ABSTRACT
Tipping on the road is just one of a long list of behaviors that are anomalous in this way. We donate anonymously to charity, we return lost wallets to their owners with the cash intact, we vote in presidential elections, and some of us risk our lives to save strangers in distress. Each of these behaviors promotes the larger interests of society. But how could the moral sentiments that motivate individuals have been forged in the crucible of natural selection, which accords primacy to individual material payoffs? In this chapter, I summarize my attempts in earlier work to answer this question (see, e.g., Frank, 1987, 1988, 2004a, 2004b, 2005; see Hirshleifer, 1987, for a closely related argument).
