Recognizing Digressive Questions

When people interact, they sometimes ask questions that digress from the purpose of the discussion. It is important for a system that interacts with people to be able to distinguish these questions, from questions that are truly incoherent. The two types of questions require different treatment. Whereas the former type may require focusing the discussion, the latter type signals a misunderstanding that requires clarification and repair. The Interactive Discourse Planner is designed to plan text to describe and/or justify a domain plan interactively. The system I have designed and implemented uses questions from a user to recognize how to extend its own text plan in a way that both satisfies the user and achieves its own discourse goal. In the process, IDP can detect questions from the user that initiate a digression. As a testbed for my model, IDP plans text to discuss driving routes. Grosz and Sidner describe a digression as a type of interruption. Interruptions are utterances that don’t fit in with the discourse [GS86]. They note that interruptions take several forms ranging from ones that do not have any relevance to the ongoing discussion, to interruptions that are quite relevant. A digression is a relevant interruption. It is a discourse segment with a purpose that does not contribute to the purpose of the interrupted segment. However, it is linked to the interrupted segment by a common discourse entity. IDP operates in a cooperative interactive mode in which the system is the primary speaker and the user is the primary listener. The system controls the discussion to make its own intentions clear and to try to achieve them. In the IDP model, a digressive question occurs when the user asks a question that no longer addresses the system’s discourse purpose.