Persuasive Listener in a Conversation Elisabetta Bevacqua, Chris Peters, Catherine Pelachaud (IUT de Montreuil - Paris 8)

Conversation The conversation plays an important role in social interaction It allows the transmission of knowledge, feelings and needs of human beings Two fundamental participants: –Speaker –Listener Screenshot from « When Harry meets Sally »

The role of the listener Usually we are not consciously aware of the behaviour of listeners It becomes evident when the listener lacks such behaviour If the listener does not give any feedback, it is like speaking to a mockup The conversation is difficult and unsatisfying and the listener is not credible

Goals –Investigate the creation of a model for generating persuasive Embodied Conversational Agent (ECA) in the role of listener –Persuasive listeners make speaker aware that they are really paying attention to the conversation –Test the effects of different feedback on the persuasive abilities of an ECA To construct a model, need… –To define the appropriate feedback that a listener ECA should give –To know the effects of different feedback on a human perception of the agent

Possible feedback (1) Gaze –One way in which a listener can indicate attention is by gazing at the speaker –Averting the gaze could signal boredom or disinterest Head nod –It allows the listener to show agreement or disagreement –Head movement can also show confusion bending the head slightly on the right or on the left Facial expressions –Through facial expressions a listener can show that he\she is following the speaker, undertanding him/her –They also indicate agreement or disagreement showing anger makes disagreement clear

Possible feedback (2) Paraverbals –They are sounds such as “m-hm”, “aha” etc. that the listener uses to let the speaker know that he/she is listening and following the conversation Eyes blinking –Blinking rapidly could mean confusion and uncertainty Torso orientation –If the listener turns away, he/she has probably lost interest in the conversation

Perception of feedback How is feedback interpreted? –Laghing at a sad story => wrong feedback How does perception effect an agents persuasiveness? –Wrong feedback => the speaker becomes diffident and distrustful –The listener is not persuasive, he/she is not paying attention to the conversation

Speaker/Listener Model (1/2) Speaker and listener should not belong to different models –During the same conversation the participants can assume the role either of speaker or listener –The conversation is seen as a loop The speaker should perceive the feedback from the listener and adapt to it –If the listener loses interest the speaker should change the topic of the conversation (or its exposure) in order to re-gain attention –If the speaker does not perceive any feedback from the listener, he/she should investigate if the other participant is paying attention or not.

Speaker/Listener Model (2/2) We aim to implement a model for virtual speaker/listener We will use the tool Greta –Gesture and facial body animation engines Three approaches –Feedback based on input from the user (a processing model is required) –Statistical based model, the feedback does not depend on user input –Wizard of Oz. The feedback is generated by another real person whom the user is not aware of.

Evaluations Two kind of experiments: –Interaction between a real user and Greta in the role of listener –A simulation of a conversation between two virtual ECAs Evaluation of the virtual listener behavior varying possible feedback –Correct feedback (laughing at a joke) –Wrong feedback (crying at a joke)