Breathing in the hormone oxytocin has been shown in recent years to trigger all kinds of feel-good emotions in people, such as trust, empathy and generosity. Now scientists find it might have a dark side: Snorting oxytocin might also incite envy and gloating.



Past studies have shown that oxytocin plays a wide role in social bonding in mammals—between mates, for instance, or mother and child—and recent work suggested the hormone was linked with pro-social behavior in people, such as altruism.



Still, neuroscientist Simone Shamay-Tsoory in University of Haifa in Israel and her colleagues noted that oxytocin was found to raise aggression in rodents, suggesting the hormone might play a wider role in social emotions in humans. The researchers decided to investigate envy and gloating—feelings related to the tendency to compare oneself with others—to see if oxytocin ramped up these emotions or dialed them down.



The researchers gave 56 volunteers either oxytocin or a placebo and paid them to take part in a game of chance with another participant which, unknown to them, was a computer. They were shown three doors on a video screen, either red, blue or yellow, and told that behind each door was a different sum of money they could keep after the game.



The computer was programmed to either win more money than the players to trigger feelings of envy, lose more money to elicit a form of gloating known as schadenfreude (delight over another's misfortune) or to win or lose equal amounts of money. To encourage these negative emotions, the researchers gave the computer player an arrogant "personality". They did this by asking the volunteers to appraise their chances of winning more money than the other player; although nearly all volunteers predicted 50–50 odds, they were told their opponents gave themselves an 80 percent chance of winning.



When compared with a placebo, volunteers who inhaled oxytocin said they felt greater levels of envy or gloating when they lost or won more money than the computer, respectively—findings the researchers detailed online July 29 in Biological Psychiatry. On the other hand, when the volunteers were questioned after the game, inhaling oxytocin apparently had no effect either following gains of equal amounts of money or on mood in general.



The researchers suggest oxytocin might promote the intensity of social emotions in general, leading to more generosity and trust in positive contexts and more envy and gloating in competitive situations. Shamay-Tsoory notes that scientists are investigating oxytocin for a number of psychiatric treatments to enhance positive feelings in autism, social phobias and other disorders. "We suggest that it is essential to also inventory potential undesirable effects of such treatments," she says.



Psychologist Beate Ditzen at the University of Zurich, who did not participate in this study, notes this work does show that oxytocin does not have solely positive effects in humans. She conjectures, however, that negative effects might still have pro-social effects in the long term—other studies hint that the threat of punishment may be key to cooperation.



To better understand these seemingly contradictory effects of oxytocin, cognitive neuroscientist Mauricio Delgado at Rutgers University suggests it would be interesting to see how the hormone's effects on an emotional response such as envy might influence actual behavior, such as whether to trust money with a potential investor.



"Based on the current paper, you would expect a person with greater feelings of envy to also not 'trust' or share money with another individual, therefore supporting the notion that oxytocin is not involved with pro-social behaviors exclusively," Delgado explains. "However, it is possible that oxytocin makes a person feel envious, but at the time of acting or making a decision they still display pro-social attitudes—sharing with the other individual—thus reconciling the discordant findings."