Proximity and Touch are associated with Neural but not Physiological Synchrony in Naturalistic Mother-Infant Interactions

Abstract

AbstractCaregiver touch plays a vital role in infants’ growth and development, but its role as a communicative signal in human parent-infant interactions is surprisingly poorly understood. Here, we assessed whether touch and proximity in caregiver-infant dyads are related to neural and physiological synchrony. We simultaneously measured brain activity and respiratory sinus arrhythmia of 4- to 6-month-old infants and their mothers (N=69 dyads) in distal and proximal joint watching conditions as well as in an interactive face-to-face condition. Neural synchrony was higher during the proximal than during the distal joint watching conditions, and even higher during the face-to-face interaction. Physiological synchrony was highest during the face-to-face interaction and lower in both joint watching conditions, irrespective of proximity. Maternal affectionate touch during the face-to-face interaction was positively related to neural but not physiological synchrony. This is the first evidence that touch mediates mutual attunement of brain activities, but not cardio-respiratory rhythms in caregiver-infant dyads during naturalistic interactions. Our results also suggest that neural synchrony serves as a biological pathway of how social touch plays into infant development and how this pathway could be utilized to support infant learning and social bonding.HighlightsMother-infant neural and physiological synchrony arise during mutual engagement.Behavioral correlates of neural and physiological synchrony diverge.Interpersonal neural synchrony is related to proximity and affective touch.Interpersonal physiological synchrony is related to infant negative affect.