Confirmations and Joint Action

We argue t h a t cur ren t p lan-based theor ies o f discourse do no t by themselves exp la i n preva lent phenomena in even s imp le task -o r ien ted d ia logues. T h e purpose o f th is paper is to show how one d i f h c u l t t o e x p l a i n feature of these d ia logues, con f i rma t i ons , fo l lows f r o m the joint or t eam na tu re o f t he u n d e r l y i n g task. Speci f ical ly , we rev iew the concept of a j o i n t i n t e n t i o n and we argue tha t the conversants in a task -o r ien ted d ia logue j o i n t l y i n tend to accompl i sh the task . F r o m th is basis, we der ive the goals u n d e r l y i n g the pervasive use of con f i rma t ions observed in a recent expe r imen t . We conclude w i t h a discussion on genera l i z ing the analys is presented here to character ize d ia logue i tse l f as a j o i n t ac t i v i t y . 1 I n t r o d u c t i o n T h i s paper i s concerned w i t h ana lyz ing features o f comm u n i c a t i o n t h a t arise d u r i n g j o i n t o r t e a m ac t iv i t ies . Speci f ical ly, we discuss the o r i g i n o f t w o types o f conf i rmat ions: con f i rma t i ons o f successful f u l f i l l m e n t o f requests, and o f referent i den t i f i ca t i on . We show how the same u n d e r l y i n g p r inc ip les , n a m e l y the j o i n t na tu re o f the pa r t ne r s ' a c t i v i t y , gives rise to the goals under l y ing b o t h types o f speech acts. To make th is precise, we examine d a t a f r o m a s t u d y o f task-or ien ted dia logues, p rov ide a f o r m a l analys is o f j o i n t ac t i on , describe the sub jec ts ' task in the f o r m a l i s m , and then der ive the goals t h a t we c l a i m give rise to the con f i rma t i ons . B o t h types of c o n f i r m a t i o n , as wel l as requests for t h e m , occur repeated ly in the task-or ien ted dialogues for assembl ing a t oy wa te r p u m p s tud ied in [4, 12]. F i r s t , successful sa t i s fac t ion o f each request f r o m an exper t to an apprent ice was near l y a lways con f i rmed w i t h u t te r ances such as " G o t i t , " " O K , " o r " D o n e . " For examp le , 1 *Thi8 paper was supported by a contract f rom A T R Internat ional to SRI In ternat ional , by a gift f rom the Systems Development Foundat ion, and by a grant f rom the Natural Sciences and Engineering Research Counci l of Canada. The second author also wishes to thank the Department of Computer Science and the Center for the Study of Language and Informat ion at Stanford Universi ty where he was a visitor during the preparat ion of this paper. + Fellow of the Canadian Ins t i tu te for Advanced Research Dialogue fragments are quoted verbat im f rom transcripE x p : A n d a t tach the p i n k t h i n g so i t covers the hole in the m i d d l e . A p p r : (pause) Got it. One way-va lve .