Emotional Reactivity and Internalizing Symptoms in Middle Childhood: Integrating Autonomic and Behavioral Markers of Social Fear and Positive Affect.

Emotional reactivity is a well-validated corollary of children's risk for internalizing psychopathology and can be indexed by autonomic and behavioral measures. Yet, it is unclear whether and how autonomic and behavioral markers of emotional reactivity interact to characterize internalizing symptoms and whether these associations differ based on emotional context. As such, the current study aimed to (1) clarify associations between autonomic (RSA, PEP) and behavioral measures of emotional reactivity across two tasks designed to elicit fear and positive affect in social contexts and (2) examine the unique and combined associations between autonomic and behavioral reactivity during these tasks and internalizing symptoms. Participants were 328 children aged 6-10 (M = 7.91, SD = 0.97; 50% female; 94% White). Behavioral displays of positive affect during a parent task were associated with RSA withdrawal, but there were no significant associations between autonomic reactivity and behavioral displays of stranger fear. RSA augmentation during the parent task was associated with lower internalizing symptoms at average or high levels of positive affect. Finally, higher stranger fear was associated with higher internalizing symptoms only when coupled with reciprocal parasympathetic activation. These findings suggest context-specific patterns of autonomic activation that are differentially associated with internalizing symptoms.