Parent conflict predicts infants' vagal regulation in social interaction.

Parent conflict during infancy may affect rapidly developing physiological regulation. To examine the association between parent conflict and infants' vagal tone functioning, mothers (N = 48) reported levels of parent conflict and their 6-month-old male and female infants' respiratory sinus arrhythmia (RSA) was measured in the still-face paradigm. Higher parent conflict was related to lower RSA at baseline and each episode of the still-face paradigm. Infants in relatively higher conflict families showed attenuated RSA withdrawal in response to mothers' disengagement and attenuated RSA activation when interacting with mothers. Findings suggest atypical RSA regulation and reliance on self-regulation for infants in families with moderate levels of parent conflict. Implications for later development and future research are discussed.