1.1 Conversation: the Most Natural Means of Communication

Conversation is the most natural and popular means for people to communicate with each other. Conversation is everywhere around us, and even though you may feel that making conversation is relatively effortless, a closer look shows that a tremendous amount of sophisticated interaction is involved in initiating and sustaining conversation. Figure 1.1 illustrates a normal conversation scene in our daily research activities. People use a rich set of nonverbal communication means, such as eye contact, facial expressions, gestures, postures and so on, to coordinate their behaviors and/or give additional meaning to their utterances, as shown in Figures 1.1(a) and (b), where participants are passing the initiative in the discussion from one to the other, or keeping it, by quickly exchanging nonverbal signs such as eye contact and facial expression as well as voice. People are skilled in producing and interpreting these subtle signs in ordinary conversations, enabling them to control the flow of a conversation and express their intentions to achieve their goals. Occasionally, when they get deeply involved in a discussion, they may synchronize their behavior in an almost unconscious fashion, exhibiting empathy with each other. For example, in Figures 1.1(c)–(f), a couple of participants are talking about controlling robots using gestures; they start waving their hands in synchrony to refer to the behavioral modality of a particular gesture. After a while, they become convinced that they have established a common understanding. In addition, their behavior enables the third and fourth participants to comprehend the situation and note it as a critical scene during the meeting. In general, nonverbal means of communication play an important role in forming and maintaining collaborative behaviors in real time, contributing to enhancing engagement in conversation. The process normally takes a short period of time and is carried out almost unconsciously in daily situations. Nonverbal interaction makes up a significant proportion of human–human interactions (Kendon 2004). Some authors consider that nonverbal interaction reflects intentions at a deeper level and precedes verbal communication in forming and maintaining intentions at the verbal level. McNeill suggests that verbal and nonverbal expressions occur in parallel for some psychological entities called growth points (McNeill 2005). Conversations consisting of verbal and nonverbal interactions not only provide the most natural means of communication but also facilitate knowledge creation through such mechanisms as heuristic production