What is "synchrony"?
An important building block for successful social interaction is synchrony, a state of inter-subject coupling of behavioral and neurobiological activity over time that allows us to have shared representations and shared emotional states with others. This phenomenon of perceptual, attentional, affective, and conceptual alignment with others is facilitated by complex neural circuits that have only begun to be characterized. Until recently, the vast majority of neuroscientific research has focused on single-person approaches, studying individuals in isolation by recording their neural activity during observation of social or non-social stimuli. A paradigm shift has gradually emerged in recent years, moving the field towards “second-person” science, as exemplified by the examination of neural processes during real-time reciprocal social interaction (Redcay & Schilbach, 2019). There has also been an explosion of research on dual-person synchrony in behavior (Davis, Bilms, & Suveg, 2017), affect (Butler, 2015), or peripheral physiology such as hormones or cardiac electrophysiology (Feldman, 2007). Such approaches have revealed novel mechanisms that had not been evident during single-person observations, promising to revolutionize our understanding of human social-cognitive development.