Interaction Crucial to Development of Infant Hormone System

All parents know that interacting and playing with their young children brings benefit, aiding both cognitive development and the parent-child bond. However, the benefits of such interactions are even more profound than we knew, with a new study finding that by taking time to interact with their babies, parents can help develop the infant hormone system.

The University of Virginia study of 101 babies, which was led by Kathleen Krol, found that children who receive more tactile and verbal interaction appear to develop increased numbers of oxytocin receptors during their first 18 months of life.

Oxytocin, often described as the “love hormone”, is produced by the hypothalamus and released by the posterior pituitary. It is known to play an important role in childbirth, parent-child bonding, breastfeeding, sexual reproduction, social bonding and, in particular, the postnatal period. Furthermore, its role is not confined to humans; oxytocin is important to the development and relationships of all mammals.

The study began looking at 101 children from the age of five months, making detailed observations of the mother-child interaction during five-minute sessions in which mother and child were left alone with toys and a book. Each interaction was then scored for mother-baby closeness, the mother’s responsiveness to any infant distress, the level of eye contact as well as various other factors. The observation session was then repeated once the child had reached 18 months of age.

Oxytocin was measured at both the five-month and 18-month session, with the scientists taking DNA samples from both mother and child in order to examine the gene that codes for the oxytocin receptor. All epigenetic (post-birth) changes to this gene were noted, with the researchers particularly keen to examine changes to the methyl group on the gene, with those genes that were methylated assumed to be “turned off”.

The scientists found that although the mothers’ oxytocin levels remained constant across the two sessions, their children’s were altered, with the those who received more interaction having reduced levels of methylation; conversely, those who received less interaction had increased levels of methylation.

The scientific world is only just beginning to properly explore the roles of hormones in social, cognitive and neuropsychological development, but this new study indicates that babies who receive more interaction develop more oxytocin receptors, enabling them to build better resilience to frustration and environmental extremes such as strong lights and unfamiliar textures.

Furthermore, the scientists believe that their findings most likely extend to father-child as well as mother-child interactions – indeed it is likely that attention from other caregivers may prove just as crucial. “We have no reason to believe this is specific to mothers,” said Krol. “My hypothesis would be that the behaviour of the father and other important caregivers is also influencing this system.”

Practical implications for parents and other caregivers

Although the study’s findings are not conclusive – they only examined a single region on one gene – we think it is safe to offer the following guidance: interact, interact, interact.

Touch, speech, play and eye contact are all essential to fostering most human relationships so it stands to reason that these things play a crucial role in the most formative years.

Touch and talking most certainly don’t require a manual; however, in today’s world of touchscreen devices it can be difficult to keep the essential human habits that underpin parent-child bonding. If necessary, turn your phone off, put it somewhere out of the way and just hang out with your child.