Maternal capitalization support is associated with children's basal respiratory sinus arrhythmia.

Positive responses to capitalization, the process of sharing positive experiences and emotions, are associated with better relationship wellbeing and consequently health and adjustment in the context of romantic relationships. However, responses to capitalization have rarely been studied in parent-child dyads, whereas most of the research has focused on how parents respond to children's negative emotions. The current study tested associations between maternal positive emotion socialization, specifically capitalization support and children's adaptive regulatory capacity indexed by baseline respiratory sinus arrhythmia (RSA). Ninety children (M_age = 41.87 months, SD = 4.29; 47.8% boys) participated in the study. Capitalization support indexed by maternal active-constructive responses during a conversation was observed and coded. Children's basal RSA levels when watching a calming video were assessed. Mothers also reported their reactions to children's negative emotions, child temperament and relationship closeness. Maternal capitalization support was associated with children's higher basal RSA levels, independent of maternal supportive reactions to children's negative emotions, child negative affect, and relationship closeness. The implication that supportive socialization for positive emotions benefits children's physiological regulation above and beyond that for negative emotions was discussed.