A computational mechanism for initiative in answer generation

Initiative in dialogue can be regarded as the speaker taking the opportunit y to contribute more information than was his obligation in a particular di scourse turn. This paper describes the use of stimulus conditions as a comp utational mechanism for taking the initiative to provide unrequested inform ation in responses to Yes-No questions, as part of a system for generating answers to Yes-No questions. Stimulus conditions represent types of discour se contexts in which a speaker is motivated to add unrequested information to his answer. Stimulus conditions may be triggered not only by the discour se context at the time when the question was asked, but also by the anticip ated context resulting from providing part of the response. We define a set of stimulus conditions based upon previous linguistic studies and a corpus analysis, and describe how evaluation of these stimulus conditions makes u se of information from a User Model. Also, we show how the stimulus conditi ons are used by the generation component of the system. An evaluation was c onducted of the implemented system. The results indicate that the responses generated by our system containing extra information provided on the basis of this initiative mechanism are viewed more favorably by users than respo nses without the extra information.