Issues in Multiparty Dialogues Ronak Patel

Current Trend  Only two-party case (a person and a Dialog system  Multi party (more than two persons Ex. Classroom, group meeting )

Current Systems

Issues  Participant Roles (Who is who case, contains both local roles that shift during the conversation, such as speaker and hearer etc.)  Interaction Management (Who speaks when, what is the topic under discussion, what communicative channels are used )  Grounding and Obligations (What are common beliefs & a promise, acknowledgment, or agreement (as a contract) that binds one to a specific performance )

Problems  What patterns of information exchanges do conversational participants form?  Patterns of initiative taking  Data Collection

Participant Roles  Conversational Roles  In two party scenario basic roles of speaker and listener/addressee  In multiparty scenario issues of Who receive an utterance and who is it address to  Example A -> B (A want C listen) D hear the Q without A’s intention.  Listener is in –context or out of context (interpret utterance quite differently)

Participant Roles  Speaker Identification  In two party scenario not big deal (any speech that does not come from oneself must come from the other participant)  In multiparty scenario microphone arrays can localize the position of the speech, and give us clue of who is the speaker

Participant Roles  Addressee Recognition  In two party not big deal (whoever is not speaking)  In multiparty scenario we must separate hearers and addresses  Hearer can be found by properties like volume – level of speech, distance etc  Addressee – A speaker directly indicate either by name or role also context can also work as clue in this case. Eg. Who had previously spoken or been addressed.

Participant Roles  Other Participant Roles  Other than conversational roles, one can have specific task roles, relating participant to particular task.  Like agent who is authorized to tell team member to carry out the task, one can have agent as guards also, making sure that task is not performed.  In multiparty this roles become more complex imagine a court room environment.  Social Roles - status (superior, equal), closeness (friend, colleague) will influence the kinds of interaction allowed..

Interaction Management  Turn Management  Deals with Q of when to speak and when to stop?  Depends on languages & cultures.  One way is that speaker should give some verbal or non-verbal signals of continuation or termination.  But in Multiparty its more complex  as more agents = more competition of taking turn = more actions possible  Speaker suggest the next one, if not then than it will be free competition for the floor.  Likelihood of someone speaking decays with the no of turn in the discussion since he last spoke.

Interaction Management  Channel Management  Uni-model communication systems (phone) Channel Management = Turn Management  In multi-channel system issue of which channel to use for which content, also timing of contribution.  Channels can be using same (radio with different frequencies) or different modalities (speech for communication and video for attention and understanding)  In multiparty dialog system we can use multiple main-channels e.g., one per topic, one per conversation

Interaction Management  Thread/Conversation Management  Concerns what is being communicated (which topic discussed when, how to organize the progression of topic)  Stack – based topic organization – a traditional way  multiple conversation is more complex  One solution is to have Multiple conversation Models.  Problem might arrive when multiple conversations are not completely independent. (e.g., share participant)  Problem become more worse with multiple participants and multiple conversations which may share participants.  Solution is to use number of relationships (e.g., addressee and conversation, topics and conversations)

Interaction Management  Initiative Management  Concerns Which agent is currently setting the agenda for topics.  Two-party dialogue system are either user-initiative or system- initiative  Mixed-initiative allows user and system both to take the initiative at different points.  Cross-initiative, where a responder does not take initiative herself, but redirects it to a third party  Cross-conversation initiative, where one conversation being dependent on another…

Interaction Management  Attention Management  Mostly assumed to be present (Takes binary value).  In multiparty situations more detailed model required  Can summon others into new or existing conversation.  Can model which conversation each participant is attending to

Grounding & Obligation  Grounding  Process of adding to the common ground between participants in conversation.  In multiparty situations which model to use is less clear  One way is to allow any of the addressee to acknowledge for the contents to be considered grounded (Problem some agents did not in fact understand)  Another way is to require evidence of understanding from each addressee (its unrealistic)  Middle-Grounding is required.  Grounding across conversations (A ask Q to B – B ask same Q to C, A has evidence B has understood Q, even B has not responded A )

Grounding & Obligation  Obligation  Requests or Q can be treated as obligation  In presence of multiple addresses, its not clear what the status of these obligations, Does every addresses have a personal obligation? etc  Issue of transfer of obligation (Refer to previous Example)  One Model is to use obligation as motivation (track obligations and then use these to motivate performing answers)  Another model is to use dialogue structural considerations as Questions Under Discussion (QUD), which represents information about what would count as an answer, while obligations represent who should/must answer.

Problems  Scene: Three party dialogues using the task of scheduling meetings.

Discussion Structure

Problems  The conclusion here is that two-party interactions are dominant in three-party dialogues.  Initiative taking behavior is more clearly observed in three-party dialogues than those in two-party dialogues. (emergence of an initiative-taker or a chair person)  Collecting Data in naturalist setting is difficult and expensive. (commitment to the task)

Conclusions  Treat multiparty conversation as a set of pairs of two-party models  Simple & use existing models  Less satisfaction  Move beyond the two party case,helps to arbitrate between the multiple interactions.  Bit more complex  Some cases we can see two-party dialogues as a special simple case of multiparty dialogue.

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