Want to make those inevitable fights with your partner less troublesome? A spritz of the “love hormone” oxytocin could help, by encouraging cooperation in men and making women behave more approachably, a new study suggests.
The hormone may also help people read social cues more accurately, according to a second study in the same journal, Social Cognitive and Affective Neuroscience. That suggests oxytocin may not only ease social interaction, but that the hormone could also someday help people with socially impairing conditions like autism interact with others.
Oxytocin is a complicated character. It’s commonly called the “cuddle chemical” — the brain chemical is involved in orgasm, social bonding, pregnancy and breast-feeding — but in other circumstances, it has the opposite effect, increasing aggression against outsiders or spurring distrust and rejection rather than affection in some people who have had difficult childhoods.
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The two new studies illuminate the nuanced effects of the hormone: in the first study, researchers found that oxytocin had opposing, but complementary effects on men and women in romantic relationships, who were given a dose of the drug before discussing a contentious point in their relationship. When both people got oxytocin, their conflict resolution improved.
The research involved 47 healthy heterosexual couples who were either married or had been living together for at least a year; they were happy in their relationships and not seeking therapy. Before being given either oxytocin or placebo, they were told to pick two areas of disagreement in their relationship; after the oxytocin took effect, the couples discussed those issues with each other while being videotaped.
Men who received oxytocin rather than placebo responded more positively to their partners during their dispute, paying more attention to them and responding more cooperatively. Physically, their levels of emotional arousal increased, which researchers gauged by tracking levels in the saliva of a chemical linked with autonomic nervous system activity. The autonomic nervous system is responsible for generating emotional and physical states, such as fear, anger, happiness and the fight-or-flight response — and the men’s behavioral changes occurred in tandem with changes in their autonomic activity.
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In women, oxytocin had the opposite effect: it reduced their autonomic response, making the women more friendly and approachable. The different results by gender may be linked to the fact that the autonomic nervous system has two primary functions that counteract each other: the sympathetic nervous system boosts arousal and triggers the fight-or-flight response, while the parasympathetic nervous system promotes a calming response, returning to the body to a neutral state. Perhaps boosting one function while suppressing the other could produce complementary effects depending on gender.
The authors suggest that the variation corresponds to the different ways men and women tend to respond to stress. Men are more likely to go into fight-or-flight mode, which raises arousal and makes them prone to approach, while women typically engage in a tend-or-befriend” strategy with calmer physiology, which makes them more approachable. In its role in facilitating bonding between couples, therefore, oxytocin may tune the stress system to generate the best response from each gender in order to reduce conflict. The authors write that oxytocin “may have driven quiescence in women and…‘approach’ behavior in men.”
The second study, published in the same journal, reveals a possible mechanism for how oxytocin actually works its magic on social behavior, by examining the hormone’s effect on people’s ability to read emotional expressions in faces.
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Forty healthy volunteers had their pupil dilation monitored as they tried to detect either hidden or explicit emotional expressions in images of faces. Pupil dilation is often used in research to indicate a person’s interest, attention or “cognitive load.” The authors note that “oxytocin significantly enhanced the pupil dilation response for all facial expressions presented.”
What does that mean in terms of the ability to interpret facial expressions appropriately? “[O]xytocin consistently enhances the perception of others’ facial expressions, ‘sharpening’ the impression such that happy faces appear more happy and less angry, whereas angry expressions appear more angry and less happy,” the authors write. “This type of evaluative ‘sharpening’ could represent one mechanism by which oxytocin enhances sensitivity to simple as well as more complex emotional expressions.”
In other words, the hormone may act on the brain by literally focusing visual attention on important social information and making it seem more distinct. But the effect was most pronounced in people who started out with difficulty reading social cues. People who were already sensitive to detecting emotion showed little change after receiving the oxytocin.
All of this suggests that oxytocin could be particularly useful for people with autism, a condition that is marked early in life by reduced interest in most social signals and experiences. “We think that oxytocin plays a critical role in social attachment and social cognition,” says Dr. Eric Hollander, a clinical professor of psychiatry at Montefiore/Albert Einstein School of Medicine, who studies the use of oxytocin in people with autism and was not associated with the current research. “One of the problems in autism is that social information is not being tagged as salient, so enhancing oxytocin should help in terms of salience, so that they can start to pay more attention to social information,” he says.
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Indeed, a case report published this week in BMC Psychiatry showed that a 16-year-old autistic girl who was given oxytocin daily for months experienced dramatic improvement. Prior to starting oxytocin, the Japanese teen had had few friends and frequent emotional outbursts. She had difficulty understanding others and obsessively played videogames alone. The authors write:
One month after starting nasal oxytocin spray administration, the girl’s social behaviors began to improve. The duration in which she closeted herself in her room became short. She greeted other people and made small talk with them, and she also showed empathy for others’ sickness and worries. She became able to express gratitude to her family for their support.
She became able to carefully listen to her family’s conversation, and showed attenuated expressions of rebellion to the family’s words of caution. Even when she lost her temper, she calmed down immediately. A teacher who taught her about culture and who did not know about her treatment noted decreases in the numbers of episodes of irritability and self-injury, and was surprised at the increases in the frequencies of daily conversations and happy facial expressions in the presence of other people.
If controlled trials and additional lines of research bear out, oxytocin may someday play an important role in the treatment of autism. It could also potentially help with other disorders like schizophrenia, which are marked by social withdrawal. In addition, researchers are studying oxytocin for the treatment of addiction, in which social difficulties often precede the development of substance misuse.
But given that research has shown that oxytocin can also have some negative emotional effects — notably in people with borderline personality disorder — it’s not yet ready for home use in autism or in couples’ counseling outside of experimental settings.
Maia Szalavitz is a health writer at TIME.com. Find her on Twitter at @maiasz. You can also continue the discussion on TIME Healthland’s Facebook page and on Twitter at @TIMEHealthland.