Per economist Paul Zak, the human brain generates oxytocin in response to experiences in which we feel close to others - weddings, hugs, receiving a gift - and this oxytocin helps us to feel greater empathy in return, and to act more generously toward others in general. He calls oxytocin "the moral molecule", because oxytocin-induced empathy will cause people to act more positively toward others around them.
You can watch his TED presentation on the topic here; his eight-hugs-per-day prescription comes at the end:
This research leads to obvious questions about moral liability for people whose oxytocin-generating mechanisms are defective, and about the ethical use of oxytocin, or oxytocin-generating actions, in order to influence the behavior of others.
It also leads me to think about the methods of successful politicians and fundraisers - the ones who hug, maintain contact, ask how you are doing, try to help you, and so on. Capitalizing on an empathy-building bond is nothing new, but providing a chemical basis for it is interesting.
The big question in my mind, though: What is it about these empathy-triggering interactions that makes our brain perceive them as worthy of oxytocin? What teaches the brain to view these as bonding experiences?