Parent-Reported Toddler Dysregulation and Respiratory Sinus Arrhythmia Predict Trajectories of Childhood Externalizing Behaviors.

Externalizing behaviors (e.g., aggression, oppositionality, conduct problems) typically peak then decrease across early childhood (ages 2-5). However, some children continue to exhibit elevated levels of externalizing behavior throughout childhood, which can have implications for later socioemotional difficulties. Emotion regulation (ER) is an early predictor of continuity in externalizing behaviors. Toddlers with poor ER are more likely to exhibit externalizing behaviors during childhood. Additionally, individual differences in resting autonomic nervous system activity (respiratory sinus arrhythmia; RSA) reflect the capacity for physiological regulation and therefore may moderate associations between early dysregulation and later externalizing behaviors. Therefore, the current study (n = 174) examined the interaction between 18-month toddler behavioral dysregulation and resting RSA in the prediction of externalizing behaviors across early childhood (ages 4-6). Toddlers high in behavioral dysregulation and with lower RSA showed increased levels of externalizing behaviors across early childhood. Toddlers with higher RSA showed decreasing levels of externalizing behaviors across early childhood. These results highlight the importance of using multimethod approaches that capture different dimensions of regulation when examining the role of regulation in externalizing behaviors as the capacity for early physiological regulation may interfere with behavioral regulation to influence the express of later problematic behavior.