Oxytocin is usually described as the ‘trust hormone’ owing to its involvement in social bonding but a new study covered by Scientific American suggests it may have a wider role in human interaction as it has been found it increase feelings of envy and gloating.

The study, led by psychologist Simone Shamay-Tsoory, used a familiar format in oxytocin research. It asked participants to play a competitive game while half were given a nasal spray containing the hormone and half were given a placebo spray.

Although they thought they were playing another participant, in reality, they were playing a computer programmed to act in a certain way to elicit competitive emotions:

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 also measured mood in general and found no change, suggesting the increase in negative feelings toward others couldn’t be explained as a general intensifying of emotions.

In their paper, they note several exceptions to the media stereotype that oxytocin is a ‘hug hormone’, citing studies that it increases aggression and territorial defence in some species. Also contrary to the cliché, a recent study [pdf] found it had no effect on empathy for other people’s pain.

They conclude that, rather than being a something that promotes trust and bonding, oxytocin enhances all social emotions, including the good, the bad and the ugly.

Link to SciAm on oxytocin and envy study.

Link to abstract of study.