What if helping others is an innate part of being human? What if it just makes us feel good to give? Those questions have inspired a series of ground-breaking neuroscience studies ... by researchers Jamil Zaki, an assistant professor of psychology at Stanford University, and Jason Mitchell, an associate professor of the social sciences at Harvard University. Zaki and Mitchell's research has gone head-to-head with standard economic models of decision making, which assume that when people exhibit kind, helpful (or pro-social") behavior, they are doing so to protect their reputation, avoid retribution, or benefit when their kindness is reciprocated. But in a study published in 2011 in the prestigious Proceedings of the National Academy of Sciences, Zaki and Mitchell tested an alternate theory: that we feel good when helping others ... because behaviors like fairness, cooperation, and reciprocity are intrinsically rewarding. They found that acting equitably ... is rewarding, even when it means putting someone else's interests before our own. On the other hand, making inequitable choices activated ... a brain area that has been associated with negative emotional states like pain and disgust. "Our model flips the traditional model on its head," says Zaki. "Instead of people wanting to be selfish and then forcing themselves through control to be generous, we're getting a picture where people enjoy being generous."