Posts Tagged ‘evolutionary psychology’

Are you a fan of criticizing evolutionary psychology? Grab some popcorn, folks, because there has been some criticizing and counter-criticizing going on that you may find entertaining! In most cases, it’s actually serious, well-reasoned debate, too (as long, I assume, as you don’t read the comments). Things began with Rebecca Watson‘s talk about pop evo psych at a skeptic conference, which was…I won’t say “debunked”, but countered, by evolutionary psychologist Edward Clint. This has sparked some dialogue, primarily on Freethought Blogs, about evolutionary psychology as a whole field and about the media coverage of the science (or, often, “science”) of gender differences. I present the (interesting parts of the) conversation so far in chronological order (perhaps I’m missing some contributions from blogs I don’t regularly read, so additions in the comments are welcome; also please note that I’m interested in collecting links that discuss the science or lack thereof involved, NOT those discussing What Rebecca Watson Really Meant):

Edward Clint’s response to Watson’s talk (the latter is embedded here and at the first Almost Diamonds link below)

Justin Griffith’s take on the above

Stephanie Zvan’s rebuttal of Edward Clint’s post

Tangential to the debate per se, Zvan also documents the gleeful response from the section of the internet that reflexively detests Watson

Zvan’s counterarguments, continued

PZ Myers begins a series critiquing evo psych

Clint’s response to criticism (this, and some other posts linked within, is more about tone and whether people are misinterpreting what other people said/wrote, which I consider not popcorn-worthy because I want to read about science)

Jerry Coyne discusses the field

Part II of Myers’s critique (and apparently more parts are planned)


Myers, part III

Greg Laden’s take

Shall I write up my own contribution here? Perhaps if I run out of popcorn.


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I’m confused. Am I supposed to wear red to attract a mate, or not?

ResearchBlogging.orgThese seemingly contraditory findings (which, as I’ll explain in a moment, aren’t actually contradictory) were amusingly published in the same journal within less than two weeks of each other, so I can’t resist a discussion.

It’s an old canard of pop evolutionary psychology that the colour red denotes sex. It had been hypothesized that red ornamentation—especially lipstick—mimics the colour of receptive female genitalia, and therefore advertised (perhaps falsely) fertility or sexual receptivity. A study which I described several weeks ago laid this particular hypothesis to rest by showing that straight men were less sexually interested in pictures of redder female genitals. But still, the colour red has strong cultural connotations, perhaps with evolutionary significance. The newer study was intended to show that red denotes (female) sexual availability—particularly for casual sex.

This study had three parts. First, the researchers recruited women and asked them to pretend they were creating an online dating profile. Half of these women were asked specifically to imagine that they were creating this profile to find casual sex partners. They were asked questions about what their profile picture would look like, including whether they would wear jewelry, and what colour they would wear. Interestingly, they were given only four options: green, blue, black, and red. Women in the “casual sex” group were indeed more likely to say they’d wear red, but by only a small margin (it was just barely statistically significant, at p=.047).

The next part of the study looked at whether this stated preference existed on real online dating sites. The researchers selected profiles of 500 women who were looking for casual sex and 500 who weren’t (must resist urge to make snide remarks about this methodology!). They had three people classify the predominant clothing colour in these profile pictures (again, only red, black, blue, and green were considered). And, indeed, women who were interested in casual sex were more likely to wear red prominently than those who weren’t*.

The third and final part of this study was similar to the second, except that it compared women on websites specifically dedicated to casual relationships to women on sites that emphasized more long-term relationships. A similar result was found: red was more common on the casual sex-focused website.

Now, what can and can’t we conclude from these results, assuming they’re sound? We can say for sure that women (more specifically, women who fit the online dating demographic) who are looking for casual sexual relationships tend to display red clothing more often in the context of looking for those relationships. We cannot say whether this tendency is learned or instinctive, or whether it has an evolutionary “purpose”, or even whether it has anything to do with fertility (=fitness). The authors of this study do a great job of pointing out these limitations. For example, they note that their findings may not hold for face-to-face interactions or for all personalities.

I want to discuss why these results say little about evolution, though, because this is the sort of study that tends to be spun into an evolutionary psych fairy tale. First, it does not distinguish learned from genetically entrained behaviour (and, of course, there may be a little bit of both genes and memes at play). But if this red=casual sex link has a weak genetic basis, it’s probably not something that arose in our species as a result of natural selection in the traditional sense. Second, there’s an underlying assumption that red=casual sex=increased fitness (i.e. more babies). I have a feeling that the average woman these days is not pursuing casual sex in order to get pregnant. Perhaps this was the case in our evolutionary past, but it’s a pretty big assumption.**

Nevertheless, this study is not bad in terms of making wild claims about evolution. I do have some problems with its methods, though. Only four colour options? (None of which include, say, orange or pink—something closer to red.) And no mention of whether shades of pink, orange, or purple could be classified as red. On top of that, having people score what they thought was the “most prominent” colour in the profile pictures seems like not the best method, even though it was repeatable between scorers. (I’m thinking you could come up with a Photoshop manipulation to determine redness of a selected area of clothing. I think it’s been done with stickleback! (That is, with their red throats, not their clothing.))

What you can take away from this paper is that red is associated in women’s minds with sexuality in certain contexts. This is probably not surprising to anyone, but having data to back up the conventional wisdom is always good. However, it’s a huge stretch to ascribe evolutionary significance to this observation. Whether it’s as far a stretch to use it to choose your lipstick colour, though, is entirely up to you.

This study has also been covered eloquently at Scicurious. (Special bonus points to this set of comments.)

*For both of the online dating site studies, most photos had people wearing black, which is interesting if red is really that important a signal. Also, why were so few people wearing green? It’s clearly the best colour. (But not a real green dress, that’s cruel.)

**Also, and this is a question I could probably answer easily with a bit of Google Scholar-ing but I’m too lazy, what about red-green colour blindness, which occurs in 10% of men?

Elliot, A., & Pazda, A. (2012). Dressed for Sex: Red as a Female Sexual Signal in Humans PLoS ONE, 7 (4) DOI: 10.1371/journal.pone.0034607

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ResearchBlogging.orgThere’s a tired pop evolutionary psych idea that gets repeated by scientist and nonscientists alike—I think I heard it most recently in the movie “Hanna”—that red lipstick is meant to be a symbol of engorged female genitalia, and thus that lipstick is meant to signal sexual receptivity and possibly fertility. This idea apparently dates back to a chapter called “Sexual selection and human ornamentation” by one B. S. Low in a book called Evolutionary Biology and Human Social Behaviour. It’s called the “sexually salient” hypothesis—the idea that the colour red is attractive because of its resemblance to naughty bits. Supporting evidence (“evidence”?) for this idea included various studies indicating effects of the colour red on people’s perceived attractiveness, performance in sports, and perceived social dominance, as well as the fact that numerous primate species, especially baboons, have exaggerated, red female genitals and a corresponding male preference for red. Not surprisingly, the idea wasn’t properly tested but was picked up and repeated. Let me toss out a few objections to it before we even get to scientific hypothesis-testing. First, those primates with red genital displays have lots of body hair but hairless genitals and are quadrupedal. Humans are kind of the inverse, having pubic hair but little body hair, plus we walk on two legs, so chances are that female genitalia weren’t constantly on display in our australopithecine ancestors. Furthermore, redder lips could simply be a signal of better overall health or fertility, regardless of whether lip colour correlated with aroused genital colour.

If human females use red ornamentation to attract males by coopting a male preference for redder “sexual skin” as an indicator of fertility, we’d expect the following: male preference for redder female genital skin, male preference for redder lips (this relationship seems to be somewhat validated), and a correlation between female genital colour and health and/or fertility. The latter two predications would be tricky to measure properly—are we talking about a between-person correlation between a woman’s lip colour, labia colour, and health/fertility, or one that occurs within an individual woman over the course of her menstrual cycle? On top of that, we’d have to be careful to rule out a preference for red lips because they indicate health/fertility, as opposed to a preference for red lips because they look like more fertile genitalia. It would be easier to test—and easier to disprove—the first hypothesis, that men prefer redder female genitalia.

A new PLoS ONE study has done just that, using pictures of female genitalia digitally manipulated to be different shades of pink/red within the normal human range. They asked forty straight men to rate these pictures on a 1 to 100 scale of attractiveness. Interestingly, they rated the darkest red images as least attractive. Nor was there a correlation between attractiveness and the shade of pink. Hypothesis effectively rejected. Well, let me throw in some caveats about sample size (40 isn’t that many participants) and demographics (while the authors didn’t report anything about the age or race of their test subjects, perhaps their sample was too uniform to show anything*). Regardless, the preference for pinker genitals stands in sharp contrast to data on preference for red lipstick, clothes, and other ornamentation, making the “sexually salient” hypothesis highly unlikely.

This study does something I’m fully in favour of—testing a widely-repeated but unsupported idea—and disproves the hypothesis pretty soundly. It doesn’t, however, manage to break away from the assumption that a male mate preference must be universal and adaptive. It is entirely possible that strong evolutionary pressure shaped human male preference for a certain genital colour, and the authors list some quite plausible such pressures: menstrual blood (which indicates that a woman is not ovulating at that time) and diseases like yeast infections and trichomoniasis (which can cause reddening of the labia, and would put a mate at risk of infection). They don’t raise the point that a lower preference for red could also be cultural, though they do cite a study that found no change in the redness of Playboy centrefolds’ labia since the late fifties, suggesting at least that no recent cultural trend explains the preference for pink. But this preference doesn’t have to be adaptive at all—especially if vulva colour was never an important part of mate choice in our recent ancestors. Indeed, preference for red ornaments needn’t be adaptive or even genetically based either—just look through the archives of Sociological Images for examples of how the meaning attached to different colours changes over time and between cultures. Take-home message: test your hypotheses, but make sure you don’t limit your alternative hypotheses as well.

*But let me just say that, since many pop evo psych ideas come from observations of Western cultural expectations, if we can disprove it for a sample that fits those expectations, that’s a pretty strong sign.

Johns, S., Hargrave, L., & Newton-Fisher, N. (2012). Red Is Not a Proxy Signal for Female Genitalia in Humans PLoS ONE, 7 (4) DOI: 10.1371/journal.pone.0034669

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Well look who’s avoiding her thesis work by writing two posts in one day! (Even if they are both basically link dumps.) Dear readers, please direct your attention to this post by Greg Laden of ScienceBlogs. It is basically the final word, by an anthropologist, on how evolutionary psychology that aims to study gender differences has gone awry.

I’ll just add one comment to it: the sex differences that are caused by developmental modifications, like the effect of testosterone on neurons that “probably accounts for the fact that there are almost no male simultaneous translators”, don’t cause a strict binary. There are almost but not entirely no male simultaneous translators; there are many females who are not simultaneous translators. There’s a statistical skew with respect to sex (that is, among cis-gendered individuals, which is almost exclusively what research of this ilk deals with), but not every member of each sex is typical of the overall pattern. And so, if you’re using a pattern like this as a shortcut to understand the opposite sex (or people of another ethnicity, because the same argument applies), you are stereotyping, or in other words, being an asshole.

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This idea has been drifting around in my head for a while now. I recently went to a talk that helped me solidify what I wanted to say about it. Here goes.

Everyone loves to hate evolutionary psychology, particularly the sometimes-garbled versions that make the headlines*. And it’s not just because these headlines sometimes (often) emphasize gender or (less often) racial stereotypes that reasonable people find repellent. There is often genuinely bad science involved, and I think it’s the responsibility of the scientific community to call this out. Now, that’s not the point of this post.

The point is that bad science is often better for advancing a field than good science. (more…)

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