Cooperation forms the basis of our society and becomes increasingly essential during times of globalization. However, despite technological developments people still prefer to meet face-to-face,... Show moreCooperation forms the basis of our society and becomes increasingly essential during times of globalization. However, despite technological developments people still prefer to meet face-to-face, which has been shown to foster cooperation. However, what is still unclear is how this beneficial effect depends on what people know about their interaction partner. To examine this question, 58 dyads played an iterated Prisoner’s Dilemma game, sometimes facing each other, sometimes without face contact. Additionally, explicit feedback regarding their decisions was manipulated between dyads. The results revealed that participants were more cooperative when they saw each other compared to when they could not, and when receiving reliable compared to unreliable or no feedback. Contradicting our hypothesis that participants would rely more on nonverbal communication in the absence of explicit information, we observed that the two sources of information operated independently on cooperative behavior. Interestingly, although individuals mostly relied on explicit information if available, participants still cooperated more after their partner defected with face-to-face contact compared to no face-to-face contact. The results of our study have implications for real-life interactions, suggesting that face-to-face contact has beneficial effects on prosocial behavior even if people cannot verify whether their selfless acts are being reciprocated. Show less
Humans attend to others’ facial expressions and body language to better understand their emotions and predict goals and intentions. The eyes and its pupils reveal important social information.... Show moreHumans attend to others’ facial expressions and body language to better understand their emotions and predict goals and intentions. The eyes and its pupils reveal important social information. Because pupil size is beyond voluntary control yet reflective of a range of cognitive and affective processes, pupils in principal have the potential to convey whether others’ actions are interpreted correctly or not. Here, we measured pupil size while participants observed video-clips showing reach-to-grasp arm movements. Expressors in the video-clips were playing a board game and moved a dowel to a new position. Participants’ task was to decide whether the dowel was repositioned with the intention to be followed up by another move of the same expressor (personal intention) or whether the arm movement carried the implicit message that expressor’s turn was over (social intention). Replicating earlier findings, results showed that participants recognized expressors’ intentions on the basis of their arm kinematics. Results further showed that participants’ pupil size was larger when observing actions reflecting personal compared to social intentions. Most interestingly, before participants indicated how they interpreted the observed actions by choosing to press one of two keys (corresponding to the personal or social intention), their pupils within a split second, had already given away how they interpreted the expressor’s movement. In sum, this study underscores the importance of nonverbal behavior in helping social messages get across quickly. Revealing how actions are interpreted, pupils may provide additional feedback for effective social interactions. Show less
