Researchers in Belgium have compared the physiological response of babies to mothers and fathers stroking them, which is part of the bonding process. They found no differences. This, say the researchers, mitigates the doubts about fathers’ capabilities for bonding with their infants during the first weeks of life.

When filmed, mothers and fathers both stroked their babies at a rate and in places known to stimulate the most positive response in the baby. There is a group of nerves called ‘c-tactile afferents’ that are found in hairy skin (arms, legs, shoulders, head) and these respond optimally to stroking between 1 and 10 cm/second.

The physiological response of the babies to stroking was the same for mothers and fathers, both during the stroking and in the minutes after. The researchers measured the ‘respiratory sinus arrhythmia’ (RSA). This is the amount that the heartbeat changes between breathing in and breathing out and an increase is a positive physiological response of regulation, reflecting one’s flexibility to cope with stress. This flexibility needs to be built during bonding and is thus part of the development of well-functioning stress-regulation in the baby.

There was one difference between mothers and fathers. Breathing decreased during stroking with mothers on average more than for fathers, though after the stroking, the rates converged. So other physiological responses of the baby were the same for fathers at higher levels of arousal on the part of the baby.

The experiment involved 25 mothers and 25 (unrelated) fathers of babies aged 4 to 16 weeks and took place in Brussels, Belgium. The parent was asked to stroke the baby in any way they wanted for 3 periods of one minute, separated by 10 seconds. The parents were videoed doing this and at the same time, the baby’s heartbeat and breathing were measured.

Van Puyvelde M, Collette L, Gorissen , Pattyn N & McGlone F (2019), Infants autonomic cardio-respiratory responses to nurturing stroking touch delivered by the mother or the father, Frontiers in Physiology 10

Header photo: Bridget Coila. Creative Commons.