Dyadic Social Dynamics in Separation-Related Anxiety: Multimodal Arousal Synchrony Between 4-Year-Olds and Their Mothers

Separation anxiety disorder (SAD) is an early-onset disorder linked to adverse outcomes into adulthood. To advance SAD etiology, this study examined how parental risk factors relate to dyadic social dynamics. Seventy-two four-year-olds (50% girls, 93% primarily German-speaking) and their mothers (74% holding a Bachelor’s degree) participated in a standardized separation paradigm. Parental reports, heart rate, and machine-learning-based measures of facial and vocal arousal were assessed. The announcement of separation increased children’s physiological (ꞵ=.17) and vocal arousal (ꞵ=.13). Within individuals, physiological and vocal arousal were coordinated (r=.18–.20), while across dyads, facial (r=.15) and vocal arousal (r=.09) showed consistent synchrony. Physiological synchrony emerged selectively in dyads with higher maternal anxiety (r=.31) but was unrelated to absolute arousal or SAD symptoms. Anticipatory physiological synchrony was negatively associated with child vocal arousal during separation (r=-.44). Early separation-related anxiety appears embedded in dyadic processes, shaped by vocal arousal transmission and maternal anxiety symptoms.