Abstract

The rise and fall of societies has traditionally been subject matter for history and sociology, but with The Human Swarm, the author establishes the human society as a legitimate object of study for evolutionary biologists. Societies are different from groups of cooperating individuals in that they have a social identity that sets the terms for group membership. In ant colonies, identity is manifested by a unique scent; in whale pods, by unique sounds; and in human groups, by a wide range of signals, including visual markers, accents, and subtle behavioral cues. Identity is what allows the size of societies to increase without all members having to know each other. Strangers can expect to cooperate relatively easily each other, as long as they share a social identity.