Chapter 11 - The mental states of agents

Abstract

Many instances of commonsense reasoning involve the mental states of agents. An agent is an entity that performs purposeful actions in the world in which it exists. In order to represent and reason about agent behavior—in particular, to interpret an agent's actions and make predictions about an agent's future actions—one must model the mental states of agents. This chapter addresses agent behavior, which requires the modeling of beliefs, goals, and plans. Then, discusses the modeling of emotions. Agent behavior can be reactive or goal-driven. Whereas some agent behavior is reactive, much behavior is goal-driven. a belief of an agent is a property considered by the agent to be true or false. A goal of an agent is a property that the agent desires to be true. An agent's plan for a goal consists of actions that the agent intends to perform in order to achieve the goal. An agent activates certain goals in certain situations. An agent's goals tend to persist until they are achieved. When an agent has a goal, the agent activates a plan for achieving the goal. When a plan is active, an agent tries to execute the plan. If a plan fails, an agent activates an alternative plan. When a goal succeeds, whether intentionally or accidentally, the goal and plan are dropped.