Much recent cognitive and artificial intelligence research has focused on the development of "schema theory." This theory supposes the existence of knowledge structures that encode prototypical descriptions of familiar concepts. Schema theory has developed in a scientific environment that stresses interdisciplinary approaches to the study of intelligent behavior (cognitive science). Consequently, much of the development of schema theory as a descriptive theory of behavior has emphasized its theoretical utility and generality. In contrast, few rigorous tests of the theory have established its psychological validity. Nevertheless, schema theory provides a promising framework for the development of prescriptive methods for learning and reasoning. In particular, schemata may provide (1) memory organizations for use in rapidly acquiring new knowledge, (2) representations for problem-solving strategies, and (3) multi-dimensional data structures for use in problems requiring situation assessment.