Proceedings of the Annual Meeting of the Cognitive Science Society

Covert visual attention is a subtle part of human vision that has been widely researched in the psychology community. Most often visual attention is thought to involve movements of the eyes or head; however, covert visual attention does not involve overt movements of any sort. It has often been described in an homuncular sense as the "mind's eye." This paper introduces both a new model of covert visual attention and a new approach in which to investigate attention. The approach is based on five assertions: (1) Development of models of attentional processes should occur in the context of a fixed, explicit model of nonattentional processes. (2) Evaluation of attentional models should occur in the context of complete tasks. (3) Judgment of the quality of an attentional model should be with respect to its ability to cover many tasks while maintaining constant parameters. (4) Computer implementation and simulation of an attentional model and the tasks it claims to cover should be used for demonstrating its sufficiency. (5) A process model (a model that seeks to correspond at some level of analysis to actual mechanisms of behavior) should be able to account fw both the timing and the functions of behavior. N O V A (Not Overt Visual Attention), the first operator-based model of covert visual attention, is based on the Model Human Processor [Card, Moran, and Newell, 1983], a model of nonattentional processes that has been applied successfully in Human-Computer Interaction (HCI) research. In this paper w e review the results of using N O V A to model seven qualitatively different immediate-response tasks from the psychological literature. As a test of the sufficiency of N O V A , we implemented N O V A and each of the task models in the Soar cognitive architecture, a computer model of human behavior that has been proposed as the basis of Newell's "Unified Theories of Cognition" (UTC) [Newell, 1990]. N O V A is both a new theory of attention and a framework in which existing theories of attention have been unified.