Keeping the Initiative: An Empirically-Motivated Approach to Predicting User-Initiated Dialogue Contribution in HCI

Keeping the initiative: an empirically-motivated approach to predicting user-initiated dialogue contributions in HCI Kerstin Fischer and John A. Bateman Faculty of Linguistics and Literary Sciences and SFB/TR8 University of Bremen Bremen, Germany {kerstinf,bateman}@uni-bremen.de Abstract In this paper, we address the problem of reducing the unpredictability of user- initiated dialogue contributions in human- computer interaction without explicitly re- stricting the user’s interactive possibili- ties. We demonstrate that it is possible to identify conditions under which particular classes of user-initiated contributions will occur and discuss consequences for dia- logue system design. 1 Introduction It is increasingly recognised that human-computer dialogue situations can benefit considerably from mixed-initiative interaction (Allen, 1999). Interac- tion where there is, or appears to be, little restric- tion on just when and how the user may make a di- alogue contribution increases the perceived natu- ralness of an interaction, itself a valuable goal, and also opens up the application of human-computer interaction (HCI) to tasks where both system and user are contributing more equally to the task be- ing addressed. Problematic with the acceptance of mixed- initiative dialogue, however, is the radically in- creased interpretation load placed on the dialogue system. This flexibility impacts negatively on performance at all levels of system design, from speech recognition to intention interpretation. In particular, clarification questions initiated by the user are difficult to process because they may ap- pear off-topic and can occur at any point. But pre- venting users from posing such questions leads to stilted interaction and a reduced sense of control over how things are proceeding. In this paper we pursue a partial solution to the problem of user-initiated contributions that takes its lead from detailed empirical studies of how such situations are handled in human-human inter- action. Most proposed computational treatments of this situation up until now rely on formalised notions of relevance: a system attempts to inter- pret a user contribution by relating it to shared goals of the system and user. When a connection can be found, then even an apparently off-topic clarification can be accomodated. In our approach, we show how the search space for relevant connec- tions can be constrained considerably by incorpo- rating the generic conversation analytic principle of recipient design (Sacks et al., 1974, p727). This treats user utterances as explicit instructions for how they are to be incorporated into the unfold- ing discourse—an approach that can itself be ac- comodated within much current discourse seman- tic work whereby potential discourse interpreta- tion is facilitated by drawing tighter structural and semantic constraints from each discourse contri- bution (Webber et al., 1999; Asher and Lascarides, 2003). We extend this here to include constraints and conditions for the use of clarification subdia- logues. out.Our approach is empirically driven through- In Section 2, we establish to what extent the principles of recipient design uncovered for natural human interaction can be adopted for the still artificial situation of human-computer inter- action. Although it is commonly assumed that re- sults concerning human-human interaction can be applied to …

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