The behaviour of parents may influence their children's developing system of oxytocin -- a hormone involved in social interaction and bonding in mammals -- according to a study that highlights the importance of parenting in infant health.
The researchers, including those from the Max Planck Institute for Human Cognitive and Brain Sciences in Germany, observed a free play interaction between 101 mothers and their five-month-old children. They collected saliva samples from both the mother and the infant, and then a year later, when the child was 18 months old to quantify the oxytocin levels.
The study, published in the journal Science Advances, noted that greater involvement by mothers during the play interaction may have the potential to upregulate the oxytocin system in their kids. The hormone oxytocin is actively involved in early social, perceptual, and cognitive processes, and it influences complex social behaviours, the study noted.
The researchers said that some cells in the body reacted to oxytocin through the oxytocin receptors present on their surfaces, and the genes involved in producing these receptors were essential for the hormone's effects to take hold. "The oxytocin receptor is essential for the hormone oxytocin to exert its effects and the gene can determine how many are produced," said study co-author Kathleen Krol from the University of Virginia in the US.
Krol said that the quality of a mother's involvement during the play session was linked to chemical changes in the production of the infant's oxytocin receptor gene. She said that chemical modifications called DNA methylation undergone by the receptor genes were determined by the quality of the mother's involvement during play sessions.
"If mothers were particularly involved in the game with their children, there was a greater reduction in DNA methylation of the oxytocin receptor gene one year later. Decreased DNA methylation in this region has previously been associated with increased expression of the oxytocin receptor gene," Krol said.
The study noted that greater maternal involvement during play sessions may boost the oxytocin system in children.
"Importantly, we also found that the DNA methylation levels reflected infant temperament, which was reported to us by the parents. The children with higher methylation levels at 18-months, and presumably lower levels of oxytocin receptor, were also more temperamental and less well balanced," Krol said.
According to the researchers, early social interaction with caregivers -- including fathers -- can influence our biological and psychological development through chemical changes to the genes behind the oxytocin system.