Effects of human contact and vagal regulation on pain reactivity and visual attention in newborns.

In two experiments we examined the effects of human contact and vagal regulation on newborns' pain reactivity and visual attention. Baseline cardiac vagal tone was measured during quiet sleep and during the experiment, and vagal withdrawal was indexed as change in vagal tone from baseline to pain (study 1) or attention (study 2). In study 1, 62 healthy newborns were videotaped during a heel-prick procedure and pain reactivity was assessed from micro-level coding of facial expressions, cry behavior, and body movements. Infants were randomly assigned to a contact condition, held by a female assistant, or a no contact condition, on an infant-seat in a similar angle. In study 2, 62 additional healthy newborns, randomly assigned to contact and noncontact conditions, were presented with 2 visual stimuli for a 60 s familiarization period, which were then paired with a novel stimulus. Visual interest, alertness, and novelty preference were coded. Human contact had no effect on the newborns' pain response. Visual attention increased with human contact and newborns in the contact condition looked at the stimuli more frequently, with higher alertness, for longer durations, and had a higher novelty preference. Autonomic reactivity-as indexed by vagal withdrawal-differentiated newborns with intense and mild pain response. Discussion focused on proximity to conspecifics as a contributor to emerging regulatory and adaptive functioning in the human infant.