Building Affiliation With Behavioral Mimicry: Personality Characteristics, Physiological Consequences, and Neural Mechanisms

This describes four studies that broadly explore the personality characteristics, physiological consequences, and neural mechanisms underlying the behavioral mimicry that occurs when people try to affiliate with others in social interactions. I address three research questions: (1) which individuals are more likely to mimic in the presence of an affiliation goal, (2) what are the physiological consequences of mimicking to build affiliation, and (3) what is the neural mechanism underlying top-down control of mimicry? Chapter 1 gives background on the causes and consequences of mimicry in social interactions. Chapter 2 asks whether extraverts mimic more than introverts as a way to build rapport. In two studies, participants were either given an affiliation goal or not before interacting with a confederate. Study 1 tested whether extraverts mimicked more than introverts in the presence of an affiliation goal. Study 2 replicated and expanded on the design of study 1 by assessing whether mimicry mediated the relationship between extraversion and rapport (as measured by an independent observer). Study 1 found that extraversion predicts increased mimicry when an affiliation goal is present but not when an affiliation goal is absent. Study 2 showed that mimicry mediates the relationship between extraversion and rapport but only when an affiliation goal is present. These studies show that the rapport-building ability of extraverts emerges only when they are motivated to affiliate, providing evidence for the reward-sensitivity-as-core model of extraversion over the sociability-as-core model of extraversion. Chapter 3 explored the link between psychological, behavioral, and physiological mechanisms involved in affiliation. In study 3, participants were randomly assigned to experience social rejection or social acceptance before they were given either an opportunity to mimic a confederate (face-to-face interaction) or not (interaction behind barrier). Rejected participants (1) mimicked a confederate significantly more than accepted participants and (2) mimicry significantly mediated the effect of social feedback (rejection vs. acceptance) on progesterone change, such that mimicking was associated with increases in progesterone. The results suggest that mimicry facilitates progesterone release, which provides preliminary evidence of a physiological mechanism by which mimicry exerts its psychological effects of increasing affiliation and decreasing psychosocial distress. In Chapter 4, study 4 directly tested two competing hypotheses on the role of the right temporoparietal junction (rTPJ) in top-down control of mimicry. Participants were randomized to receive either active or sham intermittent theta-burst stimulation (a type of stimulation that increases activation) to the rTPJ in a between-subjects design. After receiving either active or sham iTBS, I measured how much participants mimicked another person in a social interaction. The results show that, for participants in the active stimulation condition, hair and face touching was significantly lower during the social interaction compared to baseline. This finding suggests that higher activation in the rTPJ increases the distinction between representations of self and other, specifically biasing representations of self over other, leading to less mimicry. These results do not support the hypothesis that higher activation in the rTPJ leads to flexible control of self-other representations in line with goals. Chapter 5 provides an overview of the main findings of these studies, discusses how these studies inform one another, and points the field toward open questions for future research.