Recent research has revealed that Oxytocin - the "cuddle chemical" hitherto known to promote positive feelings, and the hormone that helps mothers bond with their babies, can promote negative emotions, too.
"Quite a number of studies have shown it's actually not that simple," said Andrew Kemp of the University of Sydney, who co-wrote the paper with his colleague Adam Guastella.
Recent studies have found that people who were given oxytocin, then played a game of chance with a fake opponent, had more envy and gloating. These are also both social emotions, but they're negative.
"It kind of rocked the research world a little bit," added Kemp.
That led some researchers to think that oxytocin promotes social emotions in general, both negative and positive.
But Kemp and Guastella think oxytocin's role is slightly different. Rather than supporting all social emotions, they thought it plays a role in promoting what psychologists call approach-related emotions. These are emotions that have to do with wanting something, as opposed to shrinking away.
"If you look at the Oxford English Dictionary for envy, it says that the definition of envy is to wish oneself on a level with another, in happiness or with the possession of something desirable," said Kemp.
"It's an approach-related emotion: I want what you have," added Kemp.
Gloating is also about approach, he said; people who are gloating are happy-a positive, approach-related emotion-about having more than their opponent and about that person's misfortune.
The study has been published in the Current Directions in Psychological Science, a journal of the Association for Psychological Science.