The hormone oxytocin may be the "cuddle chemical" but recent research has found that oxytocin can promote negative emotions too.

Salespeople love oxytocin - they think if they spray it on customers will trust them more.  Mothers bond with babies due to oxytocin.  It's positive effects are well known but studies have also found that oxytocin can increase gloating and envy.

Andrew Kemp of the University of Sydney co-wrote a paper in Current Directions in Psychological Science with colleague Adam Guastella why darker social emotions may come with oxytocin. Studies finding negative emotions "kind of rocked the research world a little bit," Kemp says, and it has led some researchers to think that oxytocin promotes social emotions in general, both negative and positive.

Kemp and Guastella think oxytocin's role is slightly different. Rather than supporting all social emotions, they think 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," Kemp says. "It's an approach-related emotion: I want what you have." Gloating is also about approach, he says; people who are gloating are happy—a positive, approach-related emotion—about having more than their opponent and about that person's misfortune.

If Kemp and Guastella are right, that could mean that oxytocin could also increase anger and other negative approach-related emotions. That could have important implications for people who are studying how to use oxytocin as a psychiatric treatment. "If you were to take a convicted criminal with a tendency towards aggression and give him oxytocin to make him more social, and if that were to enhance anger as opposed to suppressing anger, then that has very substantial implications," Kemp says.

Further research will show more about what emotions are promoted by oxytocin, Kemp says. "This research is really important because we don't want to go ahead and attempt to treat a range and variety of psychiatric disorders with oxytocin without fully understanding the impact this may have on emotion and mood."