Are women evolving to be sexier? Or is there selection bias going on?


A post over at Skepacabra’s reminded me of a TED Talks I’d watched a while back with Dan Dennett, wherein he explains why it is we find things sweet, cute, sexy or funny. There’s nothing intrinsic about those objects that makes them so — but we’re wired to think so, because otherwise how the hell would we be encouraged to eat certain things, take care of our babies, mate with others, or do menial tasks?

Video and more babbling below the fold.

Skepacabra’s post relates that a study from Helsinki shows that attractive women have upward of 16% more children than their less attractive counterparts, and that men have the same amount of children regardless of their looks. The natural logical leap is that, given enough time, as attractiveness is a heritable trait, women will evolve to be more beautiful, while men will not, as there is no extra selective pressure going on with them.

What makes me skeptical about this study is twofold. First, we live in a patriarchal society, where men generally get to choose their mates, and women have less say in the matter. Men are expected to make the first move, initiate sex, court the woman, propose marriage, and prove their viability not through physical attributes, but through their ability to maintain the family. This means the selection criteria are different for men — successful intelligent men probably have more kids than unsuccessful ones on average. And successful intelligent men likely tend to make their move on attractive women more often than unattractive women — again, on average. So the selection bias in place is different for men and women to begin with.

Second, our ideals of beauty change drastically over time. Not a hundred years ago, we wanted women with large plump rears, because it meant that they were more insulated and more capable of withstanding the rigors of pregnancy and childbirth in times where resources were more scarce. So women wore large bustles under their petticoats, to enhance their posteriors, indicating fecundity. During the depression, despite the fact that lean and trim (in the mode of what people would today call attractive) was the norm, plump folks were “attractive” because they were more rare and it indicated they had lots of resources. Nowadays we want women who are skinny despite plentiful food, because it says they are so assured of their prosperity that they can afford to eat only the bare minimum for survival without any fear of dying of starvation, and abstain from “storing up fat” for long stretches without food. Because these criteria swing wildly from generation to generation, what we find to be sexy will also change, so what we select for will also change.

So, the study is flawed in its conclusions that women will get “more attractive” over time. We’re hard-wired through millennia of evolution to find what has a better chance of survival, most attractive. Since that changes depending on the environment, and depending on the fashion of the day, any attempt at stating that women are evolving to become more attractive, is deeply flawed.

Comments

  1. says

    Did I just get Mix-a-Rolled? I think I did.

    And it totally proves my point. Even different cultures within the same society have different standards of beauty, as evidenced by the preponderance of hip-hop artists who desire badonkadonks.

  2. cicely says

    If, as I’ve read, ‘beauty’ is partly a side-effect of symmetry of features (whether of underlying structures or because of resilience to environmental factors that might be reflected as asymmetry), I would think that even if beautiful women do out-reproduce less attractive ones, their female descendents wouldn’t be the only beneficiaries; the male ones should ‘go along for the ride’…just as I would expect successful intelligent men to breed “success” and intelligence into their daughters as well as their sons.

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