NSF's Directorate for Social, Behavioral, and Economic Sciences supports research focused on human behavior and how behavior can be shaped by social, economic, political, cultural, and environmental forces. Two NSF-supported researchers, Abigail Marsh, a professor in the Department of Psychology and the Interdisciplinary Program in Neuroscience at Georgetown University and Joshua Greene, professor of psychology and a member of the Center for Brain Science at Harvard University, join us to discuss altruism. What is it? Are first responders altruistic? Are other creatures capable of altruism? If it's on the internet, is it performative?