Having good friends benefits our health, happiness and overall life satisfaction. Despite friendship’s importance, we had little understanding of how we learn to make friends. New evidence from Ruth Feldman at Bar-Ilan University in Israel showed for the first time that early parenting and biology interact to shape how we relate to our friends.

Feldman’s work showed that how a 3-year-old child interacts with their best friend is determined in part by how their oxytocin system functions and in part by how their parents, particularly their mother, interacted with them. When playing with their best friend, children with higher levels of oxytocin and whose parents engaged in more parenting behaviors were more communicative and collaborative, two traits that help increase closeness and cement bonds.

Oxytocin is a hormone that acts primarily in the brain and influences social behavior. For example, artificially increasing a person’s oxytocin levels by squirting the hormone into his nose can lead him to be more generous in a game where he gets to divide $10 between himself and a partner. But oxytocin levels can only explain so much of our behavior. A dozen squirts of oxytocin won’t cause a miser to give his paycheck to the Red Cross. Our behavior also comes from our upbringing.

To better understand the contributions of oxytocin and parenting, Feldman followed 50 couples and their firstborn child during the first 3 years of life. At one- and six-months after birth, she asked the father to “play with your infant as you typically do” for 10 minutes. Then the mother had her turn.

Each parent was scored based on how much of that time they spent nurturing their child, such as gazing at, speaking to, touching their child or expressing positive emotions. Both parents provided blood samples to have their oxytocin levels measured. For both mothers and fathers, having higher oxytocin levels was linked to more time nurturing their child.

At 3 years, both parents again played with their child. The mother and father provided blood and the child provided saliva samples to measure oxytocin levels. This time, behavior during play was judged on reciprocity. Did parent and child move in the same direction and adapt to each other’s needs? Did they engage in give-and-take interactions and mutual dialog?

Mothers that spent more time involved in parenting behavior in the first year had more reciprocity with their child at 3 years. Fathering in the first months after birth, however, was not related to father-child reciprocity at 3 years.

Then, each child got to play with her best friend for ten minutes. Who says research can’t be fun? This provided a chance to test attachment theory, the idea proposed by developmental psychologist John Bowlby that children learn to interact with friends after forming strong attachments with their parents.

Mothering and fathering during the first months of life were not related to the child’s friendship behavior at 3 years. However, in line with attachment theory, mothering during the first months was related to mother-child reciprocity at 3 years, and children who showed more reciprocity with their mother also showed more reciprocity with their best friend. This suggests that good parenting does not stop in infancy, but is a continual process that influences the child through the early years of development.

The child’s physiology also influenced how they behaved. Children with higher levels of oxytocin showed greater social reciprocity with their best friend.  

One of the most novel findings was a gene-by-environment interaction with the gene CD38, which promotes oxytocin release in the brain. Children whose mothers had a version of the CD38 gene that promotes low oxytocin levels but received more care in the first 6 months had the same oxytocin levels as children whose mothers had a version that promotes higher oxytocin levels. Good parenting seems to serve as a protective factor if the mother possesses low-oxytocin-producing genes, and their children show no difference in oxytocin.

In testing attachment theory’s prediction that a child’s relationship with her parent serves a springboard to her relationship with peers, Feldman found evidence to support it, but also to suggest that it is incomplete. When children form bonds with friends, they rely not just on modeling their parents’ behavior, but according to Feldman, “also on the functioning of their own oxytocin system.”  

Nature and nurture both contributed to how the child interacted with her friend and her oxytocin levels. How we make friends is determined not just by our genetic blueprint, but also by the team that oversees its fulfillment.

Image credit: thejbird

Reference: Feldman R, Gordon I, Influs M, Gutbir T, Ebstein RP. Parental Oxytocin and Early Caregiving Jointly Shape Children's Oxytocin Response and Social Reciprocity. Neuropsychopharmacology. 2013 Jun;38(7):1154-62. doi: 10.1038/npp.2013.22.

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