Understanding acknowledgements

As our ability to build robust and flexible spoken-language human-computer interfaces increases, we must consider whether and how we should incorporate various human-human discourse mechanisms into our dialogue models. In this dissertation I examine the use and probe the potential usefulness of one of these, acknowledgment. Acknowledgments signal understanding but not necessarily agreement; they serve to assure the conversants that information has been conveyed successfully. They also play a role in managing turn-taking.; Before we can incorporate acknowledgments in human-computer interfaces in an effective manner, there are several basic questions that should be answered. In this dissertation I report on a three-part research program in which I examine the use of acknowledgments in human-computer interaction from several perspectives: (1) Recognizing acknowledgments. How can acknowledgments be recognized using low-level prosodic features and contextual cues? In two studies, I analyze corpora of human conversation for prosodic and contextual cues that might be useful for recognizing that an acknowledgment has occurred. (2) Predicting acknowledgments. Can subjects predict where acknowledgments might occur in human-human dialogue? Two studies probed subjects' ability to determine whether acknowledgments might occur after a turn. (3) Eliciting acknowledgments. Are subjects are willing to use acknowledgments in human-computer interaction? I present and discuss a Wizard-of-Oz study in which subjects could control the presentation of information using either acknowledgments or commands.; By combining the three approaches, I was able to probe various aspects of the larger issue of understanding how and whether we should incorporate acknowledgments in spoken-language interfaces. Both the corpus studies and the perceptual studies suggest that dialogue-level context will be more important than local cues both for recognizing and for predicting (or generating) acknowledgment behavior in human-computer interfaces. The Wizard-of-Oz study shows that some subjects are willing to use acknowledgment as a turn-taking mechanism even in a fairly limited interface, although other subjects report resistance to the idea; more study is needed to understand the strength and implications of that resistance.