"The only reason this works is because we've asked you to take the other person's perspective. So we had this control task in which we didn't ask you to take the other person's perspective, and oxytocin had no effect," Zak says. "We do have some baseline altruism, so we found that a bit of the generosity was predicted by altruism, but empathy was quantitatively twice as important as baseline altruism.
"So it's really empathy and not altruism that seems to drive charitable giving," he says. "Now we understand why people actually give money to the Salvation Army when they leave their local store at Christmastime, why they give money to hurricane victims. We do that because we feel for them, we feel empathy for them.
In his controlled experiments, Zak deliberately removed any natural stimulators of oxytocin and empathy, and used artificial oxytocin to "push on the empathy lever" of some participants.
But he points out that there are many natural ways to boost our oxytocin levels-- including giving itself.
"We're being generous with others and we're releasing oxytocin in ourselves and in other people and we get great enjoyment from that," he says. He adds that it's well-known that hugging and cuddling also release the hormone but says so does sharing a meal with others.
"The rituals of the holidays, which often include many meals, is an important part of the bonding that we have between those friends and family that join us," he says.
Interestingly, Zak found that oxytocin had no effect on two percent of the participants and that these students fit the personality profile of sociopaths.
"If we infuse oxytocin into their brains, it has no effect on their behavior, so they're not generous at all," Zak says, claiming, "That's a good thing. It tells us there are individuals out there who are not people we want to interact with and we should be careful when we're having to trust another person and we should direct our generosity towards those who really need it."
This research was published online in PLoS One, November 2007, and funded by The Seaver Institute and the John Templeton Foundation.