Wednesday, May 21, 2008

How Did Honor Evolve?

This is an interesting article from the Chronicle of Higher Education:

How Did Honor Evolve?
The biology of integrity

Key quote:

That process, known as "group selection," has a long and checkered history in biological theory. Since natural selection should consistently reward selfish acts, how to explain the existence of morality that induces people to behave, as Bertolt Brecht puts it in The Threepenny Opera, "more kindly than we are"? These days, evolutionary explanations lean heavily on kin selection (also known as inclusive fitness theory, whereby apparent altruism at the level of bodies can actually be selfishness playing itself out at the level of genes), and on reciprocity, essentially "you scratch my back, I'll scratch yours." But there is also the possibility that beneficent acts are biologically generated by a payoff enjoyed by the group, of which the altruist is a member. At one point in The Descent of Man and Selection in Relation to Sex, Darwin gave impetus to the group selectionists:

"Although a high standard of morality gives but a slight or no advantage to each individual man and his children over the other men of the same tribe, … an increase in the number of well-endowed men and advancement in the standard of morality will certainly give an immense advantage to one tribe over another."

But just because Darwin said it doesn't make it true. The problem is that even if people "well endowed" with morality provide their "tribe" with an "immense advantage," those same people run the risk of being immensely disadvantaged within their group if such endowment equates to spending time, energy, or money on behalf of others, or running risks that help the larger social unit while hurting the altruist. As a result, although group selection — along with its companion concept, "the good of the species" — was uncritically accepted for about a century, it has been deservedly out of favor for several decades, displaced by the understanding that selection operates most effectively at the lowest possible level: individuals or, better yet, genes.

Or does it? Maybe reports of group selection's demise have been greatly exaggerated. Various mathematical models now suggest that under certain stringent conditions, selection could (at least in theory) operate at the level of groups. Some of the most promising formulations involve so-called multilevel selection, in which natural selection operates in simultaneous, nested baskets: among genes within individuals, among individuals within groups, among groups within species, and presumably among species within ecosystems, among ecosystems on the planet Earth, and (why not?) among planets in galaxies, and galaxies in the universe.

Received wisdom these days is that if a behavior is costly for the individual, it is unlikely to evolve, regardless of whether it is beneficial for the group or the species. Nonetheless, even if we grant that group selection has probably been inconsequential when it comes to changing gene frequencies, that does not mean that selection at the group level hasn't been instrumental in shaping human psychology, producing some pro-social tendencies via cultural evolution rather than its genetic counterpart. And so we return to honor codes, violators thereof, and those who turn them in.

Read the whole article.

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