Non-verbal Persuasion and Communication in an Affective Agent

This chapter deals with the communication of persuasion. Only a small percentage of communication involves words: as the old saying goes, “it’s not what you say, it’s how you say it”. While this likely underestimates the importance of good verbal persuasion techniques, it is accurate in underlining the critical role of non-verbal behaviour during face-to-face communication. In this chapter we restrict the discussion to body language. We also consider embodied virtual agents. As is the case with humans, there are a number of fundamental factors to be considered when constructing persuasive agents. In particular, one who wishes to persuade must appear credible, trustworthy, confident, and non-threatening. Knowing how not to behave is also a vital basis for effective persuasion. This includes resolving task constraints or other factors with the social perception considerations. These social virtual agents face many of the same problems as humans have in controlling and expressing themselves in an appropriate manner so as to establish and maintain persuasive interaction. All along the chapter, much of our discussion will handle concepts applicable both to agent and to human behaviour.