The association between parasympathetic reactivity and children’s prosocial behavior: The moderating role of parental response to children’s negative emotions

The present study examined the relationship between physiological regulation (indexed by resting RSA and RSA reactivity) and children's prosocial behaviors as well as the potential moderating role of parental responses to children's negative emotions. A total of 108 children (ages 7–13 years; M = 10.00, SD = 1.37; 61 males) completed the Trier Social Stress Task–Child version (TSST-C), during which Respiratory Sinus Arrhythmia (RSA) was measured, along with self-report measures of prosocial tendencies and perceptions of parental emotion responses. The results revealed no significant linear or quadratic associations between resting RSA or RSA reactivity and prosocial behavior. However, nonparental responses significantly moderated the linear relationship between RSA reactivity during the math component of the TSST-C and prosocial behavior. Specifically, children who exhibited RSA withdrawal to the math task showed higher levels of prosocial behavior than those with blunted RSA or RSA augmentation, when they perceived low levels of nonparental support (e.g., dismissiveness or punitive reactions). However, under supportive conditions characterized by expressive encouragement, problem-focused, or emotion-focused responses, a similar pattern did not emerge. Furthermore, no moderating effects were found for the quadratic relationship between RSA reactivity and prosocial behavior. These findings tentatively suggest a combined influence of children's physiological stress responses and family emotion socialization on prosocial development, potentially reflecting context-dependent processes. • No significant linear or quadratic associations between resting RSA/RSA reactivity and prosocial behavior. • RSA augmentation linked to reduced prosocial behavior in children perceiving low parental support. • RSA withdrawal associated with increased prosocial behavior under high nonsupportive parenting (e.g., punitive reactions).