October 24, 2008
Men are under natural selection to become richer, according to a report in the November issue of American Naturalist. That’s right: the same way natural selection once encouraged longer necks in giraffes and duck bills on ducks (and platypuses), men are now feeling that Darwinian pull toward the corner office.
The Newcastle University researchers found the effect only in men, and explained it by saying that
men strive for cultural goals such as wealth and status in order to convert these achievements into reproductive success.
Women showed the opposite effect: lower incomes were associated with more children (the researchers interpreted this as women giving up earning potential in order to have kids). All sorts of other interesting societal lessons cropped up in the study. The effect held across typical Western societies (the U.K., Sweden), in African hunter-gatherer societies, and in family records of Europeans spanning the last 500 years.
This research is kind of a brutal reminder that civilization doesn’t trump evolution, it just shifts the focus. Quasi-philosophical discussions about whether we’ve stopped evolving are fun, but there’s really only one right answer: Of course we’re still evolving.
Evolution is just the slow genetic shifting of the norms in a population. It happens to the best of species – even ones that have invented flu shots, indoor plumbing, and airbags. Case in point: I have terrible eyesight, but thanks to contact lenses I’ve avoided being eaten by wolves or walking off cliffs. So you might argue that our superb mammalian eyeballs have stopped evolving.
But I’m still childless. If I keel over tomorrow then, evolutionarily, I’ll have vanished.**** My genes will sink into the dirt along with the rest of the contents of my cells. Which of my genetic traits will be to blame? My enormous Anglo-Saxon cranium? The tendency to recite Monty Python on first dates? Too busy blogging to meet real people? Or my paltry earning power?
The point is that natural selection is at work, blindly weeding out genes, even if in less blood-curdling fashion than we often think of it. Of course, selection is only one of evolution’s three ingredients. To actually evolve, a population needs to be variable, different individuals must have differential reproductive success (that’s selection), and they must be able to pass those differences on to their offspring (that’s heritability). But all those are met, the researchers argue: just ask the Kennedys.
Presumably we’re not evolving some kind of Susan B. Anthony-producing sweat gland, of course. But more subtle abilities (or predispositions) to accumulate wealth are being rewarded with more children. And although evolution takes a long time, the results from this study suggest this selective pressure is as old as the barter system. I wonder what exaggerated features it has already produced, giraffe- or peacock-like, in our bodies and our psyches?
(Image: courtesy Matt Schwartz. disclaimer: enormous cranium notwithstanding, that’s not me in the picture)
***Except for whatever I have in common with my nephews and nieces.
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