Inter-brain synchrony during interpersonal touch is associated with the remission of negative emotion

Interpersonal touch plays an essential role in emotional regulation. However, the mechanisms underpinning emotional regulation via interpersonal touch remain obscure. This study investigated inter-brain synchrony (IBS) during the evaluation of affective images in the context of interpersonal touch, and examined the role of IBS in alleviating negative emotional responses. We recruited 47 dyads (N=94) female participants. Each dyads participant viewed affective images (negative and neutral valence) and evaluated their valence and arousal during touch and no touch. During the task, their neural activities in the prefrontal regions were recorded using functional Near-Infrared Spectroscopy (fNIRS)-based hyper-scanning. Our results demonstrated that interpersonal touch buffers individuals’ experience of negative emotions and increases IBS. Furthermore, the IBS mediated the association between interpersonal touch and the arousal scores of negative stimuli. Thus, we concluded that IBS may represent an underlying neural mechanism of the regulation of negative emotion between the touch sender and receiver. Notably, in friend, IBS was a positive predictor of friendship quality. Future studies may uncover whether inter-brain synchrony can serve as a neurobiological marker of the dyad's emotional regulation, and can be modified by touch interventions.