Wednesday, December 24, 2008

Pop Evolutionary Psychology

David J. Buller is a Professor of Philosophy at Northern Illinois University (USA). He is an expert in his field, He is not a professional science journalist although he has written a book and many articles.

This is relevant because many science journalists have written favorable articles about popular evolutionary psychology. This is the field that promotes evolutionary explanations for many human behaviors. They are the classic examples of adaptationist just-so stories.

Buller has just published an article in Scientific American where he argues against these popular stories [Evolution of the Mind: 4 Fallacies of Psychology].

Here's part of what he says ...
Some evolutionary psychologists have made widely popularized claims about how the human mind evolved, but other scholars argue that the grand claims lack solid evidence


The most notable representatives of Pop EP are psychologists David M. Buss (a professor at the University of Texas at Austin and author of The Evolution of Desire and The Dangerous Passion) and Steven Pinker (a professor at Harvard University whose books include How the Mind Works and The Blank Slate). Their popular accounts are built on the pioneering theoretical work of what is sometimes referred to as the Santa Barbara school of evolutionary psychology, led by anthropologists Donald Symons and John Tooby and psychologist Leda Cosmides, all at the University of California, Santa Barbara.

According to Pop EP, “the human brain consists of a large collection of functionally specialized computational devices that evolved to solve the adaptive problems regularly encountered by our hunter-gatherer ancestors” (from the Web site of the Center for Evolutionary Psychology at U.C.S.B.). Just as evolution by natural and sexual selection has endowed all humans with morphological adaptations such as hearts and kidneys, Pop EP says, so it has endowed all humans with a set of psychological adaptations, or “mental organs.” These include psychological mechanisms, or “functionally specialized computational devices,” for language, face recognition, spatial perception, tool use, mate attraction and retention, parental care and a wide variety of social relations, among other things. Collectively, these psychological adaptations constitute a “universal human nature.” Individual and cultural differences are, by this account, the result of our common nature responding to variable local circumstances, much as a computer program’s outputs vary as a function of its inputs. The notable exceptions to this rule involve sex differences, which evolved because males and females sometimes faced distinct adaptive problems.

Moreover, because complex adaptation is a very slow process, human nature is designed for the hunter-gatherer lifestyle led by our ancestors in the Pleistocene (the period from 1.8 million to 10,000 years ago). As Cosmides and Tooby colorfully say, “our modern skulls house a Stone Age mind.” Pop EP proposes to discover our universal human nature by analyzing the adaptive problems our ancestors faced, hypothesizing the psychological mechanisms that evolved to solve them and then testing those hypotheses using standard-fare psychological evidence, such as paper-and-pencil questionnaires. Pop EP claims that a number of psychological adaptations have been discovered in this way, including evolved sex differences in mate preferences (males prefer nubility; females prefer nobility) and jealousy (men are more distressed by a mate’s sexual infidelity, women by emotional infidelity).

I believe that Pop EP is misguided. The ideas suffer not so much from one fundamental flaw as from many small mistakes. Nevertheless, recent critiques of evolutionary psychology point to some general problems of Pop EP.
There's nothing remarkable about this article. The majority of evolutionary biologists know full well that pop evolutionary psychology is a farce. For most biologists, it's an embarrassment.

The real puzzle is why most science journalists seem to be completely unaware of the controversy. They haven't been doing their job. Next time you see an article promoting the "latest discoveries" of pop evolutionary psychology look for the balance. Do you see the disclaimers questioning the relevance of the entire field? If those points aren't mentioned then you know that science journalists have not done their homework.


  1. I bought that copy of Scientific American to read on the plane ride to my mom's house and I read the article that you linked to.

    Whereas the article doesn't teach YOU anything new, it is valuable for someone like myself who is certainly a non-expert; as a result of reading this article I will certainly be more alert for such nonsense and will know which questions to ask myself.

    I don't know what it is like at a university such as yours, but at mine it is common for non-scientists to make claims on baseless conjecture and pop-evolutionary biology seems to fall within that category.

  2. To quote Jerry Coyne:

    "In science's pecking order, evolutionary biology lurks somewhere near the bottom, far closer to phrenology than to physics. For evolutionary biology is a historical science, laden with history's inevitable imponderables. We evolutionary biologists cannot generate a Cretaceous Park to observe exactly what killed the dinosaurs; and, unlike "harder" scientists, we usually cannot resolve issues with a simple experiment, such as adding tube A to tube B and noting the color of the mixture... If evolutionary biology is a soft science, then evolutionary psychology is its flabby underbelly."

  3. Although, Carlo, to quote Stuart Kauffman:

    "Biology is surely harder than physics."

  4. Jerry Coyne is an ass. There is little difference between historical and non-historicla sciences. Both use the hypothetical-deductive method, as Mayr pointed out. Whether you use a lab coat or collecting data in the field is only a cosmetic difference. Predictions are made and ideas confirmed or discarded accordingly.

  5. Seem slike Coyne cannot trascend an almost creationist-level epistemology: "were you there"?

    As a sample of predicting in historical sciences, a button:

  6. Coyne has made important contributions to the field. He was probably speaking tongue-in-cheek.

  7. Having made important (or not so important) contributions does not give the licence to talk out of your ass.

  8. First off Jerry Coyne's contributions to the fields of speciation and sexual selection (among others) are significant and commendable. Secondly, why not just go read the article I linked to in order to get some context for that quotation? Obviously Dr. Coyne's opinion of his own field of research is not so low...

  9. Yeah, well, there are many, many, many researchers that have made "significant contributions" in the fields of speciation and sexual selection, theoretitically and empirically. There is a lot of niches for studying that, and Coyne is just another in that list. I guess Coyne is a good evolutionary ecologist, but he is no towering figure of evolution.

    Now, i can fully assure you this is by no menas the first time I hear him say something frivolous and stupid, and I very much doubt it will be the last.

  10. I read Buller's article and I think he re-makes some excellent points. I was left with some questions, though:

    Where is the line drawn between silly "pop" EP and the presumably legitimate academic version?

    If the entire field of EP is founded on unjustifiable assumptions, then are scientific questions of human behavioral adaptations:
    a.) unanswerable in principle and therefore not worth asking?
    b.) only legitimate if hypothesized answers do not in any way imply ancestrally inequitable social situations?
    c. ) pointless because of the extreme behavioral plasticity of the amazing human brain? (an argument that seems to me a de facto blank-slate position)
    d.) or what?

    If behavioral ecologists can identify patterns of social and sexual behavior that are consistent among anthropoids, primates, mammals, tetrapods, vertebrates, or animals (draw your own line), is it scientifically justifiable to investigate, as a hypothesis, that pattern in humans? If not, why not?

  11. Sven has a good question, but I doubt he'd like MY answer, hehehe

  12. Let's put it this way...if Jerry were talking about "behavioral ecology", he'd be absolutely right that it is "soft science" and "closer to phrenology than to physics".

  13. Ok, I need to make a precision: by "behavioral ecology" I mean the branch of ecologists that, much like in "evolutionary psychology" call themselves by a very general name, but actually represent only one opinion, an opinion contradicted by dissenting colleagues, which basically ignores the development of behavior by assuming its genetic determination. Gene selection explains the evolution of behavior. And that's it.

    Well, it's not that simple, and other approaches exist (surprise!). In humans, it's called developmental psychology. In general, the term developmental systems biology has been proposed (by Oyama and others). These, of course, are evolutionary explanations, too. At all levels, human or not, the "gene assumption" has been sorely ignoring the complexities of behavioral and phenotypic plasticity.

  14. Yeah, the gene-centric view of evolution is clearly in error. It is a flawed research program.

  15. No doubt there has been tons of research in behavioral ecology. The question is about the QUALITY of this research, which is low, specially given the self-satisfied atitude of this large, well-sustained community of researchers.

    Most of the time it is just observation of a behavior, interpreted as some kind of optimal adaptive solution, and thus "must" be the result of gene selection. But it turns out it is quite often the result of behavioral plasticity, with no gene whatsoever to determining said behavior.

    Other times it is just a measuremnet of heritability of a trait, usually very low (requiring for massive data sets to be detectted statistically) that is taken as evidence that the trait is "genetic"... and thus "must" be under selection. Amateurish stuff

    Rarely are the assumptions put to test by achieving molecular resolution, actual sequences, for the genes "assummed" to be directing behavior

  16. "Sven DiMilo said...

    I read Buller's article and I think he re-makes some excellent points. I was left with some questions, though:

    Where is the line drawn between silly "pop" EP and the presumably legitimate academic version? "

    Can anyone point me toward a serious answer to Sven's question? Most of what I am reading here is academic backbiting. Has someone taken a dispassionate look at all of EP?

    Joseph Osborne

  17. A. Vargas :

    This is true that both historical and experimental sciences aim toward the same goal: finding the best model to explain an ensemble of data.
    The main differences stems from the numbers of possible data: in the field of experimental science, they are much more numerous, because there are no limits (other than fundings) to the possibilities of experimenting, and it is moreover possible to target very specific features of the systems, so that there is much INFORMATION at our disposal for validating our model.

    In the case of historical sciences, the data are much sparser, it is most of the case a question of chance whether or not one finds something relevant for a theory, and in spite of the accumulation of more data with excavations (in the case of history/archeology) , the data are not sufficient for allowing the identification of one precise model, this is why in many fields of history, pluralism is a rule, because many possibilities could be true, and there is no way to differentiate between them-

    Of course, there are several degrees of uncertainty, but in the case of EP, this seems to me to particularly problematic, since, as Jerry Coyne rightly pointed out, "Behaviors don't fossilize", so the few data available let much room for imagination to EPists.
    On the contrary, in fields like experimental chemistry or physic, models and possibilities are much more constrained because of the greater abundance of data.