Steven Pinker -- How the Mind Works - Hampshire High Italian ...

Hotheads | 397tude, make us want to help them. To understand these emotions, we firsthave to understand why organisms should be designed to help or to hurtone another.Having seen nature documentaries, you may believe that wolves weedout the old and weak deer to keep the herd healthy, that lemmings commitsuicide to prevent the population from starving, or that stags raminto each other for the right to breed so that the fittest individuals mayperpetuate the species. The underlying assumption—that animals act forthe good of the ecosystem, the population, or the species—seems to followfrom Darwin's theory. If in the past there were ten populations oflemmings, nine with selfish lemmings who ate their groups into starvationand one in which some died so that others might live, the tenthgroup would survive and today's lemmings should be willing to make theultimate sacrifice. The belief is widespread. Every psychologist who haswritten about the function of the social emotions has talked about theirbenefit to the group.When people say that animals act for the good of the group, theyseem not to realize that the assumption is in fact a radical departurefrom Darwinism and almost certainly wrong. Darwin wrote, "Naturalselection will never produce in a being any structure more injurious thanbeneficial to that being, for natural selection acts solely by and for thegood of each." Natural selection could select groups with selfless membersonly if each group could enforce a pact guaranteeing that all theirmembers stayed selfless. But without enforcement, nothing could preventa mutant or immigrant lemming from thinking, in effect, "To heckwith this! I'll let everyone else jump off the cliff, and then enjoy the foodthey leave behind." The selfish lemming would reap the rewards of theothers' selflessness without paying any costs himself. With that advantage,his descendants would quickly take over the population, even if thepopulation as a whole was worse off. And that is the fate of any tendencytoward sacrifice. Natural selection is the cumulative effect of the relativesuccesses of different replicators. That means that it selects for the replicatorsthat replicate best, namely, the selfish ones.The inescapable fact that adaptations benefit the replicator was firstarticulated by the biologist George Williams and later amplified byRichard Dawkins in The Selfish Gene. Almost all evolutionary biologistsnow accept the point, though there are debates over other issues. Selectionamong groups is possible on paper, but most biologists doubt thatthe special circumstances that let it happen are ever found in the real