Biological Correlates of Parental Engagement on Socioemotional Development in Infancy

Introduction: Infants rely on social cues from their parents to help guide interactions with their external contextual world. One of the biological correlates of the parent-infant relationship is the oxytocin system, which has been shown to play a role in bonding and attachment. Oxytocin may aid in orienting our attention to external social cues, but that it is dependent on individual differences. One such difference may be the oxytocin receptor gene DNA methylation (OXTRm), which aids in regulating endogenous oxytocin use. We hypothesize that parental engagement will help regulate OXTRm, predict neurological processing of social cues, and influence infants’ social-orienting behavior.

Methods: Sixty-four four-month-old infants and their parents underwent a video-recorded free play interaction, which was behaviorally coded for levels of parent engagement and infants’ social-orienting cues. Infants then provided a small saliva sample, which was assayed for OXTRm at site -924; a previously identified site within the oxytocin receptor gene (OXTR) shown to undergo epigenetic modification in response to parental care. Lastly, infants underwent electroencephalography (EEG) while they listened to sounds of running water and infant-directed speech. Event-related potentials were extracted to assess neurological processing of social auditory information.

Results: We found a positive association between parental engagement and OXTRm at site -924. Additionally, we found a strong positive relationship between parental engagement in the form of vocalizations and mood, and infants’ social-orienting behavior. However, we did not find any evidence of neurological correlates of variability in OXTRm, parental engagement, or child behavior.

Discussion: This study further quantifies social behavioral correlates of epigenetic modulation of the oxytocinergic system. While past literature has focused broadly on parental engagement, this study narrows the focus to the effects of parental vocalizations and mood as a potential contributor of OXTRm regulation. Additionally, this study provides further evidence of the importance of parent-infant dyadic relationships on infant socioemotional development beginning as early as 4 months of age.