People are altruistic because they are militaristic, and cultured because they are common. At least that is the message of a couple of new studiesSo, war for a civil society?
WO of the oddest things about people are morality and culture. Neither is unique to humans, but Homo sapiens has both in an abundance missing from other species. Indeed, that abundance—of concern for the well-being of others, (even unrelated others), and of finely crafted material objects both useful and ornamental—is seen by many as the mark of man, as what distinguishes humanity from mere beasts.
How these human traits evolved is controversial. But two papers in this week’s Science may throw light on the process. In one, Samuel Bowles of the Santa Fe Institute in New Mexico fleshes out his paradoxical theory that much of human virtue was forged in the crucible of war. Comrades in arms, he believes, become comrades in other things, too.
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Dr Bowles’s argument starts in an obscure cranny of evolutionary theory called group selection. This suggests that groups of collaborative individuals will often do better than groups of selfish ones, and thus prosper at their expense. It is therefore no surprise, according to group-selectionists, that individuals might be genetically predisposed to act in self-sacrificial ways.
This good-of-the-group argument was widely believed until the 1960s, when it was subject to rigorous scrutiny and found wanting. The new theory does not pitch groups against groups, or even individuals against individuals, but genes against genes. It does not disallow altruistic behaviour, but requires that this evolve in a way that promotes the interest of a particular gene—for example by helping close relatives who might also harbour the gene in question. The “selfish gene” analysis, so called after a book by Richard Dawkins, makes good-of-the-group outcomes almost impossible to achieve.
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Dr Bowles has focused the argument on war, since it is both highly collaborative and often genetically terminal for the losers. In his latest paper he puts some numbers on the idea. He looks at the data, plugs them into a mathematical model of his devising and finds a pleasing outcome.
To gather his data, Dr Bowles trawled through ethnographic and archaeological evidence about warfare between groups of hunter-gatherers. This is rarely war in the modern sense of planned campaigns. It is more a matter of raids, ambushes and fights between groups who have met accidentally. It is, nevertheless, quite lethal. Dr Bowles identified eight ethnographic and 15 archaeological studies that met his criteria of reliability and abundance of data. They suggest that 12-16% of mortality is the result of such low-level warfare. This is a figure much higher than, for example, the mortality caused in Europe by two world wars, and is certainly enough to drive evolution. But the question remained of whether it could drive group selection.
It was to test that idea that Dr Bowles devised his model. Although it pitches group against group, it is strictly based on the idea of selfish genes. It looks at the benefit to a notional gene that promotes self-sacrifice. The question is, does such a gene do well if individuals having it belong to a group that takes over the territory and resources of a similar, neighbouring group, but at the risk of some of those individuals losing their life in the process? What is the maximum self-sacrificial cost that can evolve in these circumstances?
In the absence of war, a gene imposing a self-sacrificial cost of as little as 3% in forgone reproduction would drop from 90% to 10% of the population in 150 generations. Dr Bowles’s model, however, predicts that much higher levels of self-sacrifice—up to 13% in one case—could be sustained if warfare were brought into the equation.
Heck, maybe there is more to it than just keeping the bad guys out ... it keeps the good guys good.
However, how does explain the Mongolians?
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