Form and Function in Motor Mimicry Topographic Evidence that the Primary Function Is Communicative

Motor mimicry is behavior by an observer that is appropriate to the situation of the other person, for example, wincing at the other's injury or ducking when the other does. Traditional theories of motor mimicry view this behavior as an indicator of a vicarious cognitive or empathic experience, that is, of taking the role of the other or of “feeling oneself into” the other person. However, Bavelas, Black, Lemery, and Mullett (1986) have shown that motor mimicry of pain is affected by communicative variables and acts as a nonverbal message indicating that the observer is aware of and concerned about the other's situation. This raises a more general question: Is communication its primary or secondary function? We propose (i) that motor mimicry functions as a nonverbal, analogic, relationship message about similarity between observer and other and (ii) that this message is encoded according to Gestalt principles of form, in that the observer physically mirrors the other. In other words, the observer maintains a relationship with the other. The special case of left/right leaning when observer and other are facing each other permits a test of our theory against two theories that treat motor mimicry as an indicator of vicarious experience. The results of three experiments showed that when motor mimicry by an observer facing someone who is leaning left or right occurs, it is both displayed and decoded in the form consistent with a communication theory; this form is called reflection symmetry. We conclude that, because of the topography of the response, the primary function of motor mimicry must be communicative and that any relationship to vicarious processes is secondary. A similar analysis of other nonverbal behaviors may well reveal that they are also expressions to another person rather than expressions of infrapsychic states.