Sjak-Shie, E. E. | Search bioRxiv

bioRxiv2019

Physiological synchrony promotes cooperative success in real-life interactions

Cooperation is pivotal for society to flourish and prosper. To ease cooperation, humans express and read emotions and intentions via explicit signals or subtle reflections of arousal visible in the face. Evidence is accumulating that humans synchronize these nonverbal expressions, as well as the physiological mechanisms underlying them, potentially promoting cooperative behavior. The current study is designed to verify the existence of this putative linkage between synchrony and cooperation. To that extent, 152 participants played multiple rounds of the Prisoners Dilemma game in a naturalistic dyadic interaction setting. During one round of games they could see each other, and during a second round they could not. The results showed that when peoples heart rate and skin conductance level aligned, they cooperated more successfully. Interestingly, for skin conductance level synchrony to boost cooperation, face to face contact was essential. The effect of heart rate synchrony on cooperation was context independent. Skin conductance level, but not heart rate, tended to closely correlate with changes in pupil size and we discuss how the pupil might provide a window to partners sympathetic arousal. These findings show how unconscious mechanisms guide social behavior and emphasize the importance of studying social processes between rather than within individuals in real-life interactions. Significance StatementHuman cooperation is remarkable in its scale, complexity, and efficiency. However, whereas people think of themselves as rational agents, they actually partly base their decision to cooperate with someone on gut feelings. These feelings are informed by non-verbal expressions that are picked up implicitly and that synchronize across interaction partners. For the first time, we show that the alignment of peoples arousal over multiple rounds of the Prisoners dilemma game predicts cooperative success. Through synchrony, partners converge emotionally, fostering understanding and bonding, which are key ingredients when it comes to successful cooperation. This suggests that successfully cooperating does not depend on individuals, but on the connection between individuals, emphasizing the importance of studying social decision-making processes in real-life settings.

physiology↗

bioRxiv2019

The choreography of human attraction: physiological synchrony in a blind date setting

Humans are social animals whose mental wellbeing is shaped by the ability to attract and connect with each other. In a dating world, in which success can be determined by brief interactions, apart from physical features, there is a whole choreography of movements, physical reactions and subtle expressions that drive humans sexual attraction. To determine what drives attraction, we measured nonverbal dynamics between people during real-life interactions outside the laboratory, where dating is most relevant. Participants wore eye-tracking glasses with embedded cameras, and devices to measure physiological signals including heart rate and skin conductance. Crucially, visible signals that can be controlled, such as facial expressions or gaze, did not predict attraction. Instead, attraction was predicted by synchrony in heart rate and skin conductance between partners, which are unconscious and difficult to regulate. Our findings suggest that shared emotionality is vital for mutual attraction. Moreover, physiological synchrony may provide a medium for translating visible expressions into embodied emotions, which can turn into intentions via somatosensory simulation. Significance StatementIn our modern world where millions of people meet online without interacting face-to-face, the question "what defines attraction" has become very relevant. In this study, we used modern technologies to lay down a foundation for the processes that drive human attraction during real-life interactions. Contrary to common belief, we found that attraction is not predicted by a frequency of expression or eye fixation duration, nor is linearly related to the participants autonomic nervous system activity. Importantly, we found that the more a participant synchronized their heart rate and skin conductance with their partner, the more they felt attracted toward that person. This study reveals a fundamental physiological process that plays a role in the formation of romantic relations.

physiology↗