Donate or receive? Social hyperscanning application with fNIRS

Recent research in social neuroscience has shown how prosocial behavior can increase perceived self-efficacy, perception of cognitive abilitites and social interactions. The present research explored the effect of prosocial behavior, that is giving a gift during an interpersonal exchange, measuring the hyperscanning among two brains. The experiment aimed to analyze the behavioral performance and the brain-to-brain prefrontal neural activity of 16 dyads during a joint action consisting in a cooperative game, which took place in a laboratory setting controlled by an experimenter, to play before and after a gift exchange. Two different types of gift exchange were compared: experiential and material. Functional Near Infrared Spectroscopy (fNIRS) was applied to record brain activity. Inter-brain connectivity was calculated before and after the gift exchange. In behavioral data, a behavioral performance increase was observed after gift exchange, with accuracy improvement and response times decrease. Regarding intra-brain analyses, an increase in oxygenated hemoglobin was detected, especially in the dorsolateral prefrontal cortex (DLPFC) in both donor and receiver; and in the dorsal part of the premotor cortex (DPMC) in the donor. Moreover, as regards the gift type, greater activation in the DPLFC emerged in both the donor and the receiver after receiving an experiential gift. Finally, the results of the inter-brain connectivity analysis showed that after gift exchange, the donor and receiver brain activity was more synchronized in the DPMC and Frontal Eye Fields (FEF) areas. The present study provides a contribution to the identification of inter-brain functional connectivity when prosocial behaviors are played out.