Paternal oxytocin levels moderate father-infant touch dynamics during triadic family interaction.

Touch is a fundamental mode of communication and bonding between parents and infants. While oxytocin, a neuropeptide known for promoting social bonding and regulating responsiveness, is implicated in these processes, most research has focused on mothers in dyadic settings. This leaves a significant gap in understanding fathers' roles and the complex dynamics within triadic family interactions. This study addresses this by examining the real-time interplay between parental touch, infant affect, and parental oxytocin levels in a three-person family context.

This observational study involved 69 families from a longitudinal cohort, observed during a four-minute triadic free-play task when infants were six months old (M = 28.7 weeks, SD = 2.3 weeks). Parental touch and infant affect were micro-coded second-by-second using the Triadic Coding System. Plasma oxytocin was assayed from parental blood samples taken after the interaction. Dynamic Structural Equation Modeling (DSEM) was employed to analyze time-lagged associations between infant affect and parental touch, and to determine if these links were moderated by parental oxytocin levels.

Both mothers and fathers exhibited strong moment-to-moment stability in their touch intensity. A significant bidirectional association was observed between parental touch and infant positive affect across time, establishing a positive feedback loop. Crucially, paternal post-interaction plasma oxytocin moderated these dynamics. Fathers who responded to infant positive affect with more vigorous touch displayed higher oxytocin levels. No such moderation was found for maternal oxytocin levels. > These results were specifically evident when analyzing extracted oxytocin, which is considered the gold standard for reliability, underscoring the robustness of the paternal oxytocin finding. The study highlights the intricate, real-time coordination within family interactions.