Plan-based models of dialogue

This paper reviews plan-based models of dialogue. The original model is thoroughly presented. Important developments of the original model are also presented. Finally, benefits and drawbacks of plan-based approaches to dialogue modelling are discussed. Introduction Plan-based dialogue models have since long earned their place in works intended to present computational linguistics in general and dialogue systems in particular (Allen, 1995; Jurafsky and Martin, 2000; McTear, 2002). Plan-based models of dialogue have accomplished to offer a generalization where dialogue can be treated as a special case of rational non-communicative behaviour (Cohen, 1996). This paper intends to review plan-based models from when they first appeared and onward. The starting point is taken to be the seminal work of Cohen, Perrault, and Allen (Cohen and Perrault, 1979; Perrault and Allen, 1980; Allen and Perrault, 1980). Plan-based Models of Dialogue Plan-based models of dialogue can be claimed to originate from three classic papers: Cohen and Perrault (1979), Perrault and Allen (1980), and Allen and Perrault (1980). Perhaps, the easiest way to introduce this class of models is to start with an intuitive description of what happens when an agent A asks another agent B a question, to which the latter then responds. The presentation is taken from Allen and Perrault (1980). A has a goal to acquire certain information. This causes him to create a plan that involves asking B a question. B will hopefully possess the sought information. A then executes the plan, and thereby asks B the question. B will now receive the question and attempt to infer A’s plan. In the plan there might be goals that A cannot achieve without assistance. B can accept some of these obstacles as his own goals and create a plan to achieve them. B will then execute his plan and thereby respond to A’s question.