Is twerking validated by evolution, too?


We have an exciting press release from the University of Texas! Human evolution has been demonstrated by psychologists! It’s titled Men’s Preference for Certain Body Types Has Evolutionary Roots. Try reading it critically, though, and you discover it’s yet another set of bad studies overinterpreted by evolutionary psychologists.

Why is it always a study that verifies that men like to judge women’s bodies, with the conclusion that this has deep evolutionary significance? They do a good job of gussying it up with sciencey sounding rationales, I will say that for them. They’re looking specifically at the curvature of the spine in the lower back, and how well it projects women’s butts backwards.

“This spinal structure would have enabled pregnant women to balance their weight over the hips,” Lewis said. “These women would have been more effective at foraging during pregnancy and less likely to suffer spinal injuries. In turn, men who preferred these women would have had mates who were better able to provide for fetus and offspring, and who would have been able to carry out multiple pregnancies without injury.”

They say that the optimum curvature of the lumbar spine is 45°. OK, let’s just accept that for a moment. Do they have evidence that having a curvature of 44° or 46° actually affects women’s reproductive ability over their lifetime? Do they have evidence of even one woman who has decided to have one less child in her life because she has a hard time foraging for food with her slightly less curvy spine? Do we have an instance of one man deciding to marry and have children with a woman because her spine looks like it would qualify her for some quality prolonged turnip-picking time?

I am exasperated at the weakness of their premise, but I am appalled at the nature of their research to test their hypothesis. They did two studies.

About 100 men rated the attractiveness of several manipulated images displaying spinal curves ranging across the natural spectrum. Men were most attracted to images of women exhibiting the hypothesized optimum of 45 degrees of lumbar curvature.

Approximately 200 men were presented with groups of images of women with differing buttock size and vertebral wedging, but maintaining a 45.5-degree curve. Men consistently preferred women whose spinal curvature was closer to optimum regardless of buttock size.

Asking a bunch of college men (probably the usual collection of Psych 101 students) to look at pictures of women’s asses is not the way to test that idea. How about these experiments instead?

  • Survey a group of women field workers for back pain, or for health-related absences, and quantify the shape of their lower spine.

  • Examine a cohort of recently married women, and a cohort of unmarried women, and compare their spinal curvature. Is it actually a significant factor in mate choice?

  • Examine hospital records for patients who had difficulty in childbirth. Correlate that with spinal shape.

Unfortunately, those kinds of studies are hard to do; gathering the data is non-trivial, and when you do get it, you’d no doubt discover that there a whole lot of factors other than the shape of their asses that play into the physiological stresses of labor, mate choices, and decisions about having children, and you wouldn’t get the nice, simple-minded answers you’d get from asking a bunch of 19 year olds what shape of ass they like…and which will generate a nicely consistent set of responses conditioned by contemporary pop culture. And then, of course, the investigators will ignore the influence of culture so they can make sweeping statements about biology.

“What’s fascinating about this research is that it is yet another scientific illustration of a close fit between a sex-differentiated feature of human morphology — in this case lumbar curvature — and an evolved standard of attractiveness,” said the study’s co-author David Buss, a UT Austin psychology professor. “This adds to a growing body of evidence that beauty is not entirely arbitrary, or ‘in the eyes of the beholder’ as many in mainstream social science believed, but rather has a coherent adaptive logic.”

Christ. I can concur with the idea that we have a biological preference for some features of our mates: symmetry is a common one, as is general health, and you know, it’s not that far-fetched that we might avoid mating with individuals who show signs of being infested with parasites. But focusing on single parameters like the exact degree of curvature of part of the spine, and insisting that we’re hard-wired in some way to recognize its adaptive value, is incredible bullshit. Especially when the investigators haven’t actually demonstrated the adaptiveness of the feature in question.

And if standards of beauty have an adaptive basis, how does one explain how they vary over time and in different cultures? How does one handle the fact that different men have different standards, so what is beautiful to one may be less so to someone else? How do we account for the fact that women society judges beautiful don’t all look alike?

Easy. Just claim it’s the product of evolution, therefore these guys are right.

This morphology and men’s psychological preference toward it have evolved over thousands of years, and they won’t disappear over night.

“This tight fit between evolutionary pressures and modern humans’ psychology, including our standards of attractiveness, highlights the usefulness that an evolutionary approach can have for expanding our knowledge not just of the natural sciences, but also the social sciences,” Lewis said.

Gaaaah. You can’t just declare that men have had the same psychological preferences over thousands of years on the basis of a survey of contemporary male American college students! The conclusion is unsupported by the evidence! You also can’t just say that evolution would drive the shape towards some kind of engineering adaptive ideal — these are psychologists, have they never heard of superstimuli? And as psychologists, how can they so blithely dismiss the effects of common cultural experiences?

Fucking evolutionary psychologists. They really don’t help my blood pressure at all.

Comments

  1. says

    You know, if there’s one thing I would wish EP cranks would stop doing, it’s using the lens of men’s perception of women as a measure of women’s fitness.

    If there were one thing. Unfortunately, there are a few hundred other things I wish they’d stop doing.

  2. stevenjohnson2 says

    I’d like to add that David Buss, cited above as approving this twaddle, is very commonly hailed as the guy who does the very best EP research. This is symptomatic of the shockingly low level in the field. And, thanks, for a good short refutation.

    I would like to add that whatever the EP folk say when the point is raised, when they do research they always assume natural selection is omnipotent and all traits are adaptive.

  3. Al Dente says

    I rate women’s attentiveness on their liking for radishes. A radish aficionado is incredibly attractive while a radish hater is completely unattractive. I have a theory for this (which is mine). Since in paleolithic times women were the gatherers, any woman who didn’t like radishes was less effective as a food gatherer and would likely cause her band to starve through lack of nutritious radishes. A radish lover would provide more food in the form of radishes, causing her band to flourish.

    Gee, this evo-psych stuff is easy.

  4. Who Cares says

    Speaking of doing it right I remember seeing a similar study (involving relative body proportions) where they took their hypothesis and went into the South American jungle, sub-Saharan Africa and tried to find out if people in very different cultures would go and select the same ones as best.
    Then some serious number crunching and then yes there was a weak correlation after that.

  5. Sastra says

    The cultural factors always include status — who has it and what signals it. This can change dramatically from place to place and time period to time period. I wouldn’t be surprised if there was a genetic tendency to prefer mates with a higher status over a lower one across all primates, not just humans. And factors like preferring big butt vs. little butt seems to me to have little to do with survival and more to do with what a culture sees as indicative of wealth or good breeding.

    I once read that English explorers encountering the lush and curvy female figures on ancient Indian carvings found them repulsive.

  6. mildlymagnificent says

    So what happened to men’s powers of observation during the flapper era. Straight as a broomstick front and back. Women deliberately flattened their breasts to get the right look and garments were cut and sewn to disguise the fact that there was any bum, let alone hips, under the dress at all.

  7. blf says

    Fucking evolutionary psychologists. They really don’t help my blood pressure at all.

    EP™ brands — such as Batshite Insanity and the long popular Males’R’Correct — do make good beds for growing MUSHROOMS! and the smellier sorts of cheeses.

  8. says

    <evopsych>All the manly men who appreciated the sexy ass curve had also, in their manly way, volunteered to fight in WWI, and gotten their ass-loving asses shot. This produced a shift in the frequency of the ass-alleles in the post-war era, leading to a temporary ascendance of wimpy boy-men who imposed their feeble preferences on those accommodating women. Don’t worry, though, since they were breeding the weak together, and their lineages died out, the ass-men strong and true are now back in dominance and favoring 45° but angles once again!</evopsych>

  9. says

    I don’t have any scientific training, but doing EP research seems to be so simple even I could performing it.

    Hypothesis: Posit that a certain trait is not determined by culture, but evolution.

    Experiment: Find said trait in a small group of my neighbors.

    Conclusion: Proclaim that the existence of that trait among my neighbors proves that it is not determined by culture, but evolution.

  10. brett says

    You know how people enjoy sitting in chairs? Clearly this was driven by the propensity of our ancestors to sit on top of animals they had just killed, with people whose butts were most amenable to sitting getting more rest, hunting better, and therefore breeding better! Over time, evolution gradually shaped human beings to have a preference for sitting on stuff as well as butts to do so.

  11. says

    I’ve come to the conclusion that we need to pound neutral theory (among numerous other things) into a lot of people’s heads. Yes, adaptationism explains a lot. No, that doesn’t mean any given feature was the result of adaptation.

    It’s a tempting line of thought, and I’m embarrassed to say I still got caught in some of it while watching a flock of flamingos on TV with my parents.

    Me: “Why are flamingos pink? What’s the advantage of being hot pink?”
    Dad: “They’re pink because of their diet, not their genes.”
    Me: “Oh, right. I forgot all about that.”

  12. david says

    What would Buss say: the male spine is curved with a lordosis that is about the same as the female spine.

  13. Cuttlefish says

    The perfect ass is, science sees,
    Precisely forty-five degrees,
    Cos ancient cave-bros made pursuit
    For tushes that they deemed … acute.

    Oh, how the web of science tangles
    When first we try to play the angles;
    The authors, playing fast and loose,
    Are seen as asses. And obtuse.

  14. grendelsfather says

    I forgot who said this first, but it seems like the characterization of EP as “the field of psychology that tries to justify why it is OK for 50 year-old professors to boink their 25 year-old graduate students” is just about right.

  15. says

    I used to read a lot of this crap when I was helping my late wife with her research. Seeing David Buss’ name on a paper was pretty much a guarantee of crap in, crap out.

  16. says

    What do they think happened with all the not perfect ass women? They didn’t mate? They didn’t mate the top mamoth hunters?
    It’s also telling that apparently to our ancestors, nothing ever mattered except the ability to pop out children. It seems unthinkable that a prehistoric guy could e drawn to a prehistoric woman because of some other talent or quality she had.

  17. M can help you with that. says

    Andrés Diplotti @ 9 —

    My thoughts exactly. When there are two competing hypotheses for the cause of a phenomenon — “Feature X is determined genetically and was selected for” vs “Trait X reflects social preferences and/or indoctrination and/or ideology in this set of cultures” (or “there may be an evolved or instinctive component, but it’s heavily moderated by sociocultural experience”) — so many EPers seem to think that demonstrating “Trait/feature/difference X does, in fact, exist to some extent” is evidence for their hypothesis regarding X over the competing hypotheses.

    Would they accept the same logic if it were done by the other side? “We hypothesize that heterosexual male American college students prefer women with breasts in this size range because they’ve grown up with that being the standard of attractiveness. We have demonstrated that heterosexual male American college students do, in fact, prefer women with said breast sizes. We’ve demonstrated that it’s all cultural!” I mean, the conclusion here is one that could probably gain great support based on all available evidence…but this hypothetical study would do nothing for that. So why do so many bad-but-popular EP researchers have that basic failure of logic?

  18. neverjaunty says

    Isn’t that the same David Buss who lost his shit when a group of evolutionary psychologists, studying attitudes among Chinese men, cast doubt on his theory that men more disturbed by their SOs having sex than falling in love with someone else whereas women were of course the opposite? IIRC, when the New York Times contacted him for comment on that study he ranted about how the researchers were ‘fifth columnists’ and not true evo-psychs.

    http://www.slate.com/articles/health_and_science/medical_examiner/2005/08/cave_thinkers.html

  19. Al Dente says

    Giliell @17

    It seems unthinkable that a prehistoric guy could e drawn to a prehistoric woman because of some other talent or quality she had.

    Like radish gathering! </snark>

    It amazes me that someone will decide “my undergraduate male students like X in women, therefore paleolithic males preferred women with X because of some reason I pulled out of my ass” is a reasonable basis for research.

  20. Hoosier X says

    Is evopsych a pseudo social-science or a social pseudo-science? And how would the designation change if you moved the hyphens or took them out entirely?

  21. Radioactive Elephant says

    This morphology and men’s psychological preference toward it have evolved over thousands of years, and they won’t disappear over night.

    Well, that’s subtle.

  22. vaiyt says

    The lack of historical perspective… it hurts…

    “This spinal structure would have enabled pregnant women to balance their weight over the hips,” Lewis said. “These women would have been more effective at foraging during pregnancy and less likely to suffer spinal injuries. In turn, men who preferred these women would have had mates who were better able to provide for fetus and offspring, and who would have been able to carry out multiple pregnancies without injury.”

    Where are the Wikipedia editors to slap a big [CITATION NEEDED] on this shit? This is textbook “assumes facts not in evidence” if I ever saw it.

  23. twas brillig (stevem) says

    re Hoosier X @25:

    Is evopsych a pseudo social-science or a social pseudo-science?

    Good question, they certainly give much evidence of …pseudo…
    The OP showed us another crass example of bad-Evopsych. Gosh. Evopsych must be a real science; our psychological responses to reality must have been a product of evolution, as our brains evolved.
    It seems, so far, that all their experiments result in “just so…” explanations. I think it was Desmond Morris (Descent of Man) that postulated that women have bouncy breasts to emulate their buttocks, to make men more lustful for them. (given the evolutionary adaptation to frontal, rather than counter-frontal ~~~)
    PZ gave many examples of how to do these experiments a little more rigorously. Are the evopsychs presented here outliers, or typical. I hope they’re the former and not the latter.

  24. lindsay says

    Well, I’m at the right place to ask this, I think. I was under the impression that, overall, more women end up reproducing than men. Is that right, or is that an erroneous idea that I picked up somewhere? If it is correct, wouldn’t that mean that little nitpicky details like female spinal angle-osity don’t matter much?

  25. chigau (違う) says

    Desmond Morris wrote The Naked Ape amongst many others.
    (I thought he was dead!)

  26. enki23 says

    Wait… what the fuck evolutionary advantage would a male of nearly *any* species achieve by withholding sperm from *any* willing female (barring the ones that pay a high price for mating, obviously.) Was there some physiologically high cost to semen spillage in our recent evolutionary past? How the fuck did that work? Or is this some sort of superpowered new form of group selection in which all the individual males sacrifice chances to spread their genes in order to purify the gene pool of slightly different spinal curvatures?

  27. twas brillig (stevem) says

    re chigau (違う) @30&31:
    Thanks for correcting my misattribution@28. Sorry for the incorrect juxtaposition of author&book. Naked Ape. that I cited, was the one with the “just so” stories that the evopsychs seem to be emulating.

  28. Holms says

    A look at a small selection of women’s ideal body types throughout history… somehow, the variables seem to differ much much more so than just a degree here or there in the lower back. Strange, I would call this a blatant case of the nooise being vastly greater than the signal, but apparently evolutionary psychologists are just too darn smart to be foiled by something so petty as data.

  29. says

    How much do the EP researchers examine women’s behaviour? It seems most of the crappy research PZ has discussed has revolved around men.

  30. chigau (違う) says

    twas brillig
    It’s OK.
    Desmond Morris is a knob.
    .
    timgueguen
    Women do behaviour?
    I thought they were props.

  31. footface says

    Daz @ 34 beat me to it: for this explanation to make sense wouldn’t you also need to demonstrate that males were able to tell the difference between a spinal curvature of, say, 44.5° and one of, oh… 45.1° in a natural setting in natural circumstances?

  32. says

    No, women didn’t do behaviour. They also never had anything to say about whom to fuck. That’s why you can’t be too harsh on men who rape. If they didn’t do their job of impregnating unwilling women, we’d have died out looooooong ago. Because women never get horny and never want to fuck and also never want children.
    Except when Evo Psych needs to justify some other bullcrap, like why men need big cars (to impress the feeeeeeemales) or all want to be stay at home mummies and so on. Then women do all the choosing.

  33. opposablethumbs says

    No no, Giliell, even then silly wimmenz (sorry, feeeeeemales) don’t do any actual choosing – it’s all hormones and instincts and biological imperatives, dontchaknow. It’s not like they do any thinky stuff, after all!

  34. rietpluim says

    I just measured my wife’s spinal curve. 43.4 degrees. I feel so less manly now.

  35. UnknownEric the Apostate says

    Sounds like they forgot their key evidence citation:
    “Baby’s Got Back
    By: Mix-a-lot, et al.
    Def American Recordings
    1992

    Their next paper is “Putting Them On The Glass From An Evolutionary Perspective.”

  36. drst says

    Grrrr. I HATE evopsych so much. So much bullshit everywhere on every damn level.

    Where’s the “in depth” studies of a group of women and their preferences regarding penis sizes? Or shoulder to waist ratio in males? I’m pretty sure I could round up 100 women to conclude that all men everywhere if they want to mate have to have Chris Evans’ shoulder-to-waist ratio because SCIENCE!

  37. opposablethumbs says

    Where’s the “in depth” studies of a group of women and their preferences regarding penis sizes? Or shoulder to waist ratio in males? I’m pretty sure I could round up 100 women to conclude that all men everywhere if they want to mate have to have Chris Evans’ shoulder-to-waist ratio because SCIENCE!

    That should be published. Could be pretty funny … :-)
    Preferably with simultaneous publication of identical papers PROVING!!1!!!11!! the superiority of several different ratios, using samples of a few dozen women each time. The authors and the rest of the wording to be absolutely identical.

  38. drst says

    opposablethumbs @ 46 – yeah I should’ve become an evopsych professor. I could’ve put together all sorts of slapdash stuff and gotten it published, gotten tenure and had a nice cushy life, clearly.

  39. Skip White says

    Gah. My advisor in college taught social psychology and evo psych, and essentially worshipped the ground David Buss walks on, and I think had him as his graduate advisor. At least we got to take field trips to the AMNH in New York and the Holocaust Museum in DC. Still didn’t make up for the fact that the entirety of the grade for each class was based on the midterm and final exams, which were mostly just regurgitating information.

  40. John Horstman says

    What’s fascinating to me is that human populations that moved away from Africa actually selected against their supposed optimal spine curvature. The “Black women with big butts” stereotype is likely based on the higher average spinal curvature of women with recent African ancestry, according to a class lecture I attended, which does increase the protrusion of the buttocks. If this is indeed true (I don’t remember the cited source, as this was several years ago – it could have been BS), then the actual evolutionary evidence – observed selection in a majority of geographically-isolated human population groups over thousands of years – contradicts the claim, and rather trivially at that.

  41. Anton Mates says

    I was under the impression that, overall, more women end up reproducing than men. Is that right, or is that an erroneous idea that I picked up somewhere?

    It depends on the society. In the US, the percentages of each gender that end up reproducing are basically identical (86% for women, 84% for men). I believe that’s the case for most Western societies.

    Highly polygynous societies tend to have a larger fraction of childless men (and more men that die early). However, polygyny in hunter-gatherer societies tends to be accepted but rare; very few men amass enough wealth to keep multiple wives. So we were probably mostly monogamous for most of our recent evolutionary history.
    …except of course that that’s social monogamy, and doesn’t tell you whether Mr. Mighty Hunter was fathering twenty kids with his wife plus ten other guys’ wives. And paternity-testing a representative sample of children is extremely difficult to pull off in most societies, for obvious reasons of cultural acceptability and participant safety.

    If it is correct, wouldn’t that mean that little nitpicky details like female spinal angle-osity don’t matter much?

    I believe the evo psych rationale is that, while a woman can easily arrange to be impregnated by some man, her reproductive success is higher if the father provides lots of resources to her and her offspring. And men, for their part, will impregnate anything that moves but will only commit long-term care and resources to a particularly healthy/fertile woman.
    So hawt ladies with optimal spinal curvature can land a rich man, and unhawt ladies have to get knocked up by some loser, basically. And the hawtest and cleverest of ladies will land a rich man but get knocked up by his strapping, handsome pool boy. After which the rich man will go mad with jealousy and try to kill everyone involved. Science!

  42. congenital cynic says

    Actually, I totally believe that research. As a straight man I absolutely prefer the human “body type” that has a vagina. I mean, DUH!?!
    Sure, fit men look good, and I suppose a nicely sculpted penis is attractive, and I can appreciate it for that, but I’m pretty much sold on the vulva. So there. And a word to the people who make beer commercials, I don’t care how big the breasts are.

  43. The Mellow Monkey says

    John Horstman @ 49

    The “Black women with big butts” stereotype is likely based on the higher average spinal curvature of women with recent African ancestry, according to a class lecture I attended, which does increase the protrusion of the buttocks.

    Steatopygia [WIki link with nude photography] is real, not the result of spinal curves. Some groups of people are simply more prone to larger fat deposits in the gluteal region than others. I inherited the flat ass genes while my sister did not and no matter how I arch my back, that ain’t changing.

  44. =8)-DX says

    As a layman, it seems to me that painstakingly studying the perceptions of the group of people you belong to and then attempting to generalise that result to fit a broad range of your personal notions of how the world works isn’t science, it’s projection. In fact it’s classic tribe mentality: people like me think X so X must be true and that’s why we make big fight to steal big bum women from bad mammoth hunter tribe! ME SAVAGE! ME NO LONGER BETA, ME .. AAAAAARGH (and dx is unmercilessly dragged whimpering by the ear to the cabbage patch.)

  45. =8)-DX says

    Shucks *mercilessly. There must be some evo-sexiness to my tpyos, I mean I’ve reproduced already!

  46. llyris says

    @ Anton Mates #50.
    Why assume that ancient people were monogamous because they didn’t amass wealth? What about the possibility that both men and women had multiple partners? Since tribes have a tendency to share.

  47. enki23 says

    I hate to say this again, but I feel like this is being ignored. And it seems kind of important, at least to me.

    1) Under normal circumstances, males have almost no cost to breeding a willing female. Except perhaps under conditions of rampant STDs or something similar. Or under highly artificial conditions that would almost have to have been imposed by other humans. Male apes, like most animals, just don’t lose anything significant having sex with a woman. Females pay a high cost, sure. But males don’t.

    2) Purely in terms of spreading one’s genes, so far as I understand this, and given that there is no real cost to a male, there is nothing to be lost in attempting to impregnate even the most unfit female. It’s like Pascal’s Wager, only about real things. Even if the chances of success are small, the cost to you is virtually nonexistent. If other males were avoiding the females, that’s even better! Males that ignored the supposed preferences and just attempted to breed with everybody would have increased reproductive success.

    3) Because of the above, I would expect any such male preference would, except under some incredibly unlikely circumstances, be strongly selected against.

    4) Any arguments against would, as far as I can tell, have to rely on group selection. Extreme, weird group selection. In which, I guess, the species would have actively guarded against unfit females being bred. Or killed them, I guess, which seems far more likely (not saying much there, but at least it would be vaguely plausible). Thing is, that would be artificial selection. Primitive eugenics. That’s the only way I can see that even the very basic premise of this guy’s bullshit would even be *possible*.

  48. enki23 says

    Edit: “Male apes…… having sex with a female.”
    (I was tripped up going back and forth in my head between humans and our near evolutionary antecedents, not imagining interspecies relations à la crocoducks.)

  49. Brony, Social Justice Cenobite says

    I hate this shit.

    I’m the person with the mental condition that I think is actually inherited emotional programming, and I’m trashing lots of writing because I know I can’t put the neutral unbiased picture together properly yet. I’m agonizing over the bias problem.

    These people are being paid to do what I wish I could be doing, and had to give up (working in research more broadly, not just the writing). This makes me feel thing about humanity that I don’t know what to do with.

  50. =8)-DX says

    @enki23 (various)
    Well, I guess the problem is that with humans there have for a long time been “conditions imposed by other humans.”, in other words all that stuff about owning women as property, and men in power having harems/concubines/multiple wives or just human pair-bonding and child-rearing in general.
    Men haven’t had zero cost from impregnating *any* woman for a very long time, and not just due to the actions of the women.