Born to Cuddle - Hormone Oxytocin

The cuddle chemical has a dark side. Oxytocin – a hormone thought to play a role in maternal bonding, trust and even attraction – amplifies feelings of envy and gloating, research suggests.

Volunteers who played a game involving monetary gains and losses felt more envy after an imaginary opponent's wins if they had received a dose of oxytocin, compared with a placebo.

Similarly, oxytocin boosted feelings of schadenfreude – pleasure at another's misfortune – after volunteers won more money than their opponent.

"The bottom line is that [oxytocin] doesn't only work on pro-social, positive emotions, it has a general effect on social emotions and it depends on the context," says Simone Shamay-Tsoory, a cognitive scientist at the University of Haifa, Israel, who led the study.

Attraction to aggression

Previous work on animals has hinted at oxytocin's double life. Female hamsters that received an infusion of oxytocin into a brain area where the hormone is known to have an effect responded more aggressively to intruders than hamsters that got no oxytocin.

Newborn female voles that received an injection of oxytocin later responded more aggressively to males than other females.

Studies with humans, on the other hand, have suggested that oxytocin makes us more likely to trust others, find them attractive, and remember their faces. We even receive a flood of the stuff when we play with our pooches. "No one actually examined if it can be involved in negative social emotions," says Shamay-Tsoory.

However, she admits her team expected to find that feelings of envy and gloating were tempered by the hormone.