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We do a lot of arguing about evolutionary psychology in the comments here on DDP.

To get straight to the point: the really big problem with most evolutionary psychology is that to be ‘science,’ you have to be able to falsify it. You have to be able to test your hypotheses in way that will reveal if it isn’t true. And you have to actually ask that question. Without that, you’re just telling stories. You can tell your stories and I will tell my stories and we won’t agree because if you’re an “evolutionary psychologist,” you probably think sexism is “genetic,” and I’m a geneticist, and I don’t.

So I’m going to list a bunch of assumptions frequently made by “evolutionary psychology,” when it purports to explain the evolutionary basis of behaviors. Then I’m going to cite a specific example, and eviscerate it. Then, I’ll tell you what you’d have to change to make conclusions based in actual science.

[“our culture” means modern industrialized, Western culture throughout this article. the hyperlinked science terms have definitions if you mouse over them.]

  • Assumptions:
    • And my responses to them.
  • That there exists some sort of “ideal” environment in the long past that humans evolved to be ideally suited for.
    • Evolution is always a work in progress. There was never an ideal, perfect match between creature and environment, and there never will be.
    • Golden-age myths are never true. Not in literature, not in history, not in this. There is no golden age. There never was.
  • That our physical bodies have changed very little since then.
    • It is not valid to say we haven’t changed at all, or that your body somehow remembers its “natural” state from tens of thousands of years ago. It doesn’t.
    • It is valid to say that culture changes faster than our physical selves, and it is true that traits which may once have been adaptive (efficiency of fat storage, your appendix) may no longer be advantageous.
    • But our culture influences our physical evolution– height (our culture sexually prefers taller men), weight (the ideal changes from generation to generation but women require adequate body fat to bear children), average number of children (fewer and fewer recently), sperm count (dropping), older parents (increasing), increased survival of previously-poor-prognosis infants like extreme preemies (survival to reproductive age of people who previously would not). Our present population is not exempt from changing alleles and allele frequencies.
  • That behavior is physically present in our brains, and subject to evolutionary pressure.
    • This is certainly at least partially true. But remember that all phenotypes, from height to behavior, are the interaction of genes and the environment. For your brain, that includes not only what you put in your body but also all social feedback from personal conversations to media.
  • That our physical bodies are SOLELY the result of the accumulation of adaptive, that is, beneficial traits.
    • No. Evolution is not directed change. It is random change. Genes don’t predict environmental conditions and change on purpose. What changes is random; what gets retained may not be. Giraffes did not get long necks from stretching. They got long necks because giraffes who happened to have longer necks got more food. See the difference?
    • Genetic drift is responsible for far more population-level change than most people realize. Picture a bucket with 1000 marbles, half of which are red, half of which are blue. Draw any 800 at random, put them in a second bucket. Did you pick EXACTLY half red and half blue? Probably not. Add 200 more marbles to the second bucket, in the ratio of red:blue that matches the 800 you actually drew. Do that a bunch more times. Probably you will eventually end up with either all red or all blue marbles, utterly at random. Some evolutionary change is simply that randomness. And it gets accelerated if you only draw, say, 100 marbles each time. Fewer children in a given generation means you have a smaller chance of getting a random sample of the available genes. (If one, or a few, generations have exceptionally few offspring, it’s called a bottleneck, and it can change a population drastically in a short period of time.)
    • That a trait persists tells you nothing about whether or not it became more common under selective pressure.
  • That having the MOST offspring is the best reproductive strategy.
    • Hoo, boy is this one a doozy. This one is responsible for pretty much all of the “Men want to spread their seed!” myths. (dude, everybody wants to spread their ‘seed.’)
    • You actually need your offspring to reach reproductive age and themselves reproduce to effect your “fitness.”
    • Infanticide is a really common primate behavior. Including humans. Including super recently in recorded history, like, 14th to 19th century Europe, where “foundling houses” took abandoned infants and killed the very great majority of them through neglect. Presumably including since forever ago, since many primates with whom we share very distant common ancestors (and indeed, many other mammals to whom we are not very closely related at all) also practice this behavior in times of famine or stress or disease or changing social hierarchy or rape. More recently, women in developed countries have access, which I personally consider a moral good, to abortion. (except in some places not so much!)
    • Infants require their mother’s care. A man’s genes have a vested interest in the mother of his children not hating his guts.
  • That our social values have remained relatively constant throughout all of human history.
    • This one really boggles my mind, but it is what you are assuming when you try and use present-tense cultural conditions to try and explain what you want to call evolved behavior.
  • That our post-agricultural revolution social values and gender power balance is constant throughout all of human history.
    • Very simply stated: this is not true.
    • Social power dynamics are very different in societies that have the means of accumulating material wealth. That is really only possible for post-agricultural societies. aka not hunter-gatherers. aka not most of human history.
    • That a man need to know, FOR SURE, who his children are, for the purpose of giving his property to them and only them, is a pretty recent convention relative to the scope of human history. There isn’t any reason to assume people gave a shit about passing on property to only their children when there wasn’t much in the way of property to be passing around.
    • That women are socially subservient to man and do nothing but tend children while men support a nuclear family is also a super recent convention. And, specifically, women in hunter-gatherer societies contribute half or more of the calories to the community diet. It’s not all man-meat, all the time. Here’s a bit of data if you want to look at it. Figure “S2.” That women would have starved with out men to provide for them is a lie.)
    • Women had fewer children pre-agriculture, so there was less looking-after-children to do, which affects how women spend their time.
  • That human mate selection can be reduced to males competing for the attention of females.
    • At any “then” you care to consider, including now, women make choices. They are not passive prizes. (Sometimes they actively choose to be prizes, but that’s still a choice.) Even for much less socially complex animals than humans, the competing males and passive females model becomes obviously too simplistic real fast.
    • Even super “monogamous” animals, aren’t. There’s no reason to assume humans are any better at it in practice. (There are some physical clues that counter that assumption anyway, like testicle size, which on humans indicates sperm competition aka not monogamy.) Which means the effect of any strategy that relies on rigorously policing human females is likely to be severely diluted. In fact, [geneticist hat] if you’re doing a scientific study with humans that involves any familial analysis, your ethical protocol won’t be approved unless you have specific contingencies for excluding subjects whose father of record is not actually the father. 10-15%.

It’s true that our physical bodies haven’t changed dramatically since we became Homo sapiens. It is, in face, tautologically true– if you go too far back you get to “not Homo sapiens.” And it’s true that at least some behavior has a genetic basis.

Example (reported widely in popular media, including Salon):

If you tell me that men read men’s emotions better than they read women’s emotions, and it’s associated with specific activity in the area of the brain associated with empathy, that’s an observation. That is actually really interesting.

But if you then tell me that it’s because:

From an evolutionary point of view, accurate interpretations of other men’s rather than women’s thoughts and intentions, especially threatening cues… may have been a factor contributing to survival in ancient times. As men were more involved in hunting and territory fights, it would have been important for them to be able to predict and foresee the intentions and actions of their male rivals.

then you are full of shit. You have no idea. Men’s ability to empathize with other men may indeed have contributed to survival. Men’s ability to empathize with women may also have, because humans are incredibly social animals and have been for all of their existence. So I’m thinking “your story” has some flaws.

Here’s my story– the human brain is incredibly plastic, and strengthens connections we use and need and prunes the ones we don’t. In our current culture, not some speculative former one, men are taught that men and not women keep social power. I can’t speak with absolute confidence about then. But men now have a far greater vested interest in being able to foresee the intentions of other men than they do of women. So men pay more attention to other men, and learn to read them better. The brain-activity data in the study suggest that men fail to read women’s emotions because they aren’t able to empathize with them. (“mentalizing.”) Because they are congenitally unable to do so? I very much doubt that. Because they aren’t taught that they need to? That would be my guess.

My story is just as plausible as “yours,” though neither of those are science without being tested. But the neat bit is that my story is testable. I can think of a couple of ways.

You could do the same study, ideally with men raised in male-dominated cultures like ours but then compared with men raised in female-dominated cultures, except there are none. What you could realistically do, is test men raised in both more and less egalitarian cultures than the United States, and see if the difference correlates with cultural measures of social power difference and misogyny. Are American men better at reading women’s emotions than Saudi men? Are they worse than Swedish men? You could give the test to pre-pubescent males raised by single mothers (or two mothers) vs a mother and a father vs single fathers (or two fathers).

Do any of those cultural factors influence the data? If so, that supports a current cultural explanation. If not, it doesn’t say anything one way or the other about the specific proposed explanation of men and threats and whatnot. But it might support a more biologically-determined explanation.

But way, way too often, “evolutionary psychology” is simply used to throw the weight of ‘science’ behind the status quo. Men should have no penalty for sexual infidelity. Women should have ALL THE PENALTIES. Men can’t talk to women! Christ, women talk SO MUCH! They must have gossiped while picking berries or some shit! Men treat women as objects! But only because the object-processing part of their brain lights up when they see hot women! Which is definitely not because they’ve been taught women are objects!

How we make it science– observe things. Identify assumptions. Question assumptions. Propose plausible explanation. (Also think of other possible explanations.) Test favorite proposed explanation.

Most “evolutionary psychology” that you will read about in popular news doesn’t even bother to think about any alternate explanations than sexism and the status quo, let alone propose any way of testing their speculation. They don’t even bother to address many of their very problematic assumptions (listed above), many of which are, frankly, not actually valid. But it’s passed off to the public as “science,” either by the researchers themselves or writers at news outlets.

Far too often, it isn’t science at all.


Many of the words in this article link to further reading, especially on the science concepts. Enjoy!

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