Prosodic correlates of disconfirmations

In human-human communication, dialogue participants are continuously sending and receiving signals on the status of the information being exchanged. These signals may either be positive ("go on") or negative ("go back"), where it is usually found that the latter are comparatively marked to make sure that the dialogue partner is made aware of a communication problem. This paper focuses on the users' signaling of information status in human-machine interactions, and in particular looks at the role prosody may play in this respect. Using a corpus of interactions with two Dutch spoken dialogue systems, prosodic correlates of users' disconfimations were investigated. In this corpus, disconfirmations may serve as a positive signal in one context and as a negative signal in another. Our findings show that the difference in signaling function is reflected in the distribution of the various types of disconfirmations as well as in different prosodic variables (pause, duration, intonation contour and pitch range). The implications of these results for human-machine modeling are discussed.