Wednesday, May 18, 2011

I Have a Beef with Evolutionary Psychology

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There's this perception of science as an unbiased, value-neutral discipline, and it's kind of bullshit. You could be a scrupulous gatherer of data and an excellent statistician, but the scientific method is all about testing hypotheses, and those hypotheses can arise in very biased ways.

Some fields will be better than others; astronomy, for instance, has at best a rather tenuous relationship to our day-to-day lives. An individual astronomer could be biased towards the core accretion model of planet formation over the gravitational instability model, but, if so, that's probably due to her own publication history and will not translate to the whole astronomical community.

On the extreme other end of the spectrum we have the field of evolutionary psychology, which seeks to explain current human behaviors as hard-wired phenomena and is enmeshed in bias, I would argue inextricably. For instance, imagine what it would be like to study human attraction. It would be easy to come up with a hundred hypothesis motivated by sexism, classism, and racism. And you're going to get about one "positive result" with a p-value of 0.01 out of a hundred bullshit hypotheses. That's just statistics.

Furthermore, someone who is generating and testing sexist hypotheses is not going to be terribly motivated to consider alternate explanations for a phenomenon. And so we end up with Psychology Today posting articles about how black women are fundamentally less attractive, rather than about how our culture is reluctant to see beauty in black women. (Here's the Crunk Feminist Collective's take.)

Just to be clear, I definitely think that sociology and psychology are worth studying. But I also know firsthand how difficult it can be to extract statistically significant results from only a few hundred data points, and I know how tentative results can be misrepresented by the media. The result is that I have a high level of skepticism for evo-psych research in general, and this skepticism is increased by [1.] a hypothesis which sexists and racists would love to have proven correct, [2.] non-public data, and [3.] no reproduction of the results by another group.

A further example is an evo-psych study pointed out to me by a friend, about the supposed anti-depressant properties of semen, the controversy over which is unappealingly referred to as "Semengate". Now, again, I don't have access to the data, so I can't comment on their statistical analysis. But the very premise is problematic for at least four reasons I can think of:
  1. "Women be crazy." Seriously, that's how the study starts off: "Females are more prone to develop depressive disorders than males." Maybe because they live in a patriarchy? Maybe it's not semen-deficiency?
  2. It then proposes that they need a man to fix them. Specifically, through the regular application of semen to their vaginal walls.
  3. The whole thing is incredibly heteronormative.
  4. Finally, it's commonly assumed that men want to have unprotected sex. This study justifies that supposed want.
Furthermore, the study was based on a survey of a few hundred college women; not humanity's most representative group. It was conducted nine years ago and has not, to my knowledge, been reproduced since. This is exactly the kind of study that needs to be taken with a shipping container of salt.

The salt-taking stands even if you think that a study applies to you. I would love to believe, for instance, that my thousands of moles make me some kind of Bruce-Willis-in-Unbreakable type person. But, you know, I'm going to wait for the follow-up studies before I start taking that seriously.


  1. As a psychology major, I've had the unfortunate experience of having to cover some evo psych studies, and they all were nearly as bad as "Semengate." The majority focused on sex differences and all seemed to follow a pattern of:
    (1) Use scientifically questionable methods to find a sex (or race) difference.
    (2) Propose an evolutionary explanation (that is not falsifiable) for said difference, preferably including the word "natural" or "innate."
    (3) Avoid attempts to replicate results.

    The sad part is definitely when these studies manage to get published..

  2. Always good comments on dodgy statistical analysis, particularly of medical subjects in the media:

  3. "An individual astronomer could be biased towards the core accretion model of planet formation over the gravitational instability model, but, if so, that's probably due to her own publication history and will not translate to the whole astronomical community."

    For me, it's less there are not community biases in the "hard sciences" -- I think every field has *some* near-universal biases that are the result of accumulated views and the transmittal of those views (the history of math and physics is replete with those views). And it's not to say that these biases aren't problems -- they can contribute to stagnation and bad science. For me, the big issue is that the result of these biases have little impact (at least at present) on the world around me and people's lives. A bias towards the Higgs mechanism or a cosmological constant has little impact on public policy and people's lives. When crap Evo Psych studies come out, they're quickly picked up by the media and confirm people's biases (including those of policy makers). It really doesn't matter if Congress has lots of people who are biased towards inflationary models. It matters greatly if Congress has lots of people who think that Black people are more likely to be lazy, promiscuous, and unintelligent or that women are hormone-driven baby-machines. It doesn't matter if a judge and jury think that Many Worlds makes more sense than Copenhagen, while it matters greatly if they think that ovulating women who dress sexily cause men to become irrational and temporarily lose the ability to control their libidos.

    Sadly, evolutionary psychologists like Kanazawa -- apart from being piss-poor scientists with meager understanding of data analysis -- think that their work exists in an awesome objective vacuum where their work is unaffected by biases in the real world and their work has no effect on people in the real world.

    Kanazawa views himself as a fundamentalist scientist, and he doesn't realize how apt the term is. Kanazawa (and others) subscribe to a sort of empirical "sola scriptura" ( where data is given to them from on high in pure form and needs no contextualization or questioning of its validity.

  4. On the topic of Semengate:

    I feel like because people were so offended by this, as well as the serious repercussions for the scientists who performed the study, motivation for follow-up on the effects of male semen in the last 10 or so years may have been slowed. I have no evidence to prove that this statement is true, and I am not sure how I would go about that. But it is possible, and I am not sure how statistically possible it is. I do think that if you read the article you posted as "the supposed anti-depressant properties of semen" above, you will find that the author addressed some of the key points that were raised in opposition to Semengate. Also, you could argue based on the statements in your post about this that the opposition to semengate was in itself due to social narratives of a different kind.

    """ For what it's worth, I asked Gallup what he thought about Semengate. "I think it's a tragic overreaction," he says. "The point at which we begin to let a political agenda dictate what science is all about is the point when science ceases to be a viable enterprise." Considering how fascinating this research is -- and whether or not it offends our sensibilities -- I have to agree." """

    I feel like it is hard to deny that semen is really powerful. It is how you fertilize women. It is hard for me to reason that the cocktail of hormones released into the seminal fluid during ejaculation will not have some sort of effect on the female. The vaginal walls are densely packed with small veins very close to the surface that allow for quick absorption into the blood stream. I am not saying that this means semen effects the way women feel, but I think that there are sound arguments to support and instigate the research. Whether or not Gallup did a sound scientific study is another question.

    Hormones are powerful. An example that I find interesting in nature is this video of a how a parasitic wasp reproduces and how it can alter the host significantly... it becomes interesting after the larvae break through... so if you watch this, watch it to the end:

    This brings me to one last comment, that even if nature intends one thing or promotes something, I think it is important to understand what is happening, and as intellectuals we are able to overcome trends in nature when nature might not always be right, or is having trouble keeping up with the changing times :)

  5. "I have no evidence to prove that this statement is true"

    Indeed not. Since the furor known as Semengate took place ten years after the original study, I'm not sure what would have been inhibiting further study on the topic during that period.

    "you could argue based on the statements in your post about this that the opposition to semengate was in itself due to social narratives of a different kind."

    You would have to make that argument in more detail. After all, social narratives do not encompass all possible viewpoints. Our culture is heteronormative, not queer-normative. And though men's rights activists would have you believe otherwise, gender equality has not been achieved and feminist radicals are not dictating the course of society.

    "I feel like it is hard to deny that semen is really powerful."

    I won't argue with you about whether it's "powerful" or not, since I really don't know what you mean by that, but the (demonstrated) uses of semen are actually quite limited: the fertilization of an egg. Yes, that is a very important function if you would like to reproduce, but not everyone does. Calling semen "powerful" is a vague, highly unscientific, and patriarchically motivated justification for looking for additional purposes for that fluid. (Even the authors of the study attempt to do better than that.) You might as well call it "magical."