The creator of the wildly popular blog Wait But Why explores the origins of human tribalism using science, history, and badly drawn comics--and proposes a better way for us all to get along.There's a concerning trend happening in the modern world right now: we're becoming more polarized, more tribal, worse at cooperating, and worse at communicating. Or, said more succinctly, if modern society is like a human, that human seems to be getting younger and less mature each year th