Agent-based simulation of human social behavior has become increasingly important as a basic research tool to further our understanding of social behavior, as well as to create virtual social worlds used to both entertain and educate. A key factor in human social interaction is our beliefs about others as intentional agents, a Theory of Mind. How we act depends not only on the immediate effect of our actions but also on how we believe others will react. In this paper, we discuss PsychSim, an

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... lemented multiagent-based simulation tool for modeling social interaction and influence. While typical approaches to such modeling have used first-order logic, PsychSim agents have their own decision-theoretic models of the world, including beliefs about their environment and recursive models of other agents. Using these quantitative models of uncertainty and preferences, we have translated existing psychological theories into a decision-theoretic semantics that allow the agents to reason about degrees of believability in a novel way. We demonstrate the expressiveness of PsychSim's decision-theoretic implementation of Theory of Mind by presenting its use as the foundation for a domain-independent model of appraisal theory, the leading psychological theory of emotion. The model of appraisal within PsychSim demonstrates the key role of a Theory of Mind capacity in appraisal and social emotions, as well as arguing for a uniform process for emotion and cognition. Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.