Pupil mimicry promotes trust through the theory-of-mind network

Abstract

The human eye can provide powerful insights into the emotions and intentions of others; however, how pupillary changes influence observers' behavior remains largely unknown. The present fMRI-pupillometry study revealed that when the pupils of interacting partners synchronously dilate, trust is promoted, which suggests that pupil mimicry affiliates people. Here we provide evidence that pupil mimicry modulates trust decisions through the activation of the theory-of-mind network (precuneus, temporo-parietal junction, superior temporal sulcus, and medial prefrontal cortex). This network was recruited during pupil-dilation mimicry compared with interactions without mimicry or compared with pupil-constriction mimicry. Furthermore, the level of theory-of-mind engagement was proportional to individual's susceptibility to pupil-dilation mimicry. These data reveal a fundamental mechanism by which an individual's pupils trigger neurophysiological responses within an observer: when interacting partners synchronously dilate their pupils, humans come to feel reflections of the inner states of others, which fosters trust formation.

The neuroethology of spontaneous mimicry and emotional contagion in human and non-human animals

“…For example, Harrison and colleagues (Harrison et al, 2006) found that pupil contagion, besides brainstem pupillary control nuclei, also recruits other cortical and subcortical regions implicated in social cognition and Theory of Mind (ToM), such as STS, amygdala, frontal operculum and intraparietal sulcus. Moreover, when pupils of interacting partners synchronously dilate, trust decisions are promoted through the activation of ToM network including the precuneus, the temporo-parietal junction (TPJ), STS, and mPFC (Prochazkova et al, 2018). These and other similar data support the contention that pupil size influences the vicarious understanding of expressed emotions and affords an evolutionary ancient neurophysiological mechanism that is active across the primate lineage to promote affiliation, bonding, and trust through mimicry (Carsten et al, 2018;Kret, 2015;Kret and De Dreu, 2017).…”

Cerebral responses to self-initiated action during social interactions

“…Importantly, the precuneus, AG and ITG responded to selfinitiated actions to a greater extent in EX compared with FG. These brain regions were commonly engaged during theory of mind and social emotional processing (Prochazkova et al, 2018;Thye, Ammons, Murdaugh, & Kana, 2018;Tsoi, Dungan, Chakroff, & Young, 2018), as well as during self- Fig. 4 Correlation of regional responses to self-agency to behavioral performance.…”

Quantifying Physiological Synchrony through Windowed Cross-Correlation Analysis: Statistical and Theoretical Considerations

“…During social interactions, humans tend to synchronize on different levels: They mimic postures (Ramseyer & Tschacher, 2011), facial expressions (Chartrand & Bargh, 1999) and align their level of physiological arousal (Feldman, Magori-Cohen, Galili, Singer, & Louzoun, 2011;Levenson & Gottman, 1983;Prochazkova et al, 2018). Although this synchrony comes naturally and without effort, it is a great challenge for social scientists to measure it statistically.…”

“…Synchrony is a multifaceted phenomenon evident on the behavioral, physiological, and neural level. Not surprising then, the causes and consequences of synchrony have been studied in a broad range of contexts investigating the dynamic nature of social interactions from clinical (Galazka et al, 2019;Wehebrink, Koelkebeck, Piest, De Dreu, & Kret, 2018), developmental (de Klerk, Hamilton, & Southgate, 2018;Shih, Quiñones-Camacho, Karan, & Davis, 2019), evolutionary (Mancini, Ferrari, & Palagi, 2013;Palagi, Leone, Mancini, & Ferrari, 2009), neural (Hasson, Nir, Levy, Fuhrmann, & Malach, 2004;Prochazkova et al, 2018), social (Behrens et al, 2019;Tarr, Launay, & Dunbar, 2016), and cognitive (Kret, Fischer, & De Dreu, 2015;Kret & De Dreu, 2017) perspectives. Such fascination across disciplines has unraveled the far-reaching scope of synchrony: it has been demonstrated in different species, it occurs from birth on, and it influences a variety of interpersonal processes such as marital quality, cooperative success between strangers and outcomes of therapeutic interactions (Behrens et al, 2019;Feldman et al, 2011;Kret, Tomonaga, & Matsuzawa, 2014;Levenson & Gottman, 1983;Ramseyer & Tschacher, 2011).…”