Four models are discussed with which to view students, educational goals, and learning environments. Each of the four theories emphasizes a unique aspect of the total development process. Piaget's model describes the development of structures and processes which characterize mature logical thinking. Perry provides a closer look at students' beliefs, about the nature of knowledge and authority, identifying and chronicling epistemological assumptions that profoundly affect students' reactions to and ability to learn from various instructional strategies. Relationships between Perry's "positions" and Erikson's model of identity development are described, and their implications for curriculum design explored. Finally, Kohlberg's stage theory and Gilligan's critique of that theory provide two perspectives on the development of systems for analyzing moral and value issues, and suggest instructional processes most likely to enhance this development. Each of these four theories is briefly summarized and a critique provided, followed by an analysis of the specific implications of the theory for teaching and learning in the colleges in Project Quality Undergraduate Education. Fifty-eight references are listed. (KM)