Rational communication in multi-agent environments

We address the issue of rational communicative behavior among autonomous se lf-interested agents that have to make decisions as to what to communicate, to whom, and how. Following decision theory, we postulate that a rational speaker should design a speech act so as to optimize the benefit it obtains as the result of the interaction. We quantify the gain in the quality of i nteraction in terms of the expected utility, and we present a framework tha t allows an agent to compute the expected utilities of various communicativ e actions. Our framework uses the Recursive Modeling Method as the speciali zed representation used for decision-making in a multi-agent environment. T his representation includes information about the agent's state of knowledg e, including the agent's preferences, abilities and beliefs about the world , as well as the beliefs the agent has about the other agents, the beliefs it has about the other agents' beliefs, and so on. Decision-theoretic pragm atics of a communicative act can be then defined as the transformation the act induces on the agent's state of knowledge about its decision-making sit uation. This transformation leads to a change in the quality of interaction , expressed in terms of the expected utilities of the agent's best actions before and after the communicative act. We analyze decision-theoretic pragm atics of a number of important kinds of communicative acts and investigate their expected utilities using examples. Finally, we report on the agreemen t between our method of message selection and messages that human subjects choose in various circumstances, and show an implementation and experimenta l validation of our framework in a simulated multi-agent environment.