Sam Bowles talks to Jim about his book, A Cooperative Species: Human Reciprocity and Its Evolution, co-authored with Herbert Gintis. They start by exploring cooperation in hunter-gatherer living: how human cooperation is different from other species', collaboration needed for big game hunting, egalitarianism & competition, hierarchy myths, impacts of weapons, how far cooperation goes back in history, the size & make-up of cooperative groups, altruism, and prerequisites for group selection. They then talk about collaboration in cultures more broadly: the wonder of nationalism, the pros of external threat, cultural progress, leadership, paradoxes of the prisoner's dilemma, differences in cultural cooperation, the "civilizing force of markets", game theory, punishing free-riders, the limitations of unconditional generosity, and more.