312 M. Hoffman et al. Conclusion In this chapter we have showed that a single approach-game theory, with the help of evolution and learning—can explain many of our moral intuitions and ideologies. We now discuss two implications. Group Selection. Our chapter relates to the debate on group selection, whereby group level competition and reproduction is supposed to occasionally cause indi- viduals to evolve to sacrifice their own payoffs to benefit the group (e.g., Wilson, 2006). One of the primary pieces of evidence cited in support of group selection is the existence of human cooperation and morality (Fehr & Fischbacher, 2003; Fehr, Fischbacher, & Gichter, 2002; Gintis, Bowles, Boyd, & Fehr, 2003; Haidt, 2012; Wilson, 2010, 2012), in particular: giving in one-shot anonymous laboratory experi- ments, intuitively sacrificing one’s life for the group Gumping on the grenade), and contributions to public goods or charity. However, we have reviewed an alternative explanation for these phenomena that does not rest on group selection. It also yields predictions about these phenomena that group selection does not, such as that peo- ple are more likely to cooperate when they are being observed and there is variance in the cost of cooperation. The approach described here also explains other phenom- ena, such as categorical norms and ineffective altruism. These lead to social welfare losses, which is suboptimal from the group’s perspective. The categorical norm against murder, for example, leads to enormous waste when keeping alive, some- times for years, those who have virtually no chance of a future productive life. Admittedly, despite their inefficiencies, these moral intuitions do not rule out group selection, since group selection can be weak relative to individual selection. But it does provide a powerful argument that group selection is unnecessary for explaining many interesting aspects of human morality. It also suggests that group selection is, indeed, at most, weak. O