Even… more… ludicrous teleology from evolutionary psychologists

November 9th, 2007 by Ben Goldacre in bad science, evolutionary psychology, mail, telegraph, times | 40 Comments »

If academic funding was determined by newspaper coverage we would never research anything but MMR and evolutionary psychology.

Which is fine.

But if you’re going to tell teleological “just-so” stories about human behaviour, then you could at least make an effort, and try to maintain a degree of internal consistency. Today yet another puddle of ropey evolutionary psychology splashed onto the news pages.

“Women walk more sexily when they are at their least fertile,” say the Telegraph, reporting on a study where men rated the sexiness of women’s walks. The finding, I’m sure, is valid (here is the original paper), but it’s the explanation I’d be dubious about.

Becase there’s always an answer with evolutionary psychologists, whether they’re giving a tidy reductionist explanation about Pink for girls and Blue for boys, or confidently announcing that in the future, all men will have big willies.

So how does Dr Meghan Provost, evolutionary psychologist of Mount Saint Vincent University in Nova Scotia, wriggle out of the counterintuitive finding that women are most hot when they are least fertile?

The Daily Mail pick up the thread: “The apparently contradictory finding – which belies earlier evidence that women’s behaviour becomes more alluring around the time of ovulation – amounts to an evolutionary con-trick on men, scientists said yesterday.”

“Genuine signals of sexual availability, such as subtle changes in smell and facial expressions, can be detected only close up.” The Times continue (the papers absolutely love this stuff): “If she flaunts herself too openly at fertile times, she could be made pregnant by an unsuitable man,”

Fine. Neat. Perfect. Everything fits when you find your hypothesis in your results.

So maybe someone can explain to me how this finding is consistent with this paper from 2006 on how women “drrrress to impress” when they’re fertile?

Or how it fits in with these findings from the current edition of the journal Evolution and Human Behaviour, showing that lapdancers tips are at their highest when the stripper is ovulating.

Maybe a sexy walk is too obvious? Maybe lapdancing in arousing clothing is “a genuine signal of sexual availability, such as subtle changes in smell and facial expressions, which can be detected only close up.”

I’ll have to let my girlfriend know.


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40 Responses



  1. emilypk said,

    November 9, 2007 at 3:02 pm

    To be fair the lap dancing one is a difference case because the behaviour is done for money not to attract mates, and the men may pay more at that time because the smell the hormones (or whatever) not because the dancing is ‘sexier’.

  2. Ben Goldacre said,

    November 9, 2007 at 3:05 pm

    nice, i like the way you’re thinking, although i’m not sure the study design would have left that much room for pheromones to have an influence: nightclub, crowd, smoke, selection of dancer at a distance? don’t know, i don’t, er, go to these places.

  3. cat said,

    November 9, 2007 at 3:52 pm

    Sure you don’t. Just like you don’t read The Daily Mail.

  4. Joanna Moy said,

    November 9, 2007 at 4:14 pm

    I have to confess that I have something of a love-hate relationship with Evolutionary Psychology. It’s such a potentially fascinating area (although I’m not really sure of the worthiness of studies into whether girls prefer pink or how much women swing their hips) but all too often it seems to result in the cart leading the horse… people designing and interpreting experiments in order to justify the pre-conceptions about human behaviour (and in particular human sexual behaviour). Grr.

  5. rob said,

    November 9, 2007 at 4:43 pm

    I do wonder how much of this is due to pressure from journals to not only present results but to explain them. Certainly in my field (astronomy), it’s not enough to say “here’s what the thing looks like” – no matter how tricky doing the work is. You’ve got to also be a theorist and think of reasons why it should look like that, otherwise you can’t get published. And, as observational astronomers aren’t theorists, some theorist then publishes another paper looking at our results and saying why our theory was wrong.

  6. elem said,

    November 9, 2007 at 5:50 pm

    Hmmm…not too sure about this denigration of evolutionary psychology. I’m sure Ben is admirally knowledgable about the subject, but my fear is that readers who are not may begin to think that “evolutionary psychology” is no different from something like “homeopathy”.

    Granted, I’m only a third year psychology student, but the evolutionary psychology we are taught is hugely useful in understanding behaviour, and the vast majority of it applies to animals rather than humans. Certainly our lecturers are quick to encourage us to think critically about evolutionary claims, and to point out that attempting to link human behvaiour with genes is an area fraught with potential confounds (and, as Ben rightly points out, circular arguments).

    I couldn’t agree more in terms of how the media reports this stuff, but I don’t think evolutionary psychologists in general should all be tarred with the same brush.

    Am I overreacting here?

  7. Ben Goldacre said,

    November 9, 2007 at 6:08 pm

    couldnt agree more, ev psych has the potential to be really interesting. i’m not sure it was the media who were at fault here though, it was the author who gave the interpretation which seems highly unlikely to me, in the context of other research findings. and may i say what a pleasure it is to have a posting from the singer of one of britains finest dodgy goth bands, ms jo violet moy?

    www.myspace.com/screamingbansheeaircrew

  8. tomrees said,

    November 9, 2007 at 6:17 pm

    Clearly there is an evolutionary imperative at work here. Only those evolutionary psychologist who dream up spurious explanations get their work featured in print and blogs, and so gain the fame and funding that enables them to attract mates and care for their offspring.

    OK, I’ll get me coat…

  9. RS said,

    November 9, 2007 at 6:46 pm

    Heh, it’s a great paper I don’t know what you’re talking about.

    My favourite bit is this:

    “Late follicular walks had a similar attractiveness level (M = 3.66, SD = .5) as walks recorded in the luteal phase of the menstrual cycle (M = 3.56, SD = .5) when compared with a paired t-test”

    Don’t see that bit in the papers though.

  10. aphasia said,

    November 9, 2007 at 8:12 pm

    @elem

    I think you are overreacting a little bit. I mean it’s a pretty specific instance being brought to attention so it’s certainly not tarring every evolutionary psychologist with the same brush. Just because it’s on badscience.net doesn’t mean that readers will equate the field with homeopathy. I like the fact that this site has quite a wide remit, in that it looks at claims to do with wacky stuff like homeopathy and “mainstream” science like pharmacology etc.

  11. clobbered said,

    November 9, 2007 at 11:10 pm

    The problem with this stuff is how do you test your hypothesis? The lack of an obvious answer is one of the reasons it all seems a bit… non-sciencey.

    See, I can say that the reason women walk more sexily when they are non-fertile is because human females need to not just mate, but retain the male to help rear their offspring, which means they need to keep him interested even when they are not fertile.

    Probably bollocks, but who’s to prove me wrong?

    Other things that don’t help with the apparent scientific credibility of this kind of research is:

    – The fact that everybody thinks they can play this game (as opposed to, say, quantum mechanics, which clearly only “real scientists” can play)

    and

    – Frankly, I am dubious about how repeatably measurable some of these quantities (such as attractiveness) actually are. Mental images of a bunch of men muttering “phwoar” to a stack of pictures/videos do not help.

    and

    – Even if these quantities are measurable in a meaningful way, I am not at all convinced they prove what they say they prove. Most women I know did not mate with the most attractive person they have ever met even if they had the opportunity – perhaps he was unemployed, or a member of the BNP, or an arrogant jerk. Most men I know either behave as the women described above, or would take an opportunity to hop into bed with anything willing, regardless of super-subtle social signals like that.

    So to recap, nobody knows what it means, why it would mean what it means, and why it would matter.

    It really is difficult to take this stuff seriously even before the press gets their hands on it.

  12. Ben Goldacre said,

    November 9, 2007 at 11:12 pm

    i think the problem is they find their hypothesis in their results…

  13. Quixotematic said,

    November 9, 2007 at 11:45 pm

    Has anyone actually read any serious EP other than the goofier studies which catch the eye of journalists? Not a sound sampling policy. I really must get around to reading some myself . . .

    Seriously though, once you accept evolution through natural selection, there is a certain inevitability about EP, unless you resort to special pleading for your immortal soul.

    It is perforce mostly speculation as experiments are a bit of a problem but I’m not sure that the concept deserves the amount of flack it gets from all sides.

  14. Ben Goldacre said,

    November 9, 2007 at 11:57 pm

    i read the cosmides and tooby stuff about ten years ago when it was hip. this looks alright as a starter pack

    www.psych.ucsb.edu/research/cep/primer.html

  15. Victoria said,

    November 10, 2007 at 12:04 pm

    The way I walk is heavily influenced by which shoes I’m wearing and how long I’ve been on my feet for. Extrapolating heartily from this test group of 1, I conclude that this research probably didn’t take all relevant factors (otherwise known as ‘real life’) into account.

  16. emilypk said,

    November 10, 2007 at 3:02 pm

    I think there is a difference between evolution-based theories and evi-opathy (also called ‘just so stories’). The former either perform experiments or acknowledge the descriptive nature of the work and adapt the method accordingly? (i.e. by braiding multiple strands of supportive evidence and looking for counter-evidence and more parsimonious explanations…)

  17. Robert Carnegie said,

    November 11, 2007 at 1:18 am

    If choice of shoes depends on the hormonal cycle then…

    Hey, remember the one about drivers steering measurably clearer of a cyclist with female appearance, does that confound? Then again, it was actually a male researcher in a wig and he may have been giving confusing signals… and not “wiggling” the same way.

  18. mjmanning said,

    November 11, 2007 at 1:45 am

    There’s a great paper on EP (Todd Grantham and Shaun Nichols, “Evolutionary Psychology: Ultimate Explanations and Panglossian Predictions”, in V. G. Hardcastle ed., *Where Biology Meets Psychology*: no online reference I’m afraid) which points out that EPers get their methodology exactly the wrong way round. They infer current cognitive structure from assumptions about past selective environments and then desperately search for evidence that that structure is indeed present. In evolutionary biology proper things go the other way round: get a grip on current function and then attempt to infer selective history. Why are human minds special? This is just one of the many, many problems with some of the work going on under the EP banner (not all of it I hasten to add: this research doesn’t make the mistake of thinking EP is a predictive science–but it’s equally bad).

  19. Diddler said,

    November 11, 2007 at 4:54 pm

    Can we avoid tarring all evolutionary psychologists with the same wacky pseudo-science brush? There is definitely good and bad Evolutionary Psychology work out there and the frequent nutty over-extrapolation of a fringe paper is more indicative of how broadly the term evolutionary psychology is used than proof that the whole discipline is standing on fundamentally shaky ground.
    However, having said all that that I think that there is a worrying number of people using a cartoon image of evolution instead of facts. For a good critique of the discipline read David Buller’s “Adapting Minds: Evolutionary Psychology and the Persistent Quest for Human Nature”. The biggest assumption of all is the assumption that all fundamental behavioral adaptation took place in the Pleistocene. There’s nothing wrong with using evolution to look at human behaviour, it just needs to be grounded in a proper biological understanding of evolution

  20. elem said,

    November 11, 2007 at 10:55 pm

    For those interested in EP, some of the EP stuff on women’s waist to hip ratios and how they influence men’s attractiveness ratings is really interesting (one random example dx.doi.org/10.1016/j.paid.2006.12.003) because WHRs within the “ideal” range (from memory this is 0.7-0.8) correlate with various health-related outcomes, such as risk of diabetes and CHD, and also with factors related to fertility (even, if memory serves me, an endo-cervial ph level that favours sperm penetration!).

    I won’t pretend to understand any of the biological stuff, but if such a visual indicator of a woman’s fertility and health (itself an indicator of good genes) does exist, then evolutionary theory predicts that men should find women who posess that feature more attractive than those who don’t (those of our ancestors who didn’t had, on average, fewer children, so passed on fewer copies of the gene that codes for that preference*).

    That is what Singh and others found, that – all other factors being equal – men preferred pictures of women with this ideal WHR. Clearly a great many other factors will also affect ratings of attractiveness.

    To me, this is a fairly persuasive piece of evidence that evolutionary pressures have shaped our behaviour to some degree, even if it is that range of behaviour which seems to belong to our animal past rather than that which marks us out as human.

    Luke

    * I know it’s not likely to be one gene, but for the sake of clarity etc…

  21. elem said,

    November 11, 2007 at 11:06 pm

    @aphasia

    I don’t really mean that readers will equate ev psych with homeopathy because it is on badscience.net per se, but I do feel that sentences such as:

    “Becase there’s always an answer with evolutionary psychologists, whether they’re giving a tidy reductionist explanation about Pink for girls and Blue for boys, or confidently announcing that in the future, all men will have big willies.”

    …would benefit from a more qualified “*some* evolutonary psychologists”. I don’t think for one second that Ben is misrepresenting or doesn’t understand ev psych, and wouldn’t want to give that impression, nor do I think that many readers would take that from his words, I just feel that some readers, who may never have heard of ev psych before, might.

    I’m being hugely pedantic here, it was merely a mild impression I picked up from this and from one or two other recent entries on the subject.

  22. Ben Goldacre said,

    November 11, 2007 at 11:39 pm

    elem. even cosmides and tooby called whr=0.7 an “emerging academic legend”.

    www.jeremyfreese.com/docs/FreeseMeland%20-%20SevenTenthsIncorrect.pdf

    even the wiki page on WHR has a list of references of transcultural findings where WHR is not 0.7

    en.wikipedia.org/w/index.php?title=Waist-hip_ratio&oldid=154515358

    “In other cultures, preferences vary,[8] ranging from 0.6 in China,[9] to 0.8 or 0.9 in parts of South America and Africa,[10][11][12] and divergent preferences based on ethnicity, rather than nationality, have also been noted.[13][14]”

    # ^ Fisher, M.L.; Voracek M. (June 2006). “The shape of beauty: determinants of female physical attractiveness.”. J Cosmet Dermatol 5 (2): 190-4. PMID 17173598. Retrieved on 2007-08-04.
    # ^ Dixson, B.J.; Dixson A.F., Li B., Anderson M.J. (January 2007). “Studies of human physique and sexual attractiveness: sexual preferences of men and women in China.”. Am J Hum Biol 19 (1): 88-95. PMID 17160976. Retrieved on 2007-08-04.
    # ^ Marlowe, F.; Wetsman, A. (2001). “Preferred waist-to-hip ratio and ecology”. Personality and Individual Differences 30 (3): 481-489. Retrieved on 2007-08-04.
    # ^ Marlowe, F.W.; Apicella, C.L. and Reed, D. (2005). “Men’s Preferences for Women’s Profile Waist-Hip-Ratio in Two Societies”. Evolution and Human Behavior 26: 458-468. Retrieved on 2007-08-04.
    # ^ Dixson, B.J.; Dixson A.F., Morgan B., Anderson M.J. (June 2007). “Human physique and sexual attractiveness: sexual preferences of men and women in Bakossiland, Cameroon”. Arch Sex Behav 36 (3): 369-75. PMID 17136587. Retrieved on 2007-08-04.
    # ^ Freedman, R.E.; Carter M.M., Sbrocco T., Gray JJ. (Aug. 2007). “Do men hold African-American and Caucasian women to different standards of beauty?”. Eat Behav 8 (3): 319-33. PMID 17606230. Retrieved on 2007-08-04.
    # ^ Freedman, R.E.; Carter M.M., Sbrocco T., Gray J.J. (July 2004). “Ethnic differences in preferences for female weight and waist-to-hip ratio: a comparison of African-American and White American college and community samples”. Eat Behav. 5 (3): 191-8. PMID 15135331. Retrieved on 2007-08-04.

  23. elem said,

    November 12, 2007 at 1:01 am

    @ben

    I don’t have the source for the original “academic legend” quote, but the context of the article you link to is measurements of Playboy and Miss America centrefolds. This is not really what I was talking about – certainly I didn’t suggest that WHR is either the only or the most important determinent of men’s attractiveness ratings of women. It would be easy to produce a list of the physical features of women that men are attracted to apart from the ratio of waist to hips (all at the mercy of cultural variations), and I don’t think the pages of Playboy are where you’re likely to find these features best controlled for!

    The same argument (that factors other than WHR were judged) can be applied to cross cultural research into male preferences. For example, from the references you cite, Freedman et al (2004) note in their discussion that the figures used were confounded for hair style and BMI, amongst others.

    Marlowe et al (2001) presented line drawings of white, western women in bathing costumes to Hadza hunter-gatherers, so problems there with ecological validity.

    By 2005, Marlowe et al (with the same Hadza tribesmen) used different stimulus figures and found agreement, noting “…these results imply there is less disparity between American and Hadza preferences for the actual WHR of real women. We suggest men’s preferences vary with the geographic variation in the shape of women who have wider hips in some populations and more protruding buttocks in others.”

    Dixson et all (2007) found that men in Cameroon prefer a WHR of 0.8 (the range I stated in my original post was 0.7 – 0.8).

    I honestly haven’t cherry-picked the references you mention, I just went through them at random. I don’t think the references on wikipedia apparently showing cultural variations really show that when you examine the methodology in enough detail, unless you assume that the original work insisted upon a WHR of exactly (or nearly) 0.7, which it didn’t.

    Certainly it is important to demonstrate that an ideal WHR (and the majority of evidence *so far* points to it being in the range of 0.7-0.8) is found to be universally attractive, and I would be amongst the first to disagree with experimental data being based solely on white, middle class, American college students. However, once one considers the confounding factors in terms of male ratings of female attractiveness it becomes extremely difficult to present stimuli that control for them all. Those studies that do at least attempt to mimic the ecological context in which these decisions take place (for example, by using manipulated colour photographs and brief –

  24. elem said,

    November 12, 2007 at 1:03 am

    wah – got cut off.

    …brief –

  25. elem said,

    November 12, 2007 at 1:04 am

    …brief – less than 1 sec – presentation) are perhasps more persuasive.

    I’m not trying to suggest that convincing cross cultural differences won’t be found, or that if they are found that this won’t be a serious problem for this particular theory but I don’t think the evidence is there yet. Until somebody gets a grant to fly a large sample of real women with varying WHRs, ethnicity, hair style, breast shape etc. between different cultures rather than using 2D representations of women, it’s going to be very difficult to have any confidence in the validity of the cross cultural results.

  26. elem said,

    November 12, 2007 at 1:41 am

    I guess in the end the WHR business can be viewed as a good example of the current state of ev psych…there is something good and (probably) meaningful underneath, but a lot of fluff to do with Playboy centrefolds etc. lies on top. I also think a lot of the research suffers from some typically wooly methodology that appears to plague experimental psychology.

    I can’t access the link referenced in the article, I guess it has gone. I do think that context is vital to know what that quote meant. Perhaps (speculating wildly) Cosmides and Tooby were referring to the “legend” as opposed to the “science” (of which I think there is some) of WHR?

    For example, Freese and Meelan conclude that “the unsupported repetition of an astonishingly narrow and invariant convergence to a 0.70 WHR in beauty icons only distracts attention from some of the field’s more measured discussions”. Couldn’t agree more.

  27. RS said,

    November 12, 2007 at 9:54 am

    Isn’t the normal range for waist to hip ratio something pretty similar to .7-.8 – with much over .8 implying central adiposity in women i.e. does the fact that men prefer women within the normal range of waist to hip ratio tell us anything interesting?

  28. ceec said,

    November 12, 2007 at 12:38 pm

    Speaking of which…
    news.bbc.co.uk/1/hi/health/7090300.stm

    Nigella:Oxford:Clever:QED

  29. BrickWall said,

    November 12, 2007 at 2:03 pm

    Isn’t the real answer here the same as for metaphysical questions? The only legitimate response to an evolutionary explaination for these observed (or not, whr!!) behaviours is “Who knows?”

  30. BarryNL said,

    November 12, 2007 at 3:38 pm

    Evolutionary psychology is great when you’re looking at phenomena like “blind-sight” and asking why the brain would have two separate visual pathways with only one available to the conscious mind.

    When looking at psychosocial issues though it’s generally little better than guesswork. Cultural pressures seem to totally dominate any evolutionary pressures. As Ben pointed out in the pink/blue article, 100 years ago it was pink for boys and blue for girls – how long would it take to imagine an evolutionary psychological reason for this?

    By the way, for an excellent spoof I recommend reading VS Ramachandran’s “Why Gentleman Prefer Blondes” paper which he sent as a joke to en EP journal and managed to get published:

    www.chass.utoronto.ca/~sousa/teach/rama.pdf

  31. RS said,

    November 12, 2007 at 6:13 pm

    “Evolutionary psychology is great when you’re looking at phenomena like “blind-sight” and asking why the brain would have two separate visual pathways with only one available to the conscious mind.”

    What does evolutionary psychology – as opposed to evolutionary thinking in cognitive neuroscience – have to tell us about blindsight and ‘parallel’ visual pathways?

  32. Will94 said,

    November 13, 2007 at 9:01 am

    BarryNL:

    Ramachandran’s paper was NOT published in an Evolutionary Psychology Journal. It was published in the journal “Medical Hypotheses” which is a journal for medicine and biomedical sciences.
    It was therefore unlikely to have been reviewed by anyone with any in-depth knowledge of evolution. Furthermore, although the article is wildly speculative, it does not contain the kinds of errors and downright contradictory nonsense that were contained in Alan Sokal’s hoax “post modernist” paper “Transgressing the Boundaries” published in Social Text.

    If you’re not familiar with this intriguing and sometimes hilarious episode read all about it here:

    physics.nyu.edu/faculty/sokal/

    Reference

    Ramachandran VS. (1997). Why do gentlemen prefer blondes? Medical Hypotheses. Jan, 48(1):19-20.

  33. Will94 said,

    November 13, 2007 at 9:27 am

    I know I’m at risk of talking to myself here, but I’ve just had a look at the Medical Hypotheses website (the one that published the Ramachandran paper in 1997), and it notes that:

    “Medical Hypotheses takes a deliberately different approach to peer review. Most contemporary practice tends to discriminate against radical ideas that conflict with current theory and practice. Medical Hypotheses will publish radical ideas, so long as they are coherent and clearly expressed. Furthermore, traditional peer review can oblige authors to distort their true views to satisfy referees, and so diminish authorial responsibility and accountability.”

    It is not clear whether “a radically different approach to peer review means that it uses a peer reviewing process or not but the telling statement is:

    “Medical Hypotheses will publish radical ideas, so long as they are coherent and clearly expressed.”

    Pretty easy to see, then, why Ramachandran chose this journal to publish his “hoax”.

  34. mikew said,

    November 13, 2007 at 3:43 pm

    A fallacy that I reckon many of the evolutionary “because …” statements make is that there is any “causal” link*.

    It might just be (for example) that menstrual hormones just affect muscles or joints in such a way that a particular walk is (dis)favoured.

    Yes, the bloke may find it more sexy, but that’s just luck – or maybe the evolutionary effect is on the bloke’s perception, rather than the woman’s walk.

    [Of course there is no real causal link anyhow – just selection]

  35. bob sterman said,

    November 24, 2007 at 1:32 am

    Mikew wrote…

    “It might just be (for example) that menstrual hormones just affect muscles or joints in such a way that a particular walk is (dis)favoured.”

    This would be a proximate explanation (how) – which is rather different from an explanation of ultimate causation (why).

    en.wikipedia.org/wiki/Tinbergen%27s_four_questions

    Proximate (how) and ultimate (why) causes are not alternatives – they are complementary.

  36. Robert Carnegie said,

    November 24, 2007 at 11:59 pm

    Yes – watching women walk is a pleasure as far as I’m concerned, but I can generally tell women from men any day of the month and it rarely crosses my mind to be curious about the women’s hormones. Cooking, ironing, endocrinology – best left to the ladies in my opinion 🙂

  37. A said,

    December 2, 2007 at 10:56 pm

    Robert Carnegie….idle, wanker?
    He reports, you decide.

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