Humans often act for the common good of a group, even when the group consists largely or entirely of nonkin. Normative behavior has been studied by the social sciences for decades, but understanding the underlying basis has become increasingly interdisciplinary. Psychology and neuroscience are studying how such behavior emerges from an inherent human nature. The findings are complex and contrary to some common intuitions. Moral choices often, but not always, spring largely from unconscious sources rather than conscious reflection. Rather than a single moral sense, multiple dimensions are involved, and individual differences along these dimensions can account for much of the conflict that occurs among righteous individuals. Social interaction frequently depends on the recognition of others’ intentions and understanding of others’ beliefs, and science has begun to understand how our brains carry out these tasks. Sometimes moral choices reflect empathy for others, but new research helps to explain the variability of this phenomenon within and across individuals. The emphasis in the symposium will be on advances in basic research, but the work has extraordinary practical importance. The continued prosperity of our species, which will require reaching a sustainable world, will depend on enormous scientific and technological breakthroughs, but also on the degree to which the human capacity to act for the common good can be extended to a global scale.