Group decision-making behavior in social dilemmas: Inter-brain synchrony and the predictive role of personality traits

There are currently many studies available on individual decision-making (hereafter IDM) behavior; however, there are fewer that investigate how inter-brain social influences are substantiated in group decision-making behavior (hereafter GDM). This study examines the neural substrate of GDM and how an individual's personality affects the inter-brain synchrony of GDM in an economic social interaction situation. We used a functional near-infrared spectroscopy (fNIRS) hyperscanning system to simultaneously measure pairs of participants' inter-brain synchrony in a GDM game. The fNIRS results showed significant differences in inter-brain synchrony between IDM and GDM. Furthermore, agreeableness as a personality trait seems to be a predictive factor of inter-brain synchrony in GDM, and GDM is also influenced by the combination effect of personality and situation context. This investigation of inter-brain synchrony during group decision-making behavior improves not only our understanding of the neural substrate of group decision-making behavior and the association between personality traits and the neural network underlying GDM, but more generally contributes knowledge to the growing field of social neuroscience and neuroeconomics.