Dyadic behavioral synchrony between behaviorally inhibited and non-inhibited peers is associated with concordance in EEG frontal Alpha asymmetry and Delta-Beta coupling.

Behavioral synchrony during social interactions is foundational for the development of social relationships. Behavioral inhibition (BI), characterized by wariness to social novelty and increased anxiety, may influence how children engage in moment-to-moment behavioral synchrony. EEG-derived frontal Alpha asymmetry and Delta-Beta coupling reflect approach-avoidance behavior and emotion regulation, respectively. We examined the relation between intradyadic behavioral synchrony in energy levels and peer gaze, BI, and EEG measures (N = 136, 68 dyads, MeanAge = 10.90 years) during unstructured and structured interactions. Energy levels were negatively synchronized when both children exhibited right Alpha asymmetry. If either child exhibited left Alpha asymmetry, the dyad exhibited more positive synchrony. Peer gaze was less synchronized during the unstructured task with left Alpha asymmetry. Greater positive Delta-Beta coupling in BI children was associated with more peer gaze synchrony. Peer gaze was asynchronous when BI children exhibited negative Delta-Beta coupling and their partner exhibited positive coupling.