Some years ago, when I first began writing about the evolution of human sociality, a colleague put to me the question: Why are humans still social? That “still” was weighty with meaning—the idea of a primal solitary state, to which humans might return, perhaps finally freed from group living by technological progress. I was dumbfounded. Humans have no choice but to live in groups. They are unable to reproduce and survive to reproductive age without a group, which makes them obligately interdependent. That interdependence is inscribed upon the body. We lack natural defenses such as impressive canines or tough hides. We have an extended, care-intensive infancy. And we have traits, such as omnivory and tool making, that enabled humans to exploit rainforests and tundra, but that create dependence on collective knowledge and cooperative information sharing. Humans are still social because they must be.
