COGNITIVE SCIENCE 17, 1-6 (1993) Cognition in the Head and in the World: An Introduction to the Special Issue on Situated Action DONALD A. NORMAN University of California,San Diego This issue of Cognitive Science contains a debate among proponents of two distinct approaches to the study of human cognition. One approach, the tradition upon which cognitive science was founded, is that of symbolic processing, represented in the article by Alonso Vera and Herbert Simon. The other more recent approach, emphasizing the role of the environment, the context, the social and cultural setting, and the situations in which actors find themselves, is variously called situated action or situation cognition. It is represented by four articles written in response to Vera and Simon: James Greeno and Joyce Moore; Philip Agre; Lucy Suchman; and WilIiam Clancey. The debate was triggered by Vera and Simon's article, which takes note of the work in situated action and its attacks on the role of symbolic process- ing, and argues that the new approach could easily be incorporated within the old. The respondents take issue with this characterization. To understand the nature and importance of this debate, it is necessary to reflect a bit upon the social and personal nature of the scientific enterprise. In this introductory essay, I provide some background information and scope to the discussion that follows. The study of human cognition has matured. In the early days-not that long ago-the development of formal methods for the analysis of cognitive processes unleashed a vast uprising of research, all wildly optimistic about the promises of these methods for the study of cognition. Information- processing models of cognition developed rapidly. Studies of symbolic repre- sentation and what was called "the representation-of-knowledge problem" dominated the field. Progress was made on many fronts, including planning, problem solving, reasoning, and language. But after the initial flurry of activ- ity, progress slowed. The problems of understanding human cognition still loomed large. At first, it looked like all was within our grasp, now it appears that no matter how far we have come, we still have an equal distance to go. There are several reasons for the difficulties. Correspondence and requests for reprints should be sent to Donald A. Norman, Apple Computer, Inc., 1 Infinite Loop, Cupertino, CA 95014.