Oxytocin: Not just for women

Everybody eventually catches the love bug or the cuddle monster. As great as that strong feeling of love and attraction is, it can largely be attributed to just one molecule: oxytocin. Oxytocin is a hormone and neurotransmitter that is active in reproductive and attraction-based signaling systems. It’s probably best-known for its function in childbirth, during which oxytocin induces delivery and later lactation; however, the hormone also plays a crucial role in both genders in pathways such as sexual activity, social bonding, and stress. New research has shown that this typically maternal molecule is active in helping fathers bond with their children as well.

Previous research has shown that oxytocin affects the behavior of men who are in a relationship. In addition to being a key hormone in sexual activity, oxytocin also seems to play an important role in bonding between romantic partners. In one study, a group of men in monogamous heterosexual relationships were dosed with oxytocin and then shown either photos of their partner or photos of random women. Under MRI imaging, the brain showed significantly higher activity when the men looked at photos of their own partners rather than at photos of other women. Later on, in a similar study, men were dosed with either oxytocin or placebo and were then led into a room where they interacted with an attractive female researcher. Unsurprisingly, the men who were both treated with oxytocin and already in monogamous relationships felt more comfortable when the attractive researcher stood at a greater distance away from them. These experiments, among many others, suggest that oxytocin plays a critical role in monogamy for men.

A father is holding his son and smiling. Oxytocin facilitates these kind of father-son relations, not just for the mothers. Image courtesy of Pixabay.

Oxytocin’s effects on male monogamy might occur because the molecule heightens a person’s ability to empathize and feel emotions. Some studies even suggest that high levels of oxytocin actually make people overly empathetic, recognizing a greater intensity of emotions in others. There is also evidence that the increased emotional sensitivity caused by oxytocin can help couples communicate. In one study, couples were dosed with oxytocin or a placebo and then led into a disagreement. Couples who had been dosed with oxytocin were able to communicate more effectively and to better de-escalate the situation than couples who had received placebo. In healthy couples, physical contact such as kissing, touching, and cuddling can actually stimulate the release of oxytocin in both partners, creating a positive feedback loop that improves trust and emotional sensitivity between partners.

Considering these studies, it’s not revolutionary that there is also a link between oxytocin and the way fathers bond with their toddlers, as shown in a recent study. “There is now evidence that oxytocin can increase in men who become fathers. Other labs have also shown that giving men additional, exogenous oxytocin intranasally stimulates positive paternal behaviors,” said James Rilling, professor at Emory University and one of the authors of this study. Building on this previous research, Rilling and his team at the Laboratory for Darwinian Neuroscience have demonstrated that oxytocin levels may be a factor in how involved fathers are in caregiving. Fathers of toddlers between the ages of one and two were dosed with either oxytocin or a placebo and then shown pictures of their toddler, a random toddler, and a random adult. Using MRI imaging, the researchers measured brain activity in response to each photograph. Like in other studies, the fathers dosed with oxytocin showed a much greater neural response to their own child than to the other photographs of random individuals, suggesting that oxytocin plays a critical part in these close, familial social interactions.

“Oxytocin acts on targets of the brain’s dopamine reward system to render child stimuli more rewarding, which may increase the motivation to interact with the child,” Rilling said. As with a romantic partner, spending time with their children can stimulate the release of oxytocin in fathers, which then contributes to the brain’s reward system, encouraging similar behavior. Thus, what was previously considered a maternal hormone serves a similar purpose when men interact with their kids. At the end of the day, however, what really matters isn’t a parent’s hormonal make-up, but that every child receives the love and care they deserve.