Your title “Problems in Evolutionary Psychology” is a bit ambiguous. Does it mean problems with the field of evolutionary psychology, or does it mean problems in the field of evolutionary psychology that evolutionary psychologists themselves are grappling with?
This post introduces some of the issues in studying evolutionary psychology, but off the top of my head, my reading on the subject suggests that evolutionary psychologists are aware of most of them and have taken them into account. So the second meaning would make more sense to me.
Either way, I think it would be useful to discuss what evolutionary psychologists think are the inherent difficulties in their fields (and how they propose to deal with them), and how they answer broad criticisms directed at the field. Evolutionary psychologists have been criticized a lot, and have spilled gallons of ink explaining their views in journals. I will try to find something that’s a good introduction and that isn’t behind a paywall.
In particular, evolutionary theories about sex differences seem to get mentioned and appealed to as if they had an iron-cast certainty.
Could you give an example of someone making this error?
Women have less strength than men and are the ones who bear children, which could easily have affected their social position even without drastic psychological differences.
Ah, but why do women have less strength, and men have more? See the excerpts from David Geary’s Male, Femalehere arguing that greater male strength is related to sexual selection. (The mere fact that females have the babies isn’t enough, because many monogamous primates exhibit minimal dimorphism.)
We know that there were different selection pressures on men and women. It doesn’t make sense to believe that these selection pressures were strong enough to change body morphology, but somehow had no effect on psychology and behavior. That would be “neck-down Darwinism.”
Of course, it is hard to tell whether a present-day sex difference is an adaptation, or not. A lot of arguments that X is or isn’t an adaptation seem too black-and-white; instead, we should be talking about probability that a trait is an adaptation. In many cases, evolutionary psychology has made predictions based on hypothesized adaptations, which have turned out to be true, especially in the area of mating preferences. I’ll try to get some citations for you. These findings should lead us to increase our probability estimates that such behaviors are related to adaptations.
Occasionally, the studies purporting to show cross-cultural sex differences actually show that the differences are smaller in the more egalitarian countries.
I think your post could use a couple citations for this claim. Off the top of my head, this claim may be true for some traits, but I’ve also seen evidence that it is false for others.
Even behaviors that were very widespread may or may not apply to any particular individual. Lists of ”human universals” will tell us that members in every tribe found so far will interpret facial expressions, love their children, tell stories, feel pain, experience emotions, and so on. But there are also individuals who do not know how to read facial expressions, do not care for their children, are not interested in stories, do not experience pain or emotions, and so on. Sexuality is one of the drives that would have had the strongest selection pressures operating on it, but we regardless have people who have no interest in sex, are mainly interested in sex with things that you cannot reproduce with (same-sex partners, children, cars...), or prefer to just masturbate.
It’s true that there is variation. Though variation needs to be investigated further before it tells us much about the plausibility of evolutionary hypotheses. Evolutionary accounts have many reasons to predict variation, e.g. frequency-dependent selection.
Furthermore, some of the examples you describe may be related to biological but non-evolutionary factors. There is evidence that prenatal hormones influence human psychology. Many factors can influence the prenatal environment, such as maternal stress.
So, just because we see a certain sort of variation, it doesn’t necessarily strike down the hypothesis of universal, or quasi-universal, evolved human predispositions. Prenatal factors can counter-act or modify evolved predispositions. Of course, we shouldn’t hand-wave any variation by saying “that’s just prenatal noise;” we need actual evidence suggesting that variation in a trait is prenatal. And for some items on your list, that evidence exists, so that variation doesn’t cast much doubt on the plausibility of a high evolved similarity in human psychology.
That sort of information can only be found by ordinary empirical research,
Certainly. But don’t evolutionary psychologists know this? And I’m talking about what evolutionary psychologists write in peer-reviewed publications, not speculation in popular books.
and ordinary empirical research doesn’t need evolutionary psychology for anything else than suggesting interesting hypotheses
No, but your language here seems a bit strange, because a method for generating interesting hypothesis is a really important part of science. Having great procedures for testing ideas is no use if you have no ideas.
To me, that quote sounds something like saying “boats don’t need navigators for anything else than finding where they are going at sea.”
Could you give an example of someone making this error?
Robin Hanson does this on a pretty regular basis. Most of his reasoning about gender is based on a male provider, female nurturer model. He is very much not alone.
I should have made it more clear in the post that the primary target of the post was not professional, academic evolutionary psychology. Rather, I was primarily cautioning amateurs (such as LW regulars) about some of the caveats involved in evpsych and noting the rigor required for good theories. While the post does also serve as a warning to be cautious about sloppy research (or sloppy science journalism) that doesn’t seem to be taking these issues into account, I don’t question the claim that the people doing serious evpsych are aware of all the issues I mentioned, and are probably taking them into account.
Could you give an example of someone making this error?
My wording was probably a bit too strong. Anyway, I’ll try to look up some examples once I wake up.
Ah, but why do women have less strength, and men have more? See the excerpts from David Geary’s Male, Female here arguing that greater male strength is related to sexual selection. (The mere fact that females have the babies isn’t enough, because many monogamous primates exhibit minimal dimorphism.)
We know that there were different selection pressures on men and women. It doesn’t make sense to believe that these selection pressures were strong enough to change body morphology, but somehow had no effect on psychology and behavior. That would be “neck-down Darwinism.”
Huh. This is an excellent point; I’m now updating in favor of an increased probability for mental sex differences.
I think your post could use a couple citations for this claim. Off the top of my head, this claim may be true for some traits, but I’ve also seen evidence that it is false for others.
I was thinking of a study mentioned in one of Buss’ textbooks, which I unfortunately don’t have at hand right now. I will look up the exact citation.
So, just because we see a certain sort of variation, it doesn’t necessarily strike down the hypothesis of universal, or quasi-universal, evolved human predispositions.
Right. I should have been clearer on this, too. I did not mean to argue that the variation would disprove an evolutionary or biological basis for these traits. Instead, I was using it as a caution against making too many assumptions of specific individuals.
It may have been a bit misplaced in this post, as it’s more of a general caveat about psychological research than a criticism of evpsych in particular: not many results in psychology are truly universal in that you couldn’t find individuals who were counterexamples. I should possibly remove it and make it into its own post.
Agreed. I’m very tired of articles which say “Hey look! There’s a difference” without getting into the amount of individual difference or group overlap.
A simple example is height. On average men are taller than women.
But most of the time making a men=tall, women=short simplification does not make sense. It makes more sense to provide multiple sizes for both women and men.
And if providing only a very limited selection of sizes (e.g. hospital clothing) it makes sense to provide different unisex sizes rather than one for men and one for women.
And while we’re busy being tired, I’m really tired of no research by anybody (so far as I know) about keeping reactions to ideas one has about group differences in proportion to what one actually knows instead of exaggerating the size or extent of the differences.
It took rather a lot of hammering to get to the idea of atypical women.
That sort of information can only be found by ordinary empirical research,
Certainly. But don’t evolutionary psychologists know this? And I’m talking about what evolutionary psychologists write in peer-reviewed publications, not speculation in popular books.
and ordinary empirical research doesn’t need evolutionary psychology for anything else than suggesting interesting hypotheses
No, but your language here seems a bit strange, because a method for generating interesting hypothesis is a really important part of science. Having great procedures for testing ideas is no use if you have no ideas.
It seems that the ideal evolutionary psychology research paper would start with some well-known fact about human nature—a fact empirically verified by ordinary psychologists. From this fact, plus the fact of evolution under natural selection, plus the fact that none of our fellow apes exhibit this human idiosyncrasy, the paper would infer some hypothesis about our recent selective environment—a plausible hypothesis, given what we already know from physical anthropology. Then, assuming that our hypothesis about the past is true, the paper would reason forward to some new, previously unsuspected hypothetical fact about modern human nature. Finally, the paper would conclude with new empirical research showing that human nature really is like that. A hypothesis about the present generated by evolutionary psychology is found to be true by the methods of ordinary psychology.
That would be great. That would be science. Does anyone have a citation to such a paper?
It seems that the ideal evolutionary psychology research paper would start with some well-known fact about human nature—a fact empirically verified by ordinary psychologists. From this fact, plus the fact of evolution under natural selection, plus the fact that none of our fellow apes exhibit this human idiosyncrasy, the paper would infer some hypothesis about our recent selective environment—a plausible hypothesis, given what we already know from physical anthropology. Then, assuming that our hypothesis about the past is true, the paper would reason forward to some new, previously unsuspected hypothetical fact about modern human nature. Finally, the paper would conclude with new empirical research showing that human nature really is like that. A hypothesis about the present generated by evolutionary psychology is found to be true by the methods of ordinary psychology.
That would be great. That would be science. Does anyone have a citation to such a paper?
What do you think of the experiment cited in this post of Eliezer’s?
Ah, but why do women have less strength, and men have more?
I’ve seen one source claim that people of the same size with the same training will end up with the same strength. The book I’ve gotten it from shows signs of a lot of research (who knew there’d been so much research on sex differences in throwing?), but I’ve got the claim filed under “very interesting if true, wait on more evidence”. And of course, there are average size differences between men and women.
I have no idea whether height differences are a result of arbitrary sexual selection. It’s fading a little, I think, but there’s a cultural assumption that in couples, the man should be taller than the woman.
Again, it’s been faded somewhat, but there’s been a strong cultural assumption, not just that men and women are mentally different from each other, but that they should be different, that men and women should be fairly close examples of ideal types. This means that some fraction of behavior is going to be the result of cultivation rather than genetically forced.
I haven’t seen any discussion of why men and women aren’t more different than they are. As species go, humans are only fair-to-middling sexually dimorphic.
People of the same size with the same training do not end up with the same strength; look at the scoresheet for a powerlifting meet. A 135-pound man is stronger than a 135-pound woman who trains exactly the same way. Hormonally, men are set up to have a higher percentage of muscle mass. I don’t know enough biology to describe it in more concrete detail, though.
Edit: I assume everyone knows enough stats to understand that this does not mean a female athlete can’t outperform most men. I’m also not saying that women shouldn’t challenge themselves athletically. I like the general thesis of “The Frailty Myth” and I think women could be better off training a lot harder than they generally do at present, and that a certain amount of female physical weakness is self-imposed. But there’s also a biological difference.
Your title “Problems in Evolutionary Psychology” is a bit ambiguous. Does it mean problems with the field of evolutionary psychology, or does it mean problems in the field of evolutionary psychology that evolutionary psychologists themselves are grappling with?
This post introduces some of the issues in studying evolutionary psychology, but off the top of my head, my reading on the subject suggests that evolutionary psychologists are aware of most of them and have taken them into account. So the second meaning would make more sense to me.
Either way, I think it would be useful to discuss what evolutionary psychologists think are the inherent difficulties in their fields (and how they propose to deal with them), and how they answer broad criticisms directed at the field. Evolutionary psychologists have been criticized a lot, and have spilled gallons of ink explaining their views in journals. I will try to find something that’s a good introduction and that isn’t behind a paywall.
Could you give an example of someone making this error?
Ah, but why do women have less strength, and men have more? See the excerpts from David Geary’s Male, Female here arguing that greater male strength is related to sexual selection. (The mere fact that females have the babies isn’t enough, because many monogamous primates exhibit minimal dimorphism.)
We know that there were different selection pressures on men and women. It doesn’t make sense to believe that these selection pressures were strong enough to change body morphology, but somehow had no effect on psychology and behavior. That would be “neck-down Darwinism.”
Of course, it is hard to tell whether a present-day sex difference is an adaptation, or not. A lot of arguments that X is or isn’t an adaptation seem too black-and-white; instead, we should be talking about probability that a trait is an adaptation. In many cases, evolutionary psychology has made predictions based on hypothesized adaptations, which have turned out to be true, especially in the area of mating preferences. I’ll try to get some citations for you. These findings should lead us to increase our probability estimates that such behaviors are related to adaptations.
I think your post could use a couple citations for this claim. Off the top of my head, this claim may be true for some traits, but I’ve also seen evidence that it is false for others.
It’s true that there is variation. Though variation needs to be investigated further before it tells us much about the plausibility of evolutionary hypotheses. Evolutionary accounts have many reasons to predict variation, e.g. frequency-dependent selection.
Furthermore, some of the examples you describe may be related to biological but non-evolutionary factors. There is evidence that prenatal hormones influence human psychology. Many factors can influence the prenatal environment, such as maternal stress.
So, just because we see a certain sort of variation, it doesn’t necessarily strike down the hypothesis of universal, or quasi-universal, evolved human predispositions. Prenatal factors can counter-act or modify evolved predispositions. Of course, we shouldn’t hand-wave any variation by saying “that’s just prenatal noise;” we need actual evidence suggesting that variation in a trait is prenatal. And for some items on your list, that evidence exists, so that variation doesn’t cast much doubt on the plausibility of a high evolved similarity in human psychology.
Certainly. But don’t evolutionary psychologists know this? And I’m talking about what evolutionary psychologists write in peer-reviewed publications, not speculation in popular books.
No, but your language here seems a bit strange, because a method for generating interesting hypothesis is a really important part of science. Having great procedures for testing ideas is no use if you have no ideas.
To me, that quote sounds something like saying “boats don’t need navigators for anything else than finding where they are going at sea.”
Robin Hanson does this on a pretty regular basis. Most of his reasoning about gender is based on a male provider, female nurturer model. He is very much not alone.
I should have made it more clear in the post that the primary target of the post was not professional, academic evolutionary psychology. Rather, I was primarily cautioning amateurs (such as LW regulars) about some of the caveats involved in evpsych and noting the rigor required for good theories. While the post does also serve as a warning to be cautious about sloppy research (or sloppy science journalism) that doesn’t seem to be taking these issues into account, I don’t question the claim that the people doing serious evpsych are aware of all the issues I mentioned, and are probably taking them into account.
My wording was probably a bit too strong. Anyway, I’ll try to look up some examples once I wake up.
Huh. This is an excellent point; I’m now updating in favor of an increased probability for mental sex differences.
I was thinking of a study mentioned in one of Buss’ textbooks, which I unfortunately don’t have at hand right now. I will look up the exact citation.
Right. I should have been clearer on this, too. I did not mean to argue that the variation would disprove an evolutionary or biological basis for these traits. Instead, I was using it as a caution against making too many assumptions of specific individuals.
It may have been a bit misplaced in this post, as it’s more of a general caveat about psychological research than a criticism of evpsych in particular: not many results in psychology are truly universal in that you couldn’t find individuals who were counterexamples. I should possibly remove it and make it into its own post.
Given two groups there are probably mental differences.
More interesting is are the distributions bimodal and how much have they changed in e.g. last 100 years.
If the distributions are not bimodal or change relatively strong with time then a simplistic view of “women X, men Y” won’t work.
Agreed. I’m very tired of articles which say “Hey look! There’s a difference” without getting into the amount of individual difference or group overlap.
I agree. I’m also tired of “Hey look! There’s overlap between the distributions, so let’s pretend the difference doesn’t matter!”
A simple example is height. On average men are taller than women.
But most of the time making a men=tall, women=short simplification does not make sense. It makes more sense to provide multiple sizes for both women and men.
And if providing only a very limited selection of sizes (e.g. hospital clothing) it makes sense to provide different unisex sizes rather than one for men and one for women.
And while we’re busy being tired, I’m really tired of no research by anybody (so far as I know) about keeping reactions to ideas one has about group differences in proportion to what one actually knows instead of exaggerating the size or extent of the differences.
It took rather a lot of hammering to get to the idea of atypical women.
It seems that the ideal evolutionary psychology research paper would start with some well-known fact about human nature—a fact empirically verified by ordinary psychologists. From this fact, plus the fact of evolution under natural selection, plus the fact that none of our fellow apes exhibit this human idiosyncrasy, the paper would infer some hypothesis about our recent selective environment—a plausible hypothesis, given what we already know from physical anthropology. Then, assuming that our hypothesis about the past is true, the paper would reason forward to some new, previously unsuspected hypothetical fact about modern human nature. Finally, the paper would conclude with new empirical research showing that human nature really is like that. A hypothesis about the present generated by evolutionary psychology is found to be true by the methods of ordinary psychology.
That would be great. That would be science. Does anyone have a citation to such a paper?
What do you think of the experiment cited in this post of Eliezer’s?
I’ve seen one source claim that people of the same size with the same training will end up with the same strength. The book I’ve gotten it from shows signs of a lot of research (who knew there’d been so much research on sex differences in throwing?), but I’ve got the claim filed under “very interesting if true, wait on more evidence”. And of course, there are average size differences between men and women.
I have no idea whether height differences are a result of arbitrary sexual selection. It’s fading a little, I think, but there’s a cultural assumption that in couples, the man should be taller than the woman.
Again, it’s been faded somewhat, but there’s been a strong cultural assumption, not just that men and women are mentally different from each other, but that they should be different, that men and women should be fairly close examples of ideal types. This means that some fraction of behavior is going to be the result of cultivation rather than genetically forced.
I haven’t seen any discussion of why men and women aren’t more different than they are. As species go, humans are only fair-to-middling sexually dimorphic.
People of the same size with the same training do not end up with the same strength; look at the scoresheet for a powerlifting meet. A 135-pound man is stronger than a 135-pound woman who trains exactly the same way. Hormonally, men are set up to have a higher percentage of muscle mass. I don’t know enough biology to describe it in more concrete detail, though.
Edit: I assume everyone knows enough stats to understand that this does not mean a female athlete can’t outperform most men. I’m also not saying that women shouldn’t challenge themselves athletically. I like the general thesis of “The Frailty Myth” and I think women could be better off training a lot harder than they generally do at present, and that a certain amount of female physical weakness is self-imposed. But there’s also a biological difference.