Scientists believe that the hormone oxytocin is responsible for creating intimate bonds between humans... But there's much more to it than just being Love Potion No. 9, as new studies are showing: Finches beware!
The Guardian reports that researchers at Indiana University have experimented with finches' levels of mesotocin, the finch version of oxytocin:
When the scientists... gave drugs that block mesotocin receptors to zebra finches – which are normally highly social creatures – the birds spent much less time with familiar individuals and more time with unfamiliar individuals. They also preferred to hang out in smaller groups. By contrast, zebra finches given extra mesotocin became more social and spent more time with familiar faces... Intriguingly, the same paper suggests that the distribution of oxytocin receptors in the brain might help to explain why some animals are more social than others. When the researchers compared three flocking finch species with two territorial, aggressive species, they found that the more social species had more mesotocin receptors in a part of the brain called the lateral septum. Blocking these receptors made the birds become less social.
This fits with existing theories about oxytocin's necessity in human interactions, but apparently it's not as simple as that:
[A]nother recent study serves as a warning not to get too carried away. Researchers at the University of Haifa in Israel found that volunteers who inhaled oxytocin before playing a competitive game felt more envy when they lost and more schadenfreude when they won.
So there you have it: Oxytocin - The chemical that will make you act like an idiot, whether or not you like someone.
Party people: Gregarious types may have more oxytocin receptors [Guardian Science Blog]