In this chapter, Haidt tries to understand what binds people together in groups and how those binds can be advantageous to both community and individual. Haidt begins with his own emotional experiences following 9/11. Though he always identified as a WEIRD universalist and thought of emphasis on the American flag as bordering on jingoism, suddenly Haidt felt a very strong desire to put an American flag sticker on his car. Ultimately, he decided that he could put a flag sticker on his car, as long as the American flag was balanced with a sticker of the UN flag. Despite reaching this internal compromise, still Haidt felt surprised, even rattled, by how intensely group-minded he felt.

Trying to make sense of this experience via cognitive science and psychology, Haidt contends with a central tenet of evolutionary thought. Haidt acknowledges that there is ample proof that survival of the fittest compels individuals to act selfishly, to be motivated by the constant desire for self-preservation and the passing on of genetic material. Human selfishness, Haidt maintains, sometimes manifests itself as groupishness. Though the idea lost popularity in the 1970s, Haidt works to revive the concept of group selection.

The theory of group selection argues that not only do individuals struggle for survival, but groups also compete with one another for rank and resources.