Abstract In biology, the evolution of increasingly cooperative groups has shaped the history of life. Genes collaborate in the control of cells; cells efficiently divide tasks to produce cohesive multicellular individuals; individual members of insect colonies cooperate in integrated societies. Biological cooperation provides a foundation on which to understand human behavior. Conceptually, the economics of efficient al-location and the game-like processes of strategy are well understood in biology; we find the same essential processes in many successful theories of human sociality. Historically, the trace of biological evolution informs in two ways. First, the evolu-tionary transformations in biological cooperation provide insight into how...