It’s simple, really. Evolutionary psychology evolved to provide a niche for the evolutionary psychology douchebag.

And that article further provides a niche for all the evolutionary psychology douchebags who are nesting in the comments, oblivious to how tired their songs are.

I previously addressed the criticisms of my criticisms of evolutionary psychology by Jerry Coyne; Now I turn to the criticisms of my criticisms he solicited from Steven Pinker. This is getting a bit convoluted, so let me first state the basics.

I dislike evolutionary psychology. Pinker is an advocate for evolutionary psychology. What brought on this back-and-forth was that I was a member of a panel at a science fiction convention that discussed evo psych; I made a few brief comments on my blog that were capsule summaries of my discussion there. In the section below, the paragraphs preceded by an “M:” and in italics are my words excerpted from those comments; the parts preceded by a “P:” are Pinker’s commentary. All clear?

M: Fundamental assumptions of evo psych: That you can infer an adaptive history from the distribution of current traits — that they are adaptations at all is an assumption usually not founded in evidence (this is not to deny that that there are features that are clearly the product of selection, but that you can’t pick an arbitrary attribute and draw elaborate scenarios for its origins). . .

P: Of course “arbitrary” and “elaborate” are the straw-man giveaways here. What about carefully selected attributes, and minimal assumptions about phylogeny with a focus on function, as we do for other organs? You can ask what the spleen is for – and it would be perverse to do physiology without asking such a question – without “drawing elaborate scenarios for its origins.”

Whoa, whoa, whoa — that skips right over the really important word: “adaptive”. Start there. That’s my primary objection, the habit of evolutionary psychologists of taking every property of human behavior, assuming that it is the result of selection, building scenarios for their evolution, and then testing them poorly.

We already know that that is impossible. The repertoire of human behavior is so complex and rich, and relatively recently evolved, that to argue that every behavior is the product of specific selection imposes an untenable genetic load. The bulk of the genetic foundation of our psychology (and I agree that there must be one!) must be byproducts and accidents. The null hypothesis of evolutionary psychology should be that a behavior is non-adaptive, yet for some reason all I ever see is adaptive hypotheses.

The spleen is an interesting example. There are components of the spleen that are definitely functional and almost certainly adaptive: its functions as a blood reservoir, as an element of the immune system, as part of the erythrocyte cycling mechanism. You can examine the evolution of those functions phylogenetically; for instance, some teleosts lack the erythropeotic functions of the spleen, while the majority use it as a blood reservoir. You can begin to dissect its history comparatively, by looking at what has a clear functional role and looking at the pattern of emergence of those properties.

What you can’t do is pick any particular property of the spleen and invent functions for it, which is what I mean by arbitrary and elaborate. For instance, the spleen is located in most people in the upper left quadrant of the abdomen; are you going to make an adaptive case for why it’s on the left rather than the right? The actual reason almost certainly has nothing to do with adaptation or selection, and everything to do with historical and developmental mechanisms that are neutral with respect to selection.

M:. . . That behavioral features that have been selected for in our history are represented by modular components in the brain – again with rare exceptions, you can’t simply assign a behavioral role to a specific spot in the brain, just as you can’t assign a behavior to a gene.

P: No one in Ev Psych points to specific spots in the brain – that’s cognitive neuroscience, not evolutionary psychology. The only assumption is that there are functional circuits, in the same way that a program can be fragmented across your hard drive.

Now this is one of my peeves with evolutionary psychology. The evo psych literature is thick with papers emphasizing “modularity”; that evolutionary psychology FAQ I referenced before makes it clear that it’s an important concept in the field (and also ties it to concepts in computer science). Yet it is meaningless. Sometimes there’s the implication that the “module” is a discrete element in the brain, but it’s never clear whether they’re talking about a genetic module (an epistatic network of genes) or a neural module (an interconnected network of neurons), and when pressed, they retreat, as Pinker does here, to an admission that it could be just about anything scattered anywhere in the brain.

So my question is…why talk about “modules” at all, other than to reify an abstraction into something misleadingly concrete? Evolutionary psychologists don’t do neurobiology, and they don’t do genetic dissections, and they don’t do molecular genetics, so why do they insist on modularity? It’s premature and a violation of Occam’s razor to throw the term around, and also completely unnecessary — a behavior could be a product of diffuse general phenomena in the brain without diminishing its importance at all.

M: . . . That the human brain is adapted to a particular environment, specifically the African savannah, and that we can ignore as negligible any evolutionary events in the last 10,000 years, that we can ignore the complexity of an environment most of the evo psych people have never seriously studied, and that that environment can dictate one narrow range of outcomes rather than permit millions of different possibilities.

P: The savannah is a red herring – that’s just a convenient dichotomization of the relevant continuum, which is evolutionary history. A minimal commitment to “pre-modern” gives you the same conclusions. By saying that the brain could not have been biologically adapted to stable government, police, literacy, medicine, science, reliable statistics, prevalence of high-calorie food, etc., you don’t need to go back to the savannah; you just need to say that these were all relevantly recent in most people’s evolutionary history. The savannah is just a synechdoche.

Ah, a synechdoche. This is the evolutionary psychology version of the religious argument that it’s “just a metaphor.”

Again, this is a peeve I have with the field. I agree with the general principle that of course the brain is a product of our evolutionary history, and that there is almost certainly a foundation of genetically defined, general psychological properties of the mind…and that a great many specific psychological properties are not biologically adapted. Pinker is writing good common sense here.

But over and over, you see evolutionary psychologists falling into this trap of examining a behavior and then fitting it to some prior specific environment. They talk of a Savannah Mind or they generalize it to the Environment of Evolutionary Adaptedness. It’s another reification of the unknown. You don’t like “savannah”? Change it to “Pleistocene”. It’s just as broad and meaningless. It’s an attempt to reduce the complex and diverse to a too simple unit.

M: I’d also add that most evo psych studies assume a one-to-one mapping of hypothetical genes to behaviors. . .

P: Completely untrue – this was Gould’s claim in the 1970s, which confused a “gene for x” (indispensable in any evolutionary thinking, given segregation) in the sense of “increases the probability of X, averaging over environments and other genes” with “a gene for X” in the sense of “necessary and sufficient for X.” Every honest biologist invokes “gene for X” in the former sense; evolution would be impossible if there were no additive effects of genes. No one believes the latter – it’s pure straw.

By one-to-one, I mean the assumption that a behavior trait can be mapped to a contribution from a gene that was subject to selection for that trait; that it might be an additive property of a pleiotropic gene will be nominally noted, as Pinker does here, but operationally ignored. Remember, the issue is not whether genes contribute to our psychology, a point I totally agree with, but whether we can assign a selective origin to a behavior. That is a much, much harder problem.

M [continuation of previous sentence]:. . . and never actually look at genes and for that matter, ignore most human diversity to focus on a naive typological simplicity that allows them to use undergraduate psych majors at Western universities as proxies for all of humanity”

P: It’s psychologists, not evolutionary psychologists, who focus on Western undergrads –field research and citations of anthropology are vastly more common in ev psych than in non-ev-psych. PZ is engaging in prosecution here, not analysis – he’s clearly ignorant of the sociology of the fields.

As for diversity – is he arguing for genetic differences among human groups, a la Herrnstein & Murray?

First, this has already been addressed by Stephanie Zvan: when you look in the evolutionary psychology journals at papers identified as evolutionary psychology, you find…a focus on Western undergrads. I throw up my hands in exasperation. Look at the actual work done in your field, not the abstract ideal you hold in your head. I get my vision of evolutionary psychology by reading the papers.

Secondly, what a weirdly off-target attempt at ad hominem. Once again, my criticisms are being addressed by imagining motives; in Jerry Coyne’s critique, I’m an uber-liberal offended at the consequences a genetic component to behavior might have on my egalitarian biases; now Pinker takes a swipe by tarring me with the likes of Herrnstein & Murray. Make up your minds!

For the record, of course there are genetic differences in human populations! It’s an open question whether any of them make significant contributions to human psychology, however. I’m open to evidence either way.

But my remark was about cultural diversity (which also, by the way, exists). Setting aside the notion of a genetic component for now, we know that culture creates different minds. How can you analyze the causes of a behavior if your work focuses on a relatively uniform sample?

M: Developmental plasticity vitiates most of the claims of evo psych. Without denying that some behaviors certainly have a strong biological basis, the differences in human behaviors are more likely to be a product of plasticity than of genetic differences. . .

P: Plasticity is just learning at the neural level, and learning is not an alternative to innate motives and learning mechanisms. Plasticity became an all-purpose fudge factor in the 1990s (just like “epigenetics” is today). But the idea that the brain is a piece of plastic molded by the environment is bad neuroscience. I reviewed neural plasticity in the chapter “The Slate’s Last Stand” in The Blank Slate, with the help of many colleagues in neuroscience, and noted that the plasticity that allows feedback during development and learning during ontogeny is superimposed on an innate matrix of neural organization. For example if you silence *all* synaptic activity in the brain of a developing mouse with knock-outs, the brain is pretty much normal.

Speaking of straw men…I found The Blank Slate entirely unreadable, unlike most of Pinker’s books, because of the gigantic straw man erected in the title. This flailing against me is a product of this weird idea that I reject the contribution of our genes to our minds, but just as there are no evolutionary psychologists who believe everything in our brains is genetically predetermined, there is no such thing in serious science as a “blank slater”.

There is a continuum, and we’re arguing about degrees. For example, take a child of French parents and raise them in the United States, they’ll grow up speaking fluent English (or Spanish, depending on the household), and vice versa — an American child raised in France will speak French like a native. There is no genetic component to the details of language. Yet when you compare diverse languages you can start to pick out commonalities, and when you look at the neural substrates of language you do see shared anatomy and physiology — I do not hesitate to accept that there is an evolved component of human language. The differences between speakers are learned, the universals may well be biological.

Which means that when evolutionary psychologists try to parse out variations between different groups, racial or sexual, I suspect it’s most likely that they are seeing cultural variations, so trying to peg them to an adaptive explanation is an exercise in futility. When evolutionary psychologists try to drill down and identify the shared components, I’m much more willing to see their efforts as interesting.

That last sentence by Pinker is a lovely example of nonsensical denial of the importance of plasticity. “Pretty much normal” means that on broad, superficial inspection the various components of the brain are present — hindbrain, midbrain, forebrain, various nuclei and pathways, they’re all there. I’ve seen the same thing in zebrafish: the peripheral motor nerves I studied as a graduate student form perfectly normally even if you knock out all the acetylcholine receptors, so that the muscles are totally unresponsive to physiological inputs.

This does not surprise me. Most of the patterning of the brain is set up in the embryo before neuronal connectivity is established; the clock-like activity of mitotic rate genes defines the size of various bits of the brain; adhesive and repulsive cell surface interactions lay out the major pathways. Does Pinker think someone trained in developmental neurobiology would expect that the brain would collapse into a formless blob in the absence of action potentials and synaptic transmission?

But it is still absurd to call the deprived brain “pretty much normal”. When you look deeper, you find subtle and important differences. The clearest examples are found in experiments with visually deprived cats: sew one eyelid shut, or both, or alternate, in a young kitten, and you can find all kinds of changes in visual processing, detectable at both the physiological and anatomical levels. The visual cortex forms, projections from the lateral geniculate terminate in roughly the right place, but they absolutely depend on visual input to fine tune their connections. Human children born with visual deficits in one eye will also have lifelong deficits in visual processing, even if the original problem is corrected.

Try raising a child without contact with other humans. I guarantee you that their brains, when physically examined, would look “pretty much normal”…but does anyone really believe that psychologically, on the level evolutionary psychologists study brains, that they’d be “pretty much normal”?

This is “pretty much normal” behavior from evolutionary psychologists, though. Point out that that their inferences about neuronal circuitry are bogus, they tell you that they don’t study neurons anyway; tell them that the behaviors they study are awfully plastic and flexible, and presto, hey, look, brains and neurons are patterned by genetic elements. The sleight of hand is impressive, except when you realize that science shouldn’t be about magic tricks.

I have disturbed and distressed Jerry Coyne, because I have dissed the entire field of evolutionary psychology. I find this very peculiar, because in my field, Jerry Coyne has a reputation for dissing all of evo devo, so it can’t possibly be that we’re supposed to automatically respect every broad scientific endeavor. There has to be something more to it than just an academic defense of a discipline. And there is, unfortunately. Here’s his prelude.

I’ve been known for a while as a critic of evolutionary psychology, particularly when it first began as “sociobiology” in the Seventies. At that time there was a lot of unsupported speculation being bruited about as “science” (i.e., human males evolved to have “rape modules”, a view that I criticized strongly). But over the decades, evolutionary psychology has matured, and I now see it as a valuable way of studying the origins of human behavior. Not that it’s all perfect—the “pop” versions, such as those produced by Satoshi Kanazawa, seem pretty dire to me, debasing a field that’s striving for scientific rigor. But even Kanazawa has been rejected by serious evolutionary psychologists.

Sadly, some self-professed skeptics have decided to debunk the entire field of evo-psych, and for reasons that I see not as scientific, but as ideological and political. That is, like the opponents of sociobiology thirty years ago, these skeptics object to the discipline because they see it as both motivated by and justifying conservative political views like the marginalization of women. Well, that may be the motivation of some people, but not, I think, of most well-known workers in evo psych, who are merely trying to study the evolutionary roots of human behavior. It pains me that skeptics are so dogmatic, so ideological, in viewing (and rejecting wholesale) a legitimate scientific field.

That second paragraph? Pure ad hominem, unsupported by evidence. I detest evolutionary psychology, not because I dislike the answers it gives, but on purely methodological and empirical grounds: it is a grandiose exercise in leaping to conclusions on inadequate evidence, it is built on premises that simply don’t work, and it’s a field that seems to do a very poor job of training and policing its practitioners, so that it primarily serves as a dump for bad research that then supplies tabloids with a feast of garbage science that discredits the rest of us. I’d like to see the evolutionary psychologists who propose that there is a high quality core to their discipline spending more effort ripping into their less savory colleagues than on the indignant sniffing at critics of evolutionary psychology. I’d have more respect for the field if there was more principled internal striving.

There is also a tactic I really dislike; I call it the Dignified Retreat. When criticized, evolutionary psychologists love to run away from their discipline and hide in the safer confines of more solidly founded ideas. Here’s a perfect example:

…the notion that “the fundamental premises of evo psych are false” seems deeply misguided. After all, those premises boil down to this statement: some behaviors of modern humans reflect their evolutionary history. That is palpably uncontroversial, since many of our behaviors are clearly a product of evolution, including eating, avoiding dangers, and the pursuit of sex. And since our bodies reflect their evolutionary history, often in nonadaptive ways (e.g., wisdom teeth, bad backs, the coat of hair we produce as a transitory feature in fetuses), why not our brains, which are, after all, just bits of morphology whose structure affects our behaviors?

You know what? I agree entirely with that. The brain is a material product of evolution, and behavior is a product of the brain. There are natural causes for everything all the way down. And further, I have great respect for psychology, evolutionary biology, ethology, physiology, anthropology, anatomy, comparative biology — and I consider all of those disciplines to have strong integrative ties to evolutionary biology. Does Coyne really believe that I am critiquing the evolved nature of the human brain? Because otherwise, this is a completely irrelevant statement.

Evolutionary psychology has its own special methodology and logic, and that’s what I criticize — not anthropology or evolutionary biology or whatever. Somehow these unique properties get conveniently jettisoned whenever a critic wanders by, only to be re-adopted without reservation within the exercise of the discipline. And that’s really annoying.

What I object to in evolutionary psychology is that their stock in trade is to make observations of behavior in a single species, often in a single population, and then to infer an evolutionary history from that data point. You don’t get to do that. It’s not that the observations are invalid (they’re often interesting in their own right), or that it’s not possible that human behaviors carry a strong genetic component — it’s that you simply can’t draw an evolutionary conclusion from the simple existence of a trait in a population. Yet evolutionary psychologists do, all the time.

I had a second objection that Coyne briefly addresses: developmental and neuroplasticity obscure the genetic basis of behaviors.

… “developmental plasticity” does not stand as a dichotomous alternative to “evolved features.” Our developmental plasticity is to a large extent the product of evolution: our ability to learn language, our tendency to defer to authorities when we’re children, our learned socialization—those are all features almost certainly instilled into our brains by natural selection as a way to promote behavioral flexibility in that most flexible of mammals.

That’s a cop-out. Yes, developmental plasticity is an evolved property, but to study it, you study development. Not psychology. It’s a different level of the problem.

The reason plasticity is a serious (and far too ignored) issue for evolutionary psychology is that if you’re trying to identify a genetic basis for a specific behavior, it represents a huge amount of confounding noise. It’s HARD WORK to isolate the genetic core of a behavior (assuming there is one) from the learned properties of the organism.

For instance, I’m really interested in the behaviors of zebrafish, and one of the things I’ve done is tried to identify different behaviors in different lines of fish — they exist, and it would be really cool to identify alleles involved in the differences. Feeding behaviors, for instance, vary in different lines. One line may carry out what we think are wild-type patterns: they feed by darting to the surface, carrying the food down to the bottom, and gulping it down there. Another may indulge in stupid lab-bred behaviors: wallowing at the surface, chowing down on floating flakes — something that would get them eaten quickly by birds in the wild.

It turns out to be really hard to maintain that behavior in the lab. Raising fry to adults is actually a wonderful exercise in selection (wallowing babies get lots of food, cautious babies get less) and training. We really had to struggle to develop feeding regimens that were neutral to the behavior we wanted to study. That’s why plasticity is such an important factor in these kinds of studies — it’s really, really, really hard to separate learned behavior from genetically predisposed behavior. It demands a huge amount of rigor and all kinds of controls — the kinds of things you simply cannot do with humans.

Again, this is not to say that one can’t do good psychology. What I’m saying is that taking that next huge step of linking behavior to genes to evolution demands data and methods that are not present in our toolbox right now, making most of the claims of evo psych fallacious.

In our presentation at Convergence, Greg Laden mentioned being present at early seminars by Cosmides and Tooby in which they laid out their goals. They drew a big box and in one top corner, they wrote “behavior”; in a lower corner, they put “genes”. The idea was that this field would strive to connect the two words together — which I consider a wonderful goal and something I’d like to see, too. Unfortunately, the space between the two words is filled with handwaving right now. I’m much more respectful of science that tries to incrementally bring the two together, but evolutionary psychology prematurely tries to stitch them together with transparent guesswork. That’s not science.

Coyne closes with a couple more ad hominems.

One gets two impressions when listening to the skeptics’ criticism of evolutionary psychology. First, they haven’t read widely in the discipline, and are criticizing either pop-culture versions of the field or a caricature (born of ignorance, possibly willful) of EP. Even I know that EP advocates don’t often publish studies that rely solely on undergraduates.

As I mentioned, I’m very interested in the connection between genes and behavior — I’ve actually read quite a bit in this field. I’ve also read a fair amount of the evolutionary psychology literature, and the source of my animus is that in comparison to good science on the biological basis of behavior, it suffers abominably. It doesn’t even come close to evolutionary biology (my own work is more genetics and brain development, and I’ll be the first to tell you that work on lab-bred zebrafish is a piss-poor way to do evolution…so I find it particularly appalling to see human psychology touted as evolutionary).

As for the claim that EP doesn’t often publish studies solely on undergraduates — it’s worse. Stephanie Zvan looked at recent publications in the journal Evolutionary Psychology.

How many of these studies were done only using college students? More than half. In 33 studies, the population whose preferences were used as a proxy for human universals was a population of college students. Another six studies used a combination of college students and other populations. One of these additional study populations was young, educated Israeli adults. Two were populations from around the university attended by the student populations.

Other university town populations were used on their own, without student populations, but many of the studies that did not use college students could not. Studies of blind dates, cyclists, criminals, pregnant women, sleep deprivation, parents of premature babies, younger children, soccer referees, musicians, and severely disabled people all drew from specialized populations.

More striking than the use of college students, however, was the geographic restriction on the populations used. Out of 60 studies, 51 drew their samples entirely from the U.S., Canada, and Europe. The exceptions were (mostly students) from Japan, Singapore, China, Israel, World Cup countries, St. Kitts, Mexico, historical records from around the world, and an international sample drawn from Amazon’s Mechanical Turk. While not all the samples were “Western” (in the odd, non-directional meaning that word has accrued), only those last four–7% of the total–were distinctly non-WEIRD.

Ooops. Really, look over the papers — they’re already restricted to one species, and it’s an exceptional work that even tries to reach out to different subpopulations. The study of the genetic basis of behavior is an extraordinarily complex problem, and I don’t see any adequate efforts being made to constrain the variables; and once you’ve got a genetic basis, identifying an evolutionary history for that is yet another non-trivial problem.

And then we get the ideology-bashing again.

Second, it’s pretty clear that the opposition to evolutionary psychology from these quarters is ideologically rather than scientifically motivated. One gets the feeling that research on gender differences shouldn’t be done at all because it’s either designed to repress women, motivated by the desire to do that, or has the likely outcome of promoting discrimination. Well, sexist scientists may try to do that, but I haven’t seen much of that since the Seventies. And gender differences are fascinating. There’s a reason, for instance, why human males are larger and hairier than females, and have more testosterone. Are we supposed to say “You can’t work on that—could have bad repercussions!” Sure, scientific results can always be misused, but I don’t see that as a reason to put up roadblocks against scientific research. After all, what field is more misused and misquoted than evolutionary biology? I am a frequent recipient of emails from Jews trying to convince me to reject evolution because Darwin ultimately caused the Holocaust.

Please. Have I ever said that we shouldn’t study gender or racial differences? No. We know there are going to be differences. The catch is that they have to be studied very, very well, with rigor and careful analysis, because they are socially loaded and because science has a deeply deplorable history of using poor methods to reach bad conclusions that are used as ideological props for the status quo. I’m not putting up roadblocks against scientific research; I would like to put up roadblocks to sloppy, lazy ideological nonsense touted as scientific research. I should think every scientist would want that.

To return to Coyne’s prior criticism of evo devo: that’s exactly what I appreciated about it. He took a strong stance, demanding hard evidence to support evo devo’s claims of the importance of regulatory mutations in evolution. And he was right to do so! If you’re going to make claims about genes and evolution, you had better be prepared to show the supporting evidence at all levels of the problem. I’m not sure why he’s gotten more soft on the demand for rigor from evolutionary psychology when he was far more demanding on evo devo.

Maybe it was ideology.

And this is just silly.

…the fundamental premise of evolutionary psychology is absolutely sound: our brains, like the rest of our bodies, are the product of evolution and natural selection over the past six million years, and some of our current behaviors reflect that evolution. To deny that is ideologically motivated nonsense. To parse out the evolutionary component of such behaviors is the goal of evolutionary psychology.

That’s another Dignified Retreat. Evolutionary Psychology is not synonymous with Evolutionary Biology. I can reject bad science in the form of evolutionary and genetical claims about behavior; it does not imply that I think evolution played no role in our brains.

Coyne has a long section where he solicited responses from Steven Pinker, as well. This is long enough so I’ll defer that for a different day, but I did note that there’s a lot of this ideological ad hominem in there, too, and some of it is even contradictory!

It is a very good and measured response that highlights the flaws in bad evolutionary psychology.

Evolutionary psychology, the study of human psychological adaptations, does not have a popular or scientific reputation for being rigorous, even though there are rigorous, thoughtful scientists in the field. The field is trying to take on an incredibly challenging task: understand what of human behavior is adaptive and why. We can better circumvent the conditions that lead to violence, war, and hatred if we know as much as we can about why we are the way we are. What motivates us, excites us, angers us, and how can evolutionary theory help us understand it all?

Because of this, there are consequences to a bad evolutionary psychology interpretation of the world. The biggest problem, to my mind, is that so often the conclusions of the bad sort of evolutionary psychology match the stereotypes and cultural expectations we already hold about the world: more feminine women are more beautiful, more masculine men more handsome; appearance is important to men while wealth is important to women; women are prone to flighty changes in political and partner preference depending on the phase of their menstrual cycles. Rather than clue people in to problems with research design or interpretation, this alignment with stereotype further confirms the study. Variation gets erased: in bad evolutionary psychology, there are only straight people, and everyone wants the same things in life. Our brains are iPhones, each app designed for its own special adaptive purpose.

I’ve still got plans to post more on this subject, but an unfortunate event has blocked me. I was going to make my next post on evolutionary psychology one that focused on some of the papers, and in particular, I wanted to discuss a good paper or two, so that I could start off on the right tone. And people sent me links and papers.

Only problem: they were all awful. Every one. I couldn’t believe that even these papers that some people were telling me were the best of the bunch were so lacking in rigor and so rife with unjustified assumptions. I read through about a dozen before I gave up in disgust and decided that there were better things to do in my time.

I’d ask again, but I was burned so badly on that last go-round that I’d have a jaundiced view of any recommendation now.