Awesome takedown of several evolutionary psychology claims

[marydell]

This article gives an overview of a lot of the popular evolutionary psychology claims of the last 20 years--gender-based differences in jealousy, men's universal preference for hourglass female figures, rape as an adaptation that improves men's evolutionary fitness (ie ability to successfully propogate their genes), killing of stepchildren as a similar adaptation--and the actual scientific evidence that shows they're basically  horseshit. AWESOME.  Excerpt concerning rape: 

Hill had something almost as good as a time machine. He had the Ache, who live much as humans did 100,000 years ago. He and two colleagues therefore calculated how rape would affect the evolutionary prospects of a 25-year-old Ache. (They didn't observe any rapes, but did a what-if calculation based on measurements of, for instance, the odds that a woman is able to conceive on any given day.) The scientists were generous to the rape-as-adaptation claim, assuming that rapists target only women of reproductive age, for instance, even though in reality girls younger than 10 and women over 60 are often victims. Then they calculated rape's fitness costs and benefits. Rape costs a man fitness points if the victim's husband or other relatives kill him, for instance. He loses fitness points, too, if the mother refuses to raise a child of rape, and if being a known rapist (in a small hunter-gatherer tribe, rape and rapists are public knowledge) makes others less likely to help him find food. Rape increases a man's evolutionary fitness based on the chance that a rape victim is fertile (15 percent), that she will conceive (a 7 percent chance), that she will not miscarry (90 percent) and that she will not let the baby die even though it is the child of rape (90 percent). Hill then ran the numbers on the reproductive costs and benefits of rape. It wasn't even close: the cost exceeds the benefit by a factor of 10. "That makes the likelihood that rape is an evolved adaptation extremely low," says Hill. "It just wouldn't have made sense for men in the Pleistocene to use rape as a reproductive strategy, so the argument that it's preprogrammed into us doesn't hold up."

Concerning sexual jealousy:
 

In questionnaires, more men than women say they'd be upset more by sexual infidelity than emotional infidelity, by a margin of more than 2-to-1, David Buss of the University of Texas found in an early study of American college students. But men are evenly split on which kind of infidelity upsets them more: half find it more upsetting to think of their mate falling in love with someone else; half find it more upsetting to think of her sleeping with someone else. Not very strong evidence for the claim that men, as a species, care more about sexual infidelity. And in some countries, notably Germany and the Netherlands, the percentage of men who say they find sexual infidelity more upsetting than the emotional kind is only 28 percent and 23 percent. Which suggests that, once again, it depends: in cultures with a relaxed view of female sexuality, men do not get all that upset if a woman has a brief, meaningless fling. It does not portend that she will leave him. It is much more likely that both men and women are wired to detect behavior that threatens their bond, but what that behavior is depends on culture. In a society where an illicit affair portends the end of a relationship, men should indeed be wired to care about that. In a society where that's no big deal, they shouldn't—and, it seems, don't.

And concerning body type preferences:
 

 

Later studies, which got almost no attention, indeed found that in isolated populations in Peru and Tanzania, men consider hourglass women sickly looking. They prefer 0.9s—heavier women. And last December, anthropologist Elizabeth Cashdan of the University of Utah reported in the journal Current Anthropology that men now prefer this non-hourglass shape in countries where women tend to be economically independent (Britain and Denmark) and in some non-Western societies where women bear the responsibility for finding food.

Comments

[ashnistrike.livejournal.com]

I feel the need to point out (because I'm pedantic and it's near my field) that while some of evolutionary psychology is the oversimplified, sexist idiocy that this article does such a good job of taking down, much of it is more nuanced and sensible. Buss and colleagues get pretty far on overdramatic claims, because the tenure and promotion process, in good evolutionary fashion, often selects for people who make dramatic claims comprehensible outside of their field. It's the same logic as my first-year student who claimed that there's a gene for going to church every Sunday.

On the other hand, plenty of ev psych researchers realize that evolution selects for genes, not behaviors. So is there a gene for rape? Probably not. Is there a gene for testosterone levels, that leads to adaptive fertility at middling levels, and nonadaptive culturally shaped aggression at high levels? More likely. Gene A provides protection from malaria with one copy, causes sickle-cell anemia with two. Gene B leads to creativity and flexibility with a middling number of copies, a predisposition to schizophrenia with a high number of copies.

Please excuse the lecture; I go through the struggle over this distinction every semester.

[marydell.livejournal.com]

See, this is why scientists are awesome - I knew you would have enlightening things to say about this. Lectures from you are entirely welcome! I'm curious to know what you think about the competing versions of "how the brain works" that are sort of mentioned in the article.

I don't think the whole field is hogwash, just that the popular bits of it seem to be, because its ideological facets seem to get all the play. A lot of the arguments that get seen in public look like fancy retconning jobs in which the flaws of our society--particularly the sexist & racist ones--are proven to be inevitable based on evolution. Anthropology has been guilty of a lot of this as well, as have some other Evolutionary sciences. Old-school anthro, in particular, seems to have been looking for the one truly natural human culture, in order to enshrine it.

[ashnistrike.livejournal.com]

They are right that the "behavioral modules" model of the brain is vastly oversimplified. The brain does have modules for many things, but usually big things like "language production" or outgrowths of semantic organization like "names of celebrities." The former are probably coded for genetically--Broca's Area is in basically the same place on everybody--while the latter are obviously not, at least in the specifics. But something like mating behavior draws on many different parts of the brain--planning, emotion, person modelling, et cetera, which are not even in the same lobe let alone the same specific physical area.

What's "natural" human behavior? Language use, heuristic-based problem solving, a variable balance between aggression and altruism, complex social organization, and the ability to adapt flexibly to the environment. We're the only species that has viable populations in both equatorial Africa and Antarctica; that doesn't suggest behavioral rigidity to anyone with sense.

[ashnistrike.livejournal.com]

And yes, popular science is often based more on drama than evidence. I'm glad you linked to this article, by the way--I hadn't encountered the more recent evidence against Buss, and will have to look it up before next semester's Learning Theory class, which gets Buss as an assigned reading. (And then I spend a couple of hours trying to Socratic method the students into noticing the flaws.)

[fledgist.livejournal.com]

There's a gene for going to church every Sunday? Funny. I have the gene for sleeping in on Sundays. I also have the gene for waking up earlier than I need to when there's an urgent need to wake up early.

[ashnistrike.livejournal.com]

I definitely have the sleeping-in gene. For waking up early, I need an alarm clock--fortunately the clock has the gene for making loud noises at a user-specified time.

[fledgist.livejournal.com]

I, also, have to make use of that genetically-enhanced alarm clock to make sure that I get up at a predetermined hour on most days.

[cathshaffer.livejournal.com]

The selfish gene is only one perspective on evolution, and one losing ground lately. The pendulum seems to be shifting back to the organism as the unit of evolution.

With regards to rape, the analysis above contains a lot of assumptions. For example, it assumes that the rapist is not the husband or some other male with a socially sanctioned right to sexual access to a particular female. It assumes a society which recognizes and values female consent. There are many examples of aboriginal human groups which have systematized rape, and where the men to do not suffer any loss of "fitness points" at all for it. It also assumes a society that understands the "facts of life" and that babies result from sex. Almost all human cultures studied in the 19th and 20th centuries have this knowledge, but some do not. Going back in human history, particularly the very deep evolutionary history in which these behaviors would have formed and been preserved, it is less likely that this connection would have made. The human social behavior described above is 40,000 years old at the maximum, but evolution works on a scale of a million years or more. We could be saddled with behavior that was advantageous for australopithecus or some other stage of human evolution. There is plenty of "nonconsensual" breeding behavior among animals, so it is not really so much an ev-psych issue as some of the others.

As well, they have not made an adjustment for induced ovulation due to sexual trauma, which is a real phenomenon, although I don't know what the frequency is.

[ashnistrike.livejournal.com]

Selfish gene or no selfish gene--I've always found the phrase a bit overdramatic and reminiscent of homunculi--genes are what is selected for by evolution. And genes have more than one influence on behavior. Not every genetically modified behavior is the one that made that particular gene adaptive--all that can be said is that it's not so maladaptive that no one with it breeds. There are enough genes that influence aggression, and enough culturally mediated variation in how that aggression plays out, that genetic coding for particular forms of aggression seems to overreach the data.

[ashnistrike.livejournal.com]

I should add that I do agree that not all societies select against rapists (more's the pity), especially non-stranger rapists. I'm just not convinced that there's a specific gene for it.

[seawasp]

None of the implied crap was in ANY of the evolutionary psych I was taught in college, I have to say.

[sanguinity]

:: Hill had something almost as good as a time machine. He had the Ache, who live much as humans did 100,000 years ago. ::

I'm having a very difficult time getting past that latter sentence. We don't even know if humans were already starting to develop modern language 100,000 years ago, or if that was another 50,000 years down the road.

Is it seriously being suggested that the Aché are not modern humans?

[fledgist.livejournal.com]

That's a very good point. The "much as" is being used to cover a multitude of sins.

[marydell.livejournal.com]

Yeah, that is some pretty good weasel speak. But anatomically modern humans have been around for about 200k years (which, yes, doesn't address social structures like language)...I suspect that what's meant is simply that the Ache are a hunter-gatherer society. (http://en.wikipedia.org/wiki/Ach%C3%A9)

Arguably, all humans live "much as" humans did 100,000 years ago, since it "much as" is meaningless. We eat food, we form social groups, we bear live young...

[sanguinity]

I was referring to behaviorally modern humans, not anatomically modern; it is behavior that the article is focusing on.

And I wouldn't say "simply" -- there's an additional implication being made that modern hunter-gatherer societies are closer to paleohuman societies than they are to other modern societies. It's a common implication. Which, again, if we're talking about paleohuman societies that could well have been pre-language, societies which had not yet become behaviorally modern, is fairly insulting.

[browngirl.livejournal.com]

This was one of my points of disagreement with the article, too; you put it better than I would have.

That said, overall, I think this article will be useful next time I have to deal with a "men are just programmed to rape so it's not really wrong" - spouting moron.

[sanguinity]

I usually argue the position that "is" doesn't make any representation about "ought," which at least doesn't leave me backed me into a corner if the science changes. But by all means, use whatever tack you can argue best.

[marydell.livejournal.com]

I think a 2x4 to the head is a good counterpoint to that particular rape argument, but the law is unfortunately not with me on that. I have been known to say "and I am programmed to come over to your house and steal your TV, so you won't mind when I do that, right?"

But I do think it's useful to have stats that show that "is" and "ought" may actually be on the same side in many of these scenarios, when many people want to argue that biology is what makes us immoral.

[sanguinity]

Also, a 2x4 to the head is one of those is/ought solutions. ;-)

I like the line about the TV. I find those kinds of counter-examples to be pretty effective at disrupting someone's thought pattern. (Whether it sticks is another matter; but hey, disruption is a great first step.)

[cathshaffer.livejournal.com]

Yeah, that is not okay. The fact that something exists in nature does not make it morally right. This type of moron should be forced to dig a hole every time he needs to take a dump.

[marydell.livejournal.com]

Agree 100% about the problematic implication that modern hunter-gatherer societies are not really modern humans, but I didn't pick up on that until you pointed it out--thank you. I've gotta think about that because that notion of the "lost paleolithic tribe" is so ingrained in Anthropology. And fits so nicely with imperialistic agendas.

I'm not sure if I agree that the arguments of evolutionary psychology are behavioral at their core--they seem to be all about tying behavior to anatomy, or a theory of brain anatomy anyway. Genetic predisposition to certain behaviors coupled with poor theory about reproductive success. But I think I'm making a mistake in assuming that we're genetically very similar to the original homo sapiens sapiens. I have these large sweeping evolutionary categories in my head, with the most recent one including 200k years of humans - but of course evolution never stops.

[sanguinity]

Quite. One of the surefire things to get me to yell at the computer screen is a pop-sci article that implies that human evolution is "finished" or has "stopped." (But if we were to start talking about popsci representations of evolution that make me yell, we could be talking for a while.)

According to Brittanica, the Aché are anything but a "lost paleolithic tribe": pre-Conquest, they were agricultural. If their subsistence methods are "extremely simple" (as Wikipedia suggests), that's more likely to be because they've been refining them for only a few hundred years than because they spontaneously re-created a middle paleolithic society.

[cathshaffer.livejournal.com]

Modern homo sapiens begins around 40,000 years ago. That is when grave goods and evidence of religion begin to appear in burials, and it is also when many anthropologists believe that language emerged. We cannot but be pretty much genetically identical--40,000 years is not much. Modern homo is also the product of a pretty severe bottleneck (I forget the dates) so that we are even more identical to each other than most other species on the planet. So little is known about the genetic basis of behavior, however, that it is possible that tiny changes make a big difference. Possibly even epigenetic changes that do not appear in the DNA code itself.

Such a fascinating topic, and interesting comment threads.

[ashnistrike.livejournal.com]

I'm suspecting poor translation from original research to lay article, here. If the researchers think they know the size and behavioral patterns of early hunter gatherer societies, they don't need the Ache to model those things. On the other hand, modern hunter gatherers would tell them something about fertility and healthy live birth odds with that particular lifestyle and calorie intake, and I would guess that's why they needed those observations.

[cathshaffer.livejournal.com]

Such a good point. Modern hunter gatherer societies can tell us a lot about human culture, but they are not a proxy for a 100,000 year old culture. Modern HG cultures are just as old as western civilization, and in their complexity may not at all resemble a primal human culture--if there is such a thing.

[fledgist.livejournal.com]

About 140-150K years as I understand it. Last I read language, as we use it, hasn't been around nearly as long. Your last point's quite true!