Inter-Brain Synchrony during Lived and Invoked Social Moments

Abstract Inter-brain synchrony has recently emerged as a key mechanism of brain development and functioning. Two perspectives on neural synchrony have differentially measured cross-brain coordination during active participation in social moments versus passive observation of social stimuli, but the integration of the two processes is still unknown. Guided by the biobehavioral synchrony frame, we utilized hyperscanning EEG and a novel paradigm to shed light on the linkage between inter-brain synchrony during lived and invoked social experiences. In Study 1 (n = 130) mother-adolescent dyads engaged in free interaction, coded for behavioral synchrony, and then observed this interaction in separate rooms. Greater neural synchrony across the fronto-temporal inter-brain network emerged during active participation than passive observation, and the two were inter-related and predicted by behavioral synchrony. Study 2 (n = 54) tested the generalizability of the findings in unfamiliar adults and similarly found linkage between neural synchrony during live and invoked experiences, both associated with behavioral synchrony. Results demonstrate that shared social experiences create lasting neural synchrony that can be reactivated during subsequent invocation and depends on relationship quality and familiarity. Our findings bear important implications for the role of lived social moments and their retention in memory in shaping the social brain.