This paper synthesizes two perspectives on essentialism: cognitive and social. The cognitive essentialist perspective argues that our bias to appeal to the psychological belief that categories have innate essences enables us to make inferences about social categories such as race, caste, and gender. The social essentialist perspective argues that…

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…

Comments on Moshman's discussion, in this issue, of reasoning as self-constrained thinking, arguing that differences in type of reasoning constraint probably reflect different knowledge bases but do not necessarily imply different processes. The fact that different tasks require different kinds of knowledge does not mean that different processes…

Determines patterns of differential human development in a longitudinal study of 417 male and 358 female college students ages 18 to 30. Findings suggest individuality in development is associated with significant qualitative individual differences that are best described on a cross-time basis. (BJD)

Proposes a theory of reasoning and outlines four general types of reasoning (case-based, law-based, coherence-based, and dialectical) based on the constraints the reasoning seeks to honor. The development of reasoning is presented as a continuing construction and reconstruction of self-constraints and justifications for those constraints,…

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)