Probabilistic Models for Agents' Beliefs and Decisions

Brian Milch
Daphne Koller

Abstract: Many applications of intelligent systems require reasoning about the mental states of agents in the domain. We may want to reason about an agent's beliefs, including beliefs about other agents; we may also want to reason about an agent's preferences, and how his beliefs and preferences relate to his behavior. We define a probabilistic epistemic logic (PEL) in which belief statements are given a formal semantics, and provide an algorithm for asserting and querying PEL formulas in Bayesian networks. We then show how to reason about an agent's behavior by modeling his decision process as an influence diagram and assuming that he behaves rationally. PEL can then be used for reasoning from an agent's observed actions to conclusions about other aspects of the domain, including unobserved domain variables and the agent's mental states.

Appeared in: Proc. 16th Conference on Uncertainty in Artificial Intelligence (UAI), 2000, pages 389-396. Runner-up for Best Student Paper award.

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