Mutual influence of nonverbal behavior in interpersonal communication

In social interactions, the interactants' nonverbal behavior may synchronize and become similar. In this study, the author called this phenomenon ‘synchrony tendency’. Since conventional research about this phenomenon has been conducted from various angles separately, there has been almost no attempt to examine the role of synchrony tendency systematically. In this light, the present study aims at reviewing synchrony tendency based on previous studies from various fields and perspectives. The synchrony tendency has been observed in various communication channels, and in various forms, such as interspeaker congruence of paralanguage, convergence of accents in cross-cultural communication, mimicry of other’s facial and vocal emotional expressions, neonate imitation, interpersonal synchrony of body movements, entrainment between a neonate's body movement and the flow of an adult's speech. Therefore, this phenomenon has been labeled with various terms, each one having a specific nuance. Moreover, the synchrony tendency is not always observed in all interactions, and it sensitively changes with various factors, such as the interactants' level of empathy and socialization. For example, the results of my experiments indicate that the convergence of response latencies (i.e., latencies before responding to the last utterance of one's partner) in dialogues reflects whether a speaker is receptive to the conversational partner during the dialogue. All these suggest that the synchrony tendency provides an effective indicator reflecting various aspects of our communication behavior. Various functions of the synchrony tendency in adults’ interactions can be inferred from past literature: (a) it facilitates the understanding of an interactional partner's emotions, (b) it conveys empathy and rapport, and (c) it makes the speakers' personality and attitude feel positive. Furthermore, the results of my experiments showed that the synchrony tendency facilitates goal achievement, such as reaching a compromise through discussion (the speakers whose response latencies became similar over the time course to those of their conversational partners evaluated that they reached a compromise). Past literature along with the results of my own experiments bring to light two aspects of the synchrony tendency: the emotional/automatic/inherent aspect and the cognitive/acquired aspect. Examples that clearly illustrate the former aspect are imitations of facial and vocal emotional expressions and neonate imitation. On the other hand, the cognitive/acquired aspect is illustrated by convergence or congruence of response latencies, vocal intensity, speech duration, language, or accent, and is influenced by social factors. The above-mentioned aspects of the synchrony tendency match Hess, Philippot, & Blairy (1999)’s mimicry model, Giles et al.’s communication accommodation theory (ex. Shepard, Giles, & LePoire, 2001), as well as the author’s speech style convergence model. The speech styles convergence model derived from a series of studies on the convergence of response latencies in dialogues. This model suggests that adopting a partner’s speech style and the output cycle between the interactants being influenced by the speakers’ social skills and attitude towards the partner, this cycle develops over the course of the interaction until the speech styles finally converge to a point most suitable for the members of the dyad to progress smoothly through the dialogue. In the future, it is necessary to investigate quantitatively through which communication channels, and when in the time course of an interaction, the synchrony tendency is displayed.