Oxytocin affects social bonds - can we influence oxytocin in children?

© 2019 Gwen Dewar, Ph.D., all rights reserved

Oxytocin is often called the “hormone of attachment” because it seems to help individuals bond with other members of their in-group.

A surge of oxytocin makes us feel more trusting and generous toward our social partners (e.g., Baumgartner et al 2008; Zak et al 2007). It encourages us to tend and befriend. It can help us relax together. Oxytocin counteracts the effects of stress, reducing blood pressure, anxiety, and fear (Patin et al 2018; Uvnäs Moberg and Prime 2013).

If you’ve given birth or breastfed, you’re no stranger to oxytocin. The hormone is necessary for childbirth, and it helps orchestrate lactation. But oxytocin is related to parenting in other ways, too.

In experiments on nonhuman animals, oxytocin motivates mothers to approach and nurture their offspring (Numan 2007). Does the same thing happen in humans?

So far, there is non-experimental evidence for a similar effect in women: Mothers who show high baseline levels of oxytocin tend to treat their babies with greater sensitivity and responsiveness (Scatliffe et al 2019).

There is also experimental evidence for an intriguing effect in men. A recent study found that administering extra oxytocin to fathers made them feel more rewarded by positive contact with their children. In addition, the boost in oxytocin seemed to activate brain regions associated with empathy (Li et al 2017). So maybe oxytocin makes fathers feel more attuned to their children.

This is all very cool stuff, especially since we can trigger the release of oxytocin through natural means.

Mothers experience surges when they are breastfeeding, and also after engaging in lots of affectionate contact with their babies (Scatliffe et al 2019).

Fathers experience elevated oxytocin levels after a bout of stimulating, happy play with their babies (Feldman et al 2010).

And let’s be clear. You don’t need babies to trigger a release of oxytocin in your brain.

Adults have been shown to respond positively to many different kinds of pleasant social interactions, including interactions with other adults.

Studies show that we can trigger oxytocin spikes through affectionate touch and friendly conversation. In some experiments, researchers were able to increase people’s oxytocin levels by simply asking folks to think about their loved ones.

But what about our kids? Can we do things to boost oxytocin in babies and children?

Babies begin producing their own oxytocin even before they are born, and it looks as though they respond a lot like adults. For instance, skin-to-skin contact appears to raise oxytocin levels in both parents and infants (Vittner et al 2018).

And an experiment on school-aged children confirms that big kids can get an oxytocin boost when their parents offer emotional support. Affectionate physical contact does it. So does affectionate conversation (Selzer et al 2010).

So we have good reason to believe that sensitive, responsive parenting can cause immediate spikes of oxytocin in babies and children.

But there’s even more. New research suggests that parents can shape the way a baby’s oxytocin production system develops.

By offering babies lots of sensitive, responsive care, we may help keep crucial genes – oxytocin receptor genes – open for business. And this helps ensure that our children will keep enjoying the effects of oxytocin as they get older.

The evidence comes from two studies – an experiment on nonhuman animals (prairie voles), and an epigenetic study tracking the development of human infants.

The details get a bit technical, but the basic ideas aren’t hard to grasp.

A tale of two studies

Both studies focus on a phenomenon called methylation, a process that blocks the normal functioning of portions of our DNA.

In this case, the DNA we care about is a gene for making oxytocin receptors – little proteins that allow our brains and bodies to use oxytocin.

Some cells in the brain are little factories for making oxytocin receptors. But if the DNA in a cell becomes methylated – if the genetic code for making the oxytocin receptors gets blocked – the production line grinds to a halt. That cell stops producing oxytocin receptors.

This can happen in a few cells, here and there, without having any notable impact on the brain’s use of oxytocin. But if methylation becomes widespread, you will probably notice effects. You’ll be less likely to experience the “tend and befriend” effects of oxytocin. And you’ll have one less tool in life to help you de-stress.

That’s the theory, and there’s evidence suggesting that methylation of the oxytocin receptor gene really does affect our behavior. People who test with higher levels of methylation are more likely to have problems with social, cognitive, and emotional functioning (Maud et al 2018).

So why does methylation happen? Decades of research suggests that methylation – and reversals of methylation – can be triggered by environmental factors. And guess what?

In the case of the oxytocin receptor gene, it appears that parenting is a major factor.

Take the study of prairie voles – cute, hamster-like rodents known for their intense social bonds.

In experiments, researchers varied the amount of parental care that babies received from their parents. Then they looked for long-term trends in the methylation of the oxytocin receptor genes. How did babies turn out?

When prairie vole babies received low levels of early care – relatively little snuggling, grooming, and licking from their mothers – they experienced more methylation.

When prairie vole babies received lots of this affectionate care, they experienced less methylation (Perkeybile et al 2018). Good news for developing an active, responsive system of oxytocin production.

What about humans?

Nobody’s going to randomly assign babies to receive different levels of parental care. So experiments are out. But researchers have tried another approach:

Watch mothers and young babies interact.
Note individual differences in the ways that mothers behave toward their infants.
See if these differences end up predicting differences in the amount of methylation that babies develop over time.

Kathleen Krol and her colleagues conducted this kind of study on 101 mother-infant pairs.

When the babies were 5 months old, the researchers watched mothers and infants play together for several minutes. The researchers noted how talkative and engaged mothers were as they played a game.

The researchers also measured oxytocin receptor gene methylation in both mothers and babies. Then, a year later, the researchers measured methylation again. Were there any changes?

The mothers didn’t change much at all. Their levels of methylation were pretty steady throughout the study.

But for babies, the story was different. They were much more likely than their mothers to have experienced changes in methylation.

Some babies experienced increases in methylation over time. Other babies experienced decreases.

And when researchers looked back at the parenting data, they found that those 5-month-old play sessions were predictive. If a mother had shown a lot of involvement during the game, her baby tended to experience greater reductions in methylation one year later.

Interestingly, the researchers also found a connection between methylation and infant temperament at 18 months. Babies with higher levels of oxtytocin receptor methylation showed greater irritability in response to sensory stimulation. They were more likely to react negatively to bright lights, grating sounds, scratchy fabrics, and other intense, sensory stimulants (Krol et al 2019).

Can we be sure it was differences in mothers’ behavior that caused some babies to experience reduced methylation? No. That isn’t something you can prove in a study like this. It wasn’t a randomized, controlled experiment.

But Krol’s team checked for at least one alternative explanation.

You might wonder if the babies’ own behavior might have led to increased methylation. Irritable babies may experience more stress, and stress, too, might affect methylation. So maybe a highly irritable 5-month-old baby is more likely to experience methylation over time, irrespective of how his or her mother behaves.

But that isn’t what happened here. The researchers found that infant behavior at 5 months had no significant effect on levels of methylation one year later.

So what’s the takeaway?

Given the results of this study — and the experimental work on voles — I think we have good reason to think that parents can influence the development of a baby’s oxytocin response system.

There’s also solid evidence in support of the idea that we can induce immediate, short-term surges of oxytocin in our children.

It’s another reminder that sensitive, responsive parenting can have a profound impact on our kids — on their emotional, cognitive, and physical well-being. So snuggle up, and look after your own mental health needs. Parenting can be stressful, and when you’re stressed out, it’s harder to experience — and pass along — the benefits of oxytocin.

References: Oxytocin in parents and children

Baumgartner T, Heinrichs M, Vonlanthen A, Fischbacher U, Fehr E. 2008. Oxytocin shapes the neural circuitry of trust and trust adaptation in humans. Neuron. 58:639–650.

Cascio CJ, Moore D, McGlone F. 2019. Social touch and human development. Dev Cogn Neurosci. 35:5-11.

Feldman R, Gordon I, Schneiderman I, Weisman O, Zagoory-Sharon O. 2010. Natural variations in maternal and paternal care are associated with systematic changes in oxytocin following parent-infant contact. Psychoneuroendocrinology. 35(8):1133-41.

Glasper ER, Kenkel WM, Bick J, Rilling JK. 2019. More than just mothers: The neurobiological and neuroendocrine underpinnings of allomaternal caregiving. Front Neuroendocrinol. 53:100741.

Krol KM, Moulder RG, Lillard TS, Grossmann T, Connelly JJ. 2019. Epigenetic dynamics in infancy and the impact of maternal engagement. Sci Adv. 5(10):eaay0680.

Li T, Chen X, Mascaro J, Haroon E, Rilling JK. 2017. Intranasal oxytocin, but not vasopressin, augments neural responses to toddlers in human fathers. Horm Behav. 93:193-202.

Maud C, Ryan J, McIntosh JE, Olsson CA. 2018. The role of oxytocin receptor gene (OXTR) DNA methylation (DNAm) in human social and emotional functioning: a systematic narrative review. BMC Psychiatry. 18(1):154.

Numan M. 2007. Motivational systems and the neural circuitry of maternal behavior in the rat. Dev Psychobiol. 49(1):12-21.

Patin A, Scheele D, Hurlemann R. 2018. Oxytocin and Interpersonal Relationships. Curr Top Behav Neurosci. 35:389-420.

Perkeybile AM, Carter CS, Wroblewski KL, Puglia MH, Kenkel WM, Lillard TS, Karaoli T, Gregory SG, Mohammadi N, Epstein L, Bales KL, Connelly JJ. 2018. Early nurture epigenetically tunes the oxytocin receptor. Psychoneuroendocrinology. 99:128-136.

Scatliffe N, Casavant S, Vittner D, Cong X. 2019. Oxytocin and early parent-infant interactions: A systematic review. Int J Nurs Sci. 6(4):445-453

Selzter LJ, Ziegler TE, and Pollack SD. 2010. Social vocalizations can release oxytocin in humans. Proc Biol Sci. 277(1694):2661-6.

Uvnäs Moberg K and Prime DK. 2013. Oxytocin effects in mothers and infants during breastfeeding. Infant 9(6): 201-06

Vittner D, McGrath J, Robinson J, Lawhon G, Cusson R, Eisenfeld L, Walsh S, Young E, Cong X. 2018. Increase in Oxytocin From Skin-to-Skin Contact Enhances Development of Parent-Infant Relationship. Biol Res Nurs. 20(1):54-62

Zak PJ, Stanton AA, Ahmadi S. Oxytocin increases generosity in humans. PLoS One. 2007;2:e1128.