Believer project

Understanding actions involves inferring the goal of the actor and organizing the actions into a plan structure. The BELIEVER system is a psychological theory of how human observers understand the actions of others. The present theory is concerned with single-actor action sequences and can account for goal-directed actions that may succeed or fail in accomplishing the goal, as well as actions governed by norms. Arguments are presented which show that the human process of plan recognition cannot be modeled using a generate and test paradigm. A paradigm, referred to as the hypothesize and revise paradigm, does capture important properties of human plan recognition performance. Our implementation of a plan recognition process using this paradigm is presented and discussed.