title: Pupil Mimicry Correlates With Trust in In-Group Partners With Dilating Pupils.
abstract: During close interactions with fellow group members, humans look into one another's eyes, follow gaze, and quickly grasp emotion signals. The eye-catching morphology of human eyes, with unique eye whites, draws attention to the middle part, to the pupils, and their autonomic changes, which signal arousal, cognitive load, and interest (including social interest). Here, we examined whether and how these changes in a partner's pupils are processed and how they affect the partner's trustworthiness. Participants played incentivized trust games with virtual partners, whose pupils dilated, remained static, or constricted. Results showed that (a) participants trusted partners with dilating pupils and withheld trust from partners with constricting pupils, (b) participants' pupils mimicked changes in their partners' pupils, and (c) dilation mimicry predicted trust in in-group partners, whereas constriction mimicry did not. We suggest that pupil-contingent trust is in-group bounded and possibly evolved in and because of group life.
authors.affiliation: Psychology Department, University of Amsterdam Amsterdam Brain and Cognition Center, University of Amsterdam m.e.kret@umail.leidenuniv.nl.
authors.forename: M E
authors.initials: ME
authors.lastname: Kret
authors.affiliation: Psychology Department, University of Amsterdam Amsterdam Brain and Cognition Center, University of Amsterdam.
authors.forename: A H
authors.initials: AH
authors.lastname: Fischer
authors.affiliation: Psychology Department, University of Amsterdam Amsterdam Brain and Cognition Center, University of Amsterdam Center for Experimental Economics and Political Decision Making, University of Amsterdam.
authors.forename: C K W
authors.initials: CK
authors.lastname: De Dreu
mesh_terms: D003299:Cooperative Behavior; D004644:Emotions; D005260:Female; D006801:Humans; D008297:Male; D011680:Pupil; D012044:Regression Analysis; D056345:Theory of Mind; D035502:Trust / Q000523:psychology*
keywords: contagion; cooperation; emotion; groups; theory of mind