Free An Introduction to Evolutionary Ethics by Scott M. James Page B

of engaging in ongoing cooperative exchanges.
    Trivers' hypothesis was that natural selection seized on mutations disposing individuals to cooperate, if only occasionally. If we assume that, in a particular environment, the cost–benefit ratios are relatively stable and opportunities for cooperation are recurrent, the adaptive pressure is there for a kind of reciprocal altruism to evolve. A genetic mutation that disposes an organism to enter into cooperative exchanges with others will evolve if such exchanges can regularly be preserved. But this is much easier said than (biologically) done. As biologists are quick to point out, the Prisoner's Dilemma (despite its elegance – or perhaps because of it) can distract us from all the intricacies and complexities of real-world exchanges, in both the human and the non-human realms. Perhaps the most apparent point is the fact that single exchanges between strangers with little chance of future interaction are surely the exception and not the rule. Even among nomadic animals, in-group interactions will be frequent and participants familiar. This puts new constraints on how a Prisoner's Dilemma-type game is played. Furthermore, it potentially changes the payoffs for each player. For example, in iterated games there may be future costs associated with defecting when another cooperates that do not arise in single exchanges. (Think of the difference between a situation in which Farmer A “flees the scene” of defection, as in our original example, and a situation in which Farmer A defects but remains in proximity to Farmer B. The latter situation is, you might say, combustible.) In the next chapter we'll explore these details more fully. More specifically, we'll look at the engineering ways in which evolution may have solved the problem of preserving cooperative exchanges – at least in humans. This will move us decidedly into the terrain of the moral.
    2.7 Conclusion
    My aim in this chapter has been to clarify and support the following idea: the theory of natural selection has the potential to explain at least some of the helping behavior we observe in the world. To the extent that human instances of such behavior amount to moral behavior, then evolution can (to that extent) explain a piece of human morality. For example, you might insist that we have strict moral obligations to our family members; this may be evidenced by our strong emotional bond to their well-being. The theory of inclusive fitness, by redirecting our focus to the gene's-eye level, may provide an explanation for why we tend to think that we have these strong moral obligations to our family members: such thoughts, ignited by strong emotions, reliably disposed our ancestors to care for and protect relatives. And by caring for and protecting our relatives we were, in a sense, caring for and protecting copies of our genes. A strong moral commitment to one's family, after all, has high biological payoff.
    Even in the case of self-sacrificing behavior toward non-relatives , evolution may offer some explanation. It may be, on the one hand, that the psychological system put in place by the processes of inclusive fitness is not “fine-grained” enough to distinguish relatives from non-relatives. From the point of view of natural selection, it was good enough that we were attuned to those around whom we live. So in environments where many of the people in your close proximity are not biologically related to you, you may nevertheless see yourself as having a moral duty to protect their well-being, too. On the other hand, self-sacrificing behavior toward non-relatives may be a function of the high value we place on preserving cooperative relationships. We may regard it as a moral imperative to “follow through on our commitments” or to “keep our promises” or to “repay our debts.” But insofar as these attitudes dispose one to preserve cooperative relationships, they serve ultimately to advance one's biological