A different line of evidence about oxytocin’s role in love comes from genetics. “With hormones you can say that maybe behavior created the hormone or the hormone created the behavior—we don’t know,” Feldman says. But a person’s genes are in place before any behavior can emerge, she notes.
A study published last year in Biological Psychiatry was the first to assess whether people with variations in their oxytocin-receptor gene have a harder time maintaining romantic relationships than those who don’t. Hasse Walum, a graduate student at Karolinska Institute in Stockholm, and his colleagues took advantage of Swedish twin studies that included thousands of participants, their genetic information and their answers to questions about how affectionate they were with their romantic partners. They found that women with a specific variation weren’t as close to their partners as women without it: they kissed their partners less and didn’t desire physical proximity as often. These women were also more likely to report having had a marital crisis. Although researchers don’t know exactly how this variation affects the oxytocin system, it may result in a lower number of oxytocin receptors in the brain. People with fewer receptors would be less sensitive to the hormone’s effects.
In a study that hasn’t been published yet, Feldman found that oxytocin receptor genes are also linked to empathy in couples. She looked at variants in the gene that have been linked with an increased risk for autism, a disorder that is marked by major social communication deficits. She found that the more of these “risk variants” a person had, the less empathy they showed toward their partner when that partner shared a distressing experience.
Oxytocin has been shown to help people with autism improve their ability to recognize emotion, and Wallum found that the same receptor variant that increases risk for marital crisis in women is linked to social problems in girls. These include trouble getting along with others and a preference for being alone. This and Feldman’s work on oxytocin’s importance for the mother–child bond suggests that the hormone is more involved in the communication component of love between couples than the romantic component of love.
Adam Guastella, a clinical psychologist at University of Sydney’s Brain and Mind Research Institute, and a pioneer in studies of how oxytocin can help people with autism, thinks the hormone can also help people in couple therapy by facilitating empathic communication. His research has shown that people who get oxytocin are more focused on positive emotion: they remember happy faces better than angry and neutral ones. Research by others has shown that oxytocin increases trust, generosity and our ability to identify emotion in facial expressions. It is perhaps by these mechanisms that the hormone improves communication.
Guastella and his team just completed an unpublished study that is the first to test the effects of oxytocin on couples in therapy. In one part of the study, couples were asked to discuss a “hot topic,” one that usually led to conflict between the pair, and to then try to solve the issue. Although the data analysis is still in progress, Guastella expects couples that got oxytocin to show less hostile interpretations of the problem and be less critical of their partners. He thinks overall it will increase perspective-taking and reduce blame, leading to smoother communication and better problem-solving.
How would that work? Feldman thinks that these types of behaviors are intimately linked with oxytocin in a positive feedback loop. “Oxytocin can elicit loving behaviors, but giving and receiving these behaviors also promotes the release of oxytocin and leads to more of these behaviors,” she says. She thinks that talk therapy alone can boost the oxytocin system, but admits that in some cases it might help to jump-start the feedback loop by administering oxytocin. If Guastella’s results support his hypothesis, talk and hormone therapy together might be the best recipe for breaking down dysfunctional communication between partners, especially in cases where the behaviors have been learned in childhood.