Robert Kurzban

The Evolutionary Psychology Blog

By Robert Kurzban

Robert Kurzban is an Associate Professor at the University of Pennsylvania and author of Why Everyone (Else) Is A Hypocrite. Follow him on Twitter: @rkurzban

Post 2.0 On Science 2.0

Published 21 December, 2011

Hank Campbell, whose posts I recently discussed, is not the only Science 2.0 blogger with a dim view of evolutionary psychology. In certain respects, Campbell’s enmity for the field (or, I should say, his enmity for his mistaken views of what the field is) is actually somewhat mild compared to those of his Science 2.0 co-blogger Gerhard Adam. In a post from this past summer, Adam discusses evolutionary psychology and what he believes is wrong with the field, focusing on the primer by John Tooby and Leda Cosmides. Below is a sample of quotations regarding Tooby, Cosmides, and evolutionary psychology. All the pronouns in the quotations below refer – sometimes a bit opaquely – to the Tooby and Cosmides piece, in one way or another:

“This kind of statement is simply embarrassing.”

“This statement is simply stupid…”

“This kind of misunderstanding is simply ridiculous.”

“…simply not true.”

“… a uniform failure to understand…”

“… this kind of basic misunderstanding…

“…a fundamental failure to understand evolution and natural selection.”

“…simply idle speculation and nonsense.”

“…certainly can’t be considered scientific.”

Note that Adam does not beg to differ. He doesn’t take a slightly different point of view. And he doesn’t think Tooby and Cosmides might be mistaken to some extent. To read these quotes, you would think that he is criticizing people who are in no way worthy of measured discourse; his interlocutors, to him, are basically abjectly stupid. Morons. Intellectual munchkins. Nincompoops. Science 2.0 bloggers.

And you’d think that Tooby and Cosmides don’t know the first thing about evolution by natural selection, let alone science more generally.

Now, it could be that Adam has correctly identified Tooby and Cosmides as being essentially stupid and ignorant of all things biological. I mean, it could be that their massive scientific success does no more than show that Adam has risen to an intellectual zenith far above the rest of us and is just waaaay smarter than the scientific community that has cited them 20,000 times or so.

I think that there’s another possibility. It could be that Adam is so confused about the facts and the arguments that he perceives Tooby and Cosmides to be stupid – simply stupid, to use one of his favorite modifiers – because he is not in a position to appreciate the material he is trying to understand, a sort of Dunning-Kruger effect. So, it’s worth looking at his critiques to try to figure out if his own confusion about the relevant issues might be responsible for his dim view of the field.

Ok. Well, I’ll just take a few examples. Let’s have a look at his understanding of natural selection, which he claims Tooby and Cosmides fail to understand. He writes that natural selection “ensures that an organism has the necessary traits to survive in the environment in which it exists.”

So, this might be one clue he doesn’t understand natural selection, which he claims Tooby and Cosmides “fundamentally fail to understand.” Natural selection does not ensure that organisms survive, as evidenced by the fact that so many products of natural selection don’t, well, survive.  Natural selection is a process having to do with the differential replication of genes, which is why the emphasis is on reproduction, not survival, and on differential replication, not the notion of necessity. (Gerhard, reading Dawkins’ The Selfish Gene or Dennett’s Darwin’s Dangerous Idea will help you out on this. Both books are written for a broad audience and are quite accessible.)

Continuing on the natural selection line, let me quote one paragraph in its entirety:

In this case, the problem occurs with words like “designed”, because that already indicates a fundamental failure to understand evolution and natural selection.  In the first place, why presume that the brain evolved to “solve problems”?  There are organisms that don’t even have nervous systems that are capable of that function.  More importantly, what problems are so unique to humans that they should be the only species to have “evolved” such a brain?  Considering the simple reality that there are no particularly unique problems that humans solve, then we must conclude that this is an insufficient reason to explain the existence of the human brain.  It is a classic error in assuming that modern day biological structures are necessarily adaptive.  After all, it is equally plausible to assume that brain development diverged due to a random mutation, and that it’s [sic] subsequent benefits moved humans down a different evolutionary path.

Readers of this blog will find much of this laughable without further comment, but I thought I’d highlight a few points. Critiquing this passage is difficult because the writing is so unclear  – what, for instance, does the pronoun on “that function” refer to? I think what Adam (incorrectly) believes is that Tooby and Cosmides are using the term “solve problems” in the same way that the term is used in lay language, like “We don’t have any bloggers who know any biology; how are we going to solve that problem?” Of course, they have a quite different meaning in mind, as they indicate in the primer.

More broadly, Adam seems to think that Tooby and Cosmides are trying to explain why humans have brains at all, rather than brains that work the particular ways that they do. I think I’ll hold aside the bold claim that humans solve no unique problems, and I would love to engage the idea in last sentence in the paragraph if I could unpack anything meaningful in it. (Brain development diverged? From what? What’s subsequent benefits? The brain’s? A different path from what?)

I could go on, but I urge readers to have a look at the piece in its entirety. During this happy time of year, the holiday season, it’s all about joy, and there are a lot of laughs and giggles in there. I do want to engage one more confusion, which has to do with another key ingredient of evolutionary psychology, the computational theory of mind.

Responding to Tooby and Cosmides’ endorsement of the computational theory of mind, Adam writes:

The big problem here is in reducing the brain to a computer, which it isn’t.  While it might be a useful analogy within a very narrow context, it is simply foolish to define biology in terms of recent human technological developments (i.e. computers, machines, etc.).  This is simply unacceptable, in the same way that electrons are not like billiard balls, neither is the brain a computer.  In truth, there is nothing in the operation of a computer that could find an accurate comparison to the brain’s neurobiology (unless one is content to make the comparison simply because signals may be sent electrically).  However, by that logic, a television, telephone, and radio are all computers too.

As this quote illustrates, though again it’s hard to tell, he seems to be taking the commitment to the computational theory of mind to be a commitment to the details of a PC. Even more interesting is the dialog in the comments section of the blog in which a reader writes, “but my brain has neural networks with neurons having hugely complex dendritic trees and axon arbors and all they do is: compute!” In reply, Adam writes: “That is trivially obvious. It explains nothing”

So, on the one hand, the computational theory of mind is “simply unacceptable,” and on the other, it’s “trivially obvious.” (By the way, the fact that what the brain does is compute might seem obvious now, but it certainly wasn’t obvious (or trivial) before Turing and the other greats who ushered in the cognitive revolution.)

My guess is that the basic problem here is that Adam simply – again, to use his favorite term – doesn’t understand the computational theory of mind. (Gerhard: Pinker’s How the Mind Works is a good place to start. The book, though long, is made easier to work through by the Calvin and Hobbes cartoons sprinkled throughout. Fun!)

There are a number of other errors, and, again, readers of the blog will find much of the text amusing. I pause briefly to reflect on his closing remarks. He writes:

Without some insight that is nothing short of miraculous, there is no such thing as evolutionary psychology.  So for those that want to insist otherwise, here’s the criteria that must be met:

1.  Demonstrate that the behavior is neurologically specific enough to be predicted.
2.  Demonstrate that such behavior is heritable (Note:  Learning, by itself, is not sufficient).
3.  Demonstrate that such heritability actually is adaptive.

First, he doesn’t say what meeting these criteria is for – the list seems to be something about “the behavior,” but he was just talking about evolutionary psychology broadly –  so it’s hard to evaluate the claim. (He writes, just below these three, that “These requirements are difficult to meet for many aspects of biology, especially establishing that a trait is adaptive.” That “especially” bit in there implies that these criteria are not only for establishing this, but are for something else.)  One interpretation of this is that Adam is trying to articulate criteria to establish that a trait is an adaptation. However, heritability, as many have discussed – including biology textbooks –  is not a necessary criterion for showing adaptation; the eye is the usual example. (Gerhard: You might try to work through Williams’ Adaptation and Natural Selection. I’ve discussed this issue a number of times, including in a post, which refers to Futuyama’s textbook’s discussion of this issue.) (As a postscript, in a recent comment, Adam writes: “ I can’t imagine how something can be selected for and “evolutionary” and yet not be heritable.” This very basic error is quite revealing, given it’s widely known that selection tends to reduce or eliminate fitness-relevant heritable variation, yet in the same comment he writes “It’s little wonder that evolutionary psychologists don’t understand anything about evolution.” Ridley put it this way in his textbook: “Directional selection unambiguously should continue to alter a character until its heritability is zero” p. 250.)

Before closing, I want to address another criticism which has been surfacing occasionally, and it came up again in the context of my previous post about Campbell’s remarks. Geoffrey Miller made a comment on that post, to which Campbell replied in part that “regardless of what you [Miller] want to believe it [evolutionary psychology] should be[,] the people doing it are pretty terrible.” So, you know, we’re terrible. Campbell also specifically addressed my remarks in a comment, allowing that I made some “decent enough points,”  but he also claimed that “instead of acknowledging what everyone else can see as flaws and working to fix it, he [meaning me, RK] simply circles the wagons…” Obviously, I dispute that “everyone can see” the supposed flaws, and I certainly don’t know what his evidence is that I’m making no efforts to improve the field; perhaps he thinks that I should be reviewing papers, editing the field’s journals, writing blog entries about issues in the discipline, or something along those lines. I’m confident he wouldn’t have just claimed that I’m doing nothing to improve the field without any evidence.

In any case, this remark is an instance of a puzzling trope that goes like this: While evolutionary psychologists, for some strange reason, get all bent out of shape when bloggers call them “terrible,” “stupid,” “ridiculous,” and so on in public forums, and defend themselves, evolutionary psychologist do not, in contrast, “police themselves,” though this phrase seems curiously never to be carefully defined. The rhetorical strategy is to paint the discipline as self-congratulatory rather than self-critical.

From my perspective, I find this surpassingly odd – and by “odd” I mostly just mean dishonest – because there is substantial debate within the discipline. To take a just a few examples – and there are many to choose from –  consider the debate between Sperber and colleagues and Cosmides and colleagues on the cheater detection work; the various debates surrounding the function of friendship and morality, in which I myself have taken part; and West and colleagues’ (2011) recent sweeping critique of work on the evolution of cooperation in humans. Indeed, many papers I read or review take issue with one or more idea proposed by other evolutionary psychologists. And of course substantial debate occurs during the peer review process. My experience of the field is not that people are unwilling to engage and challenge their colleagues’ ideas. One particular arc of this narrative has it that Kanazawa’s work was critiqued only by people outside the discipline; this line of fiction might be useful to those with an axe to grind, but does a disservice to the substantial number of evolution-minded scholars who indeed engaged the work. Tom Dickins and Rebecca Sear are two such scholars, and there are a couple of dozen such papers.

Set against the backdrop of the tired and predictable (and false) accusations that evolutionary psychologists present no evidence for their claims, I find it interesting that, as far as I know, there are no data showing that the evolutionary psychology community is any less self-critical than any other scientific community. Absent such evidence, I take such accusations to be purely propaganda gambits made by people who are in fact insincere about the degree to which they care about claims requiring evidence to support them, interested only in disparaging a field they little understand, and (therefore?) seem to approach with emotion — “stupid,” “ridiculous,” “terrible” — rather than reason.

Ok, well, that was a bit saltier and lengthier than my usual remarks, and I’ll leave off here. Best wishes to all for the holiday and new year season. If you’re trying to figure out what to get Gerhard, please consider sending him one of the books I mentioned above. It would be, if I may, a blessing.

References

Dawkins, R. (1976). The selfish gene.Oxford:OxfordUniversity Press.

Dennett, D. (1995). Darwin‘s dangerous Idea: Evolution and the meanings of life. Allen Lane Press.

Pinker, S. (1997). How the mind works.New York: W. W. Norton.

Williams, G. C. (1966). Adaptation and natural selection. Princeton:PrincetonUniversity Press.

  • http://popsych.blogspot.com/ Jesse Marczyk

    I think, given his usage of “heritable”, Adam may intend the term to equate with “inherited”, as he writes:
    “Of course [having a stomach] is heritable. This suggests that you want to argue that genes that are conserved and fixed within a population are no longer “heritable”".

    • Robert Kurzban

      Yes, I think you’re right that he doesn’t understand the correct usage of this technical term. Their posts and subsequent comments suggest that they don’t really understand evolutionary biology (e.g., your remark about heritability) let alone evolutionary psychology, and, somewhat sadly, they don’t seem to have the least inclination to inform themselves. I find it sad, but not surprising. I confess I find it a bit strange that they are so confident in their condemnation of the field given their obvious confusions about it, but, again, I find this more sad than surprising

  • Gerhard Adam

    While you’re all chuckling, perhaps (just to take one example) you might defend the comments made in the primer to which I took exception in my comment about “design”.
    ——
    “But what did the actual designer of the human brain do, and why? Why do we find fruit sweet and dung disgusting? ”
    ——-
    I’d love to hear the scientific rigorous explanation for how these aren’t colloquial terms and how they mean something special in EP.

    • Robert Kurzban

      I think it’s great that you’re interested in learning about some of these ideas, and I’d be happy to send you a copy of the book if you’d like me to. A good place to start is pp. 68-72 (The Principle of the Accumulation of Design) in:

      Dennett, D. (1995). Darwin‘s dangerous Idea: Evolution and the meanings of life. Allen Lane Press.

      But the whole book illustrates how the term is used.

      Now, in the spirit of reciprocity, I have answered one of your questions, please answer one of mine. You claim in a comment that evolutionary psychology is not a field in which “there can be actual reproducible science,” comparing it to astrology. Why are the studies reported in, say, the most recent issue of Evolution and Human Behavior not able to be reproduced? If you want me to be more specific, I’ll take an example. Chudek et al. (“Prestige Biased Cultural Learning”) test some predictions from a model of prestige-biased transmission. Please explain the basis for the claim that work of this type is impossible to reproduce, and what, specifically, disqualifies it from being science.

      PS: If you’re feeling generous, please direct me for the evidence for your claim that “100% of the EP researchers who signed up to write wanted to do surveys about sex.” Knowing many EP researchers who don’t study mating, I found this surprising.

      • Gerhard Adam

        Sorry, but since I never made any of those comments, I can’t respond.

        • Robert Kurzban

          Ah, my apologies. My mistake. That was Hank’s comment, not yours.

      • Gerhard Adam

        BTW, you’ve simply side-stepped my question since Dennett doesn’t consider the “designer” as an entity that answers questions like “why”?

        In fact, if you follow Dennett, then you’d know that the concept of “design” places a major requirement on predecessor systems.

        “…the cheapest hypothesis will always be that the design is largely copied from earlier designs, which are copied from earlier designs, and so forth, so that the actual R-and-D innovation is minimized.”

        So, while you may argue that Dennett’s principle of “design” is what’s being expressed, it is difficult to imagine why the word “actual” was used in describing the “designer” unless something more anthropomorphic was being suggested. At its best, it is an extremely poor choice of language.

        • Robert Kurzban

          I haven’t sidestepped the question. The explanation is that they are referring to the process of natural selection. I don’t find the word “actual” there to carry the connotation you attribute to it, and I’d be surprised if others were confused in this way. I’m sorry you don’t like their word choice, but I hardly think this word makes the sentence an “embarrassment,” as you have it. (Your point about predecessor systems is irrelevant, so I won’t reply to it.) On the issue of disgust, the paper Josh suggested should help you out, and a video that I think will also help is, again, Dennett’s: [http://bit.ly/vLhd2V]. Watch the whole thing.

          As an aside, I think it’s very nice that you have acknowledged that you didn’t actually know what the term “heritability” meant and were using it wrong. Please consider that from our point of view, there is an irony in your assertions we don’t know any biology all while you were using this basic biological term incorrectly. I encourage you (and your co-blogger) to entertain the notion that many of the ideas that you disparage might be right, even if you don’t yet understand them, and that you still have a great deal of material to master in this area. I hope some of the sources I have directed you to help, and I’m happy to provide you more suggestions if you wish.

    • http://bettermovement.org Todd Hargrove

      Gerhard,

      I am unclear on your concern with the quoted sentence. You just said it was embarrassing and didn’t explain why.

      Is your concern that the sentence uses colloquial terms? Why is that a problem? Do you think that the meaning of “designer” is to be taken literally?

      In your blog post you seem to imply that humans don’t actually have a natural aversion to feces, and that any distaste for dung is a result of cultural influence. Do you really believe that?

      And do you think that EP cannot give us any good answers about why fruit tastes sweet?

      • Gerhard Adam

        My first problem is that this is supposed to be primer. So, if the intent is to introduce people to EP, it is an extremely poor choice of terms and concepts to introduce the idea of a “designer”. It’s not as if evolution isn’t controversial enough.

        “…you seem to imply that humans don’t actually have a natural aversion to feces”

        Once again, humans don’t, unless you want to qualify it as “human feces”. Unless you’re only used to city living, the majority of people don’t find it much of anything to get excited about. It used routinely as fuel or fertilizer, but “disgust”? That’s a personal value judgment. More to the point, it implies that there’s a disease relationship, despite having no evidence as to which diseases are spread through animal feces .. (some parasites, perhaps).

        As for fruit tasting “sweet” … that’s another value judgment. Define “sweet” beyond some arbitrary release of chemicals in the brain. What makes you think that this is anything uniquely human? If even animals without nervous systems might experience such a thing then doesn’t it seem peculiar to claim it as “psychology”?

  • http://bettermovement.org Todd Hargrove

    Gerhard,

    Ahh, so only humans raised in cities find dog shit disgusting. Got it.

    Fruit doesn’t cease to taste sweet because it’s a “value judgment”, or because the taste is caused by chemicals, or because the taste is not unique to humans. Those are complete non-sequiturs (and self-contradictory).

    You should do a study on that.

    • Gerhard Adam

      What’s disgusting? I have to clean stalls every day. Do you think dogs are the only animals on the planet? In any case, what’s so disgusting. You clean it up and move on.

      Put a plate of mealworms in front of you and then tell me what you find disgusting. Despite its nutritional value I suspect you’ll find your cultural inclinations dominating.

      My point about fruit, is that you can’t quantify what “sweet” means therefore the best you can claim is that many people enjoy it. Is that selected for? If so, show me. If you don’t know, that’s probably more likely.

      Moreover, why do you care if fruit is sweet? Are lemons sweet? How about tomatoes? What are you suggesting by talking about sweetness?

      • http://bettermovement.org Todd Hargrove

        Gerhard,

        If I can’t convince you that the sweetness of fruit and the stinkiness of poop have some basis in natural selection, then I can’t see the use of continuing this conversation. There’s a very good reason that fruit smells better than poop, and it’s not cultural.

        • Gerhard Adam

          You changed the argument. No disputes that fruit smells better, but to argue that this is something that was selected for makes no sense. The point was about something “disgusting”, not the aromatic qualities of the two.

          • Alex

            Why is it that fruit smells better if it wasn’t selected for? Do you think this is an intrinsic property of fruit? I guarantee there are a lot of species that would disagree that fruit smells yummy. Fruit smells yummy to us because people who had random mutations that guided them to find fruit yummy (i.e. be motivated to seek out said yummy fruit) did better than those who did not. Also, you do understand that Tooby and Cosmides do not think human beings are special in having psychology that is selected to solve specific problems. Every animal with a brain has it by virtue of that structure’s ability to solve an adaptive problem. The reason being that, like, brains are costly and natural selection tends to be frugal and therefore would eliminate a structure if it didn’t solve an adaptive problem. Hearts solve the adaptive problem of pumping blood, brains solve a suite of adaptive problems having to do with navigating and specifically reproducing in a complex world.

            Before you make the huge mistake of thinking I don’t understand by-products I will note that a by-product (or spandrel if you prefer pretentious architectural references) are always a by-product of some adaptation. Of course, noise (random variation) is also possible.

        • Gerhard Adam

          BTW, it seems that you want to use an evolutionary argument in discussing two completely opposing concepts (i.e. fruit & feces). Why not compare foods to see which are “disgusting”? Broccoli, mealworms, raw beef, steak, fried spiders, raw oysters, raw eggs, asparagus, chittlin’s. What’s the evolutionary argument for the diverse reactions to these foods?

          Bear in mind that many people would describe some of these as “disgusting”.

          • Josh

            Gerhard,

            This paper discusses feces quite a bit. You might find it of interest.

          • http://popsych.blogspot.com/ Jesse Marczyk

            Maybe I missed something somewhere; are you suggesting something along the lines that the only reason people prefer to eat fruits over feces is because their culture tells them to?

  • http://bettermovement.org Todd Hargrove

    Whoops. The last sentence in my previous comment shouldn’t be there. Please ignore.

  • Gerhard Adam

    “Why is it that fruit smells better if it wasn’t selected for? Do you think this is an intrinsic property of fruit?”

    …and this is why I will say that your argument is nonsense. Barbecue smells good too, was that selected for? Flowers smell good, what was the selection argument for that?

    You’ve simply taken a simplistic correlation and presumed a cause.

    “The reason being that, like, brains are costly and natural selection tends to be frugal and therefore would eliminate a structure if it didn’t solve an adaptive problem.”

    Natural selection tends to be NOTHING. To argue that it is frugal is, once again, a misplaced judgment. There is nothing that requires natural selection to eliminate a non-adaptive structure. “Cost” is only relevant if it impacts fitness.

    • Alex

      What is the alternative to the fact that certain things smell good because something was selected for? Note… it is complicated and learning are not answers. Even if one learned to like BBQ smell because of the association between it and eating delicious meat this would require specialized architecture for learning what smells to approach and avoid.

      I said “tends” since in general costly things that have no positive effects on fitness (i.e. reproductive success) are often eliminated from the gene pool (in the same way that traits that have a positive influence on fitness and no cost or a positive influence that outweighs a cost tends to spread in a gene pool until the trait reaches fixation). I apologize for using colloquial language in these descriptions but I’m afraid to use more biological jargon because you seem to be fundamentally confused about the basics.

      • Gerhard Adam

        I’m confused? Your assertion is little more than a “just so” story. Your notion about fruit smell being “selected for”, is absurd on the face of it. Where’s the evidence? You largely eat what you have been taught is food.

        Perhaps you need to do a bit more research.
        “When the large trays of foods, each in its separate dish, were placed before them at their first meals, there was not the faintest sign of “instinct” directed choice. On the contrary, their choices were apparently wholly random; they tried not only foods but chewed hopefully the clean spoon, dishes, the edge of the tray, or a piece of paper on it.”

        “From time immemorial adults as well as children have eaten castor oil beans, poisonous fish, toad stools and nightshade berries with fatal results. Against such error, only the transmission of racial experience as knowledge can protect. Such error affords additional proof that in omnivorous eaters there is no “instinct” pointing blindly to the “good” or “bad” in food.”
        http://www.ncbi.nlm.nih.gov/pmc/articles/PMC537465/pdf/canmedaj00208-0035.pdf

        Perhaps this will help clear up your confusion.

  • Marco DG

    Rob,
    I share the amusement, but I’m afraid that posts like this one only end up giving undue publicity to “science trolls” like Adam. It is one thing to respond to people like Myers, Coyne, Moran, Marcotte, etc., as they are highly visible on the Internet and/or have biological credentials. However, Science 2.0 is nothing of the sort – as far as I know, it is open to everyone’s rants and has no credibility at all. Why care?

    • Robert Kurzban

      Marco, you make an excellent point, and I struggled with this. I can’t really defend my decision. I can only say that I find the dishonesty aggravating, as I think you do, below, so I gave in to that a little bit. Second, as someone who values irony, I find their sputtering charges of biological ignorance very amusing in the context of their demonstrations of their own confusions. But, really, you’re right, and I concede the point. Not my best decision.

  • Marco DG

    The amount of dishonesty on display here is incredible. E.g., here is the paragraph quoted by Adam (above) in its original context (Davis, 1939):

    “Selective appetite is, primarily, the desire for
    foods that please by smelling or tasting good, and
    it would seem that in the absence of such sensory
    information, i.e., if one had never smelled or
    tasted a food, he could not know whether he
    liked or disliked it. Such proved to be the case
    with these infants. When the large trays of
    foods, each in its separate dish, were placed
    before them at their first meals, there was not the
    faintest sign of “instinct” directed choice. On
    the contrary, their choices were apparently
    wholly random; they tried not only foods but
    chewed hopefully the clean spoon, dishes, the
    edge of the tray, or a piece of paper on it. Their
    faces showed expressions of surprise, followed by
    pleasure, indifference or dislike.”

    For those who would like to learn more about the evolutionary psychology of taste preferences and disgust (including their development), the work of Paul Rozin is an excellent starting point.

  • Gerhard Adam

    Of course, it’s dishonest … which is precisely why I provided the link so that anyone could see the context.

    You people are unbelievable and are obviously incapable of exercising anything except your own confirmation bias.

    • http://popsych.blogspot.com/ Jesse Marczyk

      You largely eat what you have been taught is food…Such error affords additional proof that in omnivorous eaters there is no “instinct” pointing blindly to the “good” or “bad” in food.”

      So what you’re saying is that children can be taught that just about anything is food, yes? You would agree, for instance, that if we taught children that fruit is disgusting and feces is delicious, they’d agree and prefer to eat feces over fruit, correct?

    • Alex

      Yeah I am going to stop with this because you are clearly not engaging in an honest argument. I conceded above that clearly there is learning that goes on with what is appropriate and not appropriate to eat, but this is within a constrained space of all possible things one could eat. You again make the silly error of thinking that “learning” is an answer to the question of how something in the mind works. Not realizing this is a question: “Learning what? How is this learned rather than the billion other things that could have been learned? What features of the stimulus predispose someone to learn X rather than Y?”…I suppose you also think that fear can be similarly learned for any stimulus… I often hear Pinker being accused of arguing with a strawman in the blank slate but you hear this BS again and again.

      The explanation for fruit is not at all a just-so story… we can generate hypotheses about what properties of fruit make them taste sweet to us (i.e. what properties in fruit were selected so that we ate more of them and so caused us to survive better) these constraints and test these hypotheses in different contexts (things that taste sweet should have quality X). The evolutionary hypothesis is only useful is so far as it makes novel predictions. Here is an excellent paper on that this in relation to fatty acids. http://www.psych.ucsb.edu/~roney/other%20pdf%20readings/reserve%20readings/lassek%20and%20gaulin%202008.pdf

    • Marco DG

      Having provided a link does nothing to change the fact that you quoted that passage out of context, thereby distorting its meaning. In the complete paragraph, infants develop immediate positive/negative reactions to novel items after first tasting them, without any social reinforcement involved. You probably made the safe bet that nobody would actually follow the link and bother to locate the passage, but this is just my guess. Alternatively, you might simply have missed the meaning of the paragraph. I’m not sure which option is the most flattering.

      That said, I certainly don’t think a 1939 paper is the last word on taste preferences, and I’m only discussing it for the benefit of casual readers of this blog. This is my last post in this thread, as I’m not going to feed this hungry troll anymore.

  • Cdn

    Rob, this seems like a waste of your valuable time. Criticisms like this don’t merit a response.

Copyright 2011 Robert Kurzban, all rights reserved.

Opinions expressed in this blog do not reflect the opinions of the editorial staff of the journal.

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