How to Juggle Discourse Obligations

Author: Jameson, Anthony and Weis, Thomas

Editor:

In the context of dialog, one challenge for natural language generation is that of dealing with >discourse obligations< such as those created by questions, promises, and even silences. The present paper presents new methods for (a) representing discourse obligations, (b) determining which ones are created by a given dialog move, (c) determining how the status of an existing obligation is changed by a new move, and (d) taking existing and resulting obligations into account in the generation of new moves. The task of choosing a dialog move (which may consist of a signal for the user to produce the next utterance) is conceptualized in terms of the maximization of expected utility. This quantitative approach makes it possible to do justice to observations such as the following: (a) Discourse obligations lead to trade-offs with the system's other dialog goals. (b) Obligations differ in terms of their importance and the time within which they are to be fulfilled. (c) The severity of the consequences of nonfulfillment of an obligation depends on the relationship between the obligated speaker's moves and the total set of existing obligations.