ABSTRACT
Humans naturally and quickly divide themselves up into tribes. It’s our team versus your team, our town versus your town, our religion versus your religion, our political party versus your political party, and so on. Further, we tend to favor our in-group over your out-group, often consciously but sometimes unconsciously. We treat out-group members differently, and often unfairly, in part because different parts of our brains judge in-group members and out-group members. Over time, people have generally done a better job of using moral imagination to expand the circle of those who might be considered worthy of being treated as in-group members, but there is much work left to do in this regard.
