterprets Kohlberg's findings and discusses limitations of both theories. (BJD)

Examination of the way in which children conceive the development of animals shows that there are parallels among concepts of development with those of the periods of concrete operations and formal operations. The conception of development seems to advance further in the subsequent period of dialectical thought. (MS)