Dacher Keltner, Ph.D., is the founding director of the Greater Good Science Center and a professor of psychology at the University of California, Berkeley. He is the author of The Power Paradox: How We Gain and Lose Influence and Born to Be Good, and a co-editor of The Compassionate Instinct. This article originally appeared in Greater Good, the online magazine of the Greater Good Science Center at the University of California, Berkeley. For more, see greatergood.berkeley.edu.