Soar as a Unified Theory of Cognition: Spring 1990
Richard L. Lewis, Scott B. Huffman, Bonnie E. John, John E. Laird, Jill Fain Lehman · 1990
Soar is a theory of cognition embodied in a computer system. In 1987 it was used as the central exemplar to make the case that cognitive science should attempt unified theories of cognition (UTC) [13] 1. Since then, much research has been done to move Soar toward being a real UTC, rather than just an exemplar. Figure 1 lists the relevant studies 2. They have been done by a broad community of researchers in the pursuit of a multiplicity of interests. This symposium presents four of these studies to convey the current state of Soar as a UTC (their names are marked with asterisks in the figure). This short paper provides additional breadth and context. THE SOAR ARCHITECTURE We review here the basic structure of the Soar architecture, which has been described in detail elsewhere [8, 13, 20]. Soar formulates all tasks in problem spaces, in which operators are selectively applied to the current state to attain desired states. Problem spaces appear as triangles in Figure 2 (which describes a Soar system for comprehending natural language). Problem solving proceeds in a sequence of decision cycles that select problem spaces, states, and operators. Each decision cycle accumulates knowledge from a long term recognition memory (realized as a production system). This memory continually matches against working memory, elaborating the current state and retrieving preferences that encode knowledge about the