Evolutionary Psychology

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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

Three New Books I Haven’t Read But Hope To

Published 10 April, 2012

My airplane reading recently has been Steve Pinker’s, The Better Angel’s of Our Nature. I have made it about two thirds of the way through, in part because I’ve had a few lengthy flights recently. It is, in my opinion, very good. One reason I like it is that it makes (even) me feel optimistic; if the murder rate keeps declining at the rate it has been, in 2035 it will actually be negative, meaning, I think, that previously dead people will come back to life, a possibility that seems appropriate for this time of year.

But this post is actually not about Pinker’s book, but instead about three books that I haven’t even started reading, but might be of interest to people who follow this blog.

The first is by E. O. Wilson, regarded by many as the grandfather of evolutionary psychology. The Social Conquest of Earth came out yesterday, accompanied by reviews in various outlets, including The New York Times and The Wall Street Journal (by Mike Gazzaniga, no less). According to the sources I’ve read online – and, again, the rest of this post is about books I haven’t actually read, and so I won’t try to review or evaluate –Wilson argues that group selection explains why humans are both so social and so successful. I can independently verify this by using Amazon’s feature which allows peeking in the book. At the beginning of Chapter 3, he writes,

Our bloody nature, it can now be argued in the context of modern biology, in ingrained because group-versus-group was a principal driving force that made us what we are. In prehistory, group selection lifted the hominids that became territorial carnivores to heights of solidarity, to genius, to enterprise (p. 62).

I suspect reviews and blog posts will be appearing with some frequency, with people chiming in on the book, pro and con, over the next few weeks. Indeed, Jerry Coyne has already written about it, including a remark about evolutionary psychology, with his not uncharacteristic remark that “[d]espite its occasional overreaching, the evolutionary study of human behavior has brought deep insights.  We are, after all, evolved mammals—it’s just that the fact we have culture, and that we can’t be experimentally manipulated, makes us hard to study.”

Speaking of group selection, the second book I thought I would mention is Jon Haidt’s, The Righteous Mind: Why Good People Are Divided by Politics and Religion. (I should probably admit that Jon was generous enough to ask me for some feedback on a draft of one of the chapters, and is giving me a free copy; full disclosure and all that.)

Still, I want to be clear that I haven’t read all of the book. From what I have read, and from having watched his TED talk, I feel comfortable saying that he, likeWilson, endorses group selection as an important force in human evolution. This isn’t necessarily his main project, as indicated by the title, which is trying to understand human political behavior. For this he relies in no small part on his Five Foundations model of morality (harm, fairness, ingroup, authority, purity), and the suggestion that people of different political persuasions lean more heavily on some foundations than others. (Liberals are big on harm and fairness, less excited about authority, ingroup, and purity. This extends even to their preferences for traits in dogs; watch at about the ten minute mark in the TED talk for what I think is a real highlight.)

Returning to the issue of group selection, which connects his book toWilson’s, he (Haidt) proposes (again, relying on Amazon; his italics):

…that human beings are conditional hive creatures. We have the ability (under special conditions) to transcend self-interest and lose ourselves (temporarily and ecstatically) in something larger than ourselves… (p. 223).

And, finally, out today is Jonathan Gottschall’s new book, The Storytelling Animal: How Stories Make Us Human. Again, I haven’t read it, but my sense from what I’ve seen about the book is that Gottschall’s thesis is that fiction is for simulating, allowing us to learn about the world, physical and social; fiction, according to this view, allows us to practice safely, an idea which seems perfectly plausible. I’m more generally pleased to see that some of our colleagues in the humanities –  Lisa Zunshine, Brian Boyd, Joseph Carroll, and so forth – continue to take evolutionary approaches seriously, and it seems to me that Darwinian Literature is doing well.

For my part, on this front, I continue to be interested in the observation that so many stories are moral, focusing on who has violated which rule, and what happens to them, coupled with the fact – is it a fact? – that young children seem to like to hear/read/watch the same story told over and over again, as if they’re learning the layout of the rules in the local moral landscape.

In any case, a few books you might want to check out to keep you occupied for those awkward times when the airplane door is closed but you’re still below 10,000 feet.


  • Chris Branch

    Hi Robert,

    As a mild spoiler for the Pinker book, when you get to the end you’ll see that he also has a discussion similar to the five foundations model of morality that you mention is covered in the Haidt book. Haven’t decided whether I should read that one yet.

    On an off-topic note, do you know if there’s any way to subscribe to this blog via RSS? The RSS link at left seems to only feed the journal articles and not the blog posts.


    Chris B

    • rkurzban

      Thanks for the comment. On your question, I sent a note to the technical person who works on this site, and I’ll post the answer as soon as I get it.

      • Chris Branch

        Sorry for the delay, forgot to check back… yes, it works, thanks!

  • Justin

    I would recommend Sam Harris’ new book Free Will. For those who use electronic readers it is around 2 or 3 dollars. I actually have read this book so not completely consistent with the theme.

    • Ian

      In a similar vein, check out Incognito by David Eagleman. Awesome discussion of free will and the legal system towards the end of it.

  • Ian

    Having read most of Better Angels of Our Nature and The Social Conquest of Earth, it seems to me that group selection is still somewhat of a simplistic explanation.

    Now, I have very little background in game theory, but common sense says that every day I invest a fair chunk of time and energy on group projects, that there’s some game theory at work. Simple stuff like showing up for work, cooperating with my colleagues, following laws, not stealing stuff, not engaging in nepotism or corruption, all takes place within a prisoner’s dilemma of morality, to use the most simplistic game-theory model. When I go out with friends, we’re generally quite cooperative too. No stealing one another’s girlfriends for instance. Game theory again.

    That kind of cooperation doesn’t need to be primarily genetic in origin. You can still have selfish genes and calculate that cooperation is in your best interests. You just need a whole lot of signalling and game theory to back that up, and ensure that everybody’s will work together.

    My hypothesis is that most of this signalling takes place using subconscious instincts, which then delivery the message to our consciousness of “trust him” or “don’t trust that guy” or “screw following the rules, I’m stealing those stationary supplies”.

    The fact that highly intelligent people tend to have fewer close friends (read: cooperative allies), whereas people who have the social skills to make lots of friends tend to only be moderately intelligent (ie non Nobel Prize winning) supports this argument. If the highly social people have game-theory cooperation algorithms taking up most of their brain-space, they probably don’t have enough left to form highly complex mental models of things like quantum physics.

    It’s been said that (social) fights in academia are so vicious because the stakes are so low, but perhaps it’s more because of the highly optimized nature of academic intelligence.

  • Doug Drake/Helian

    Wilson would obviously prefer to go out with a bang instead of a whimper. Here are a couple of quotes from his book on group selection:

    “For almost half a century, it has been popular among serious scientists seeking a naturalistic explanation for the origin of humanity, I among them, to invoke kin selection as a key dynamical force of human evolution… Unfortunately for this perception, the foundations of the general theory of inclusive fitness based on the assumptions of kin selection have crumbled, while evidence for it has grown equivocal at best. The beautiful theory never worked well anyway, and now it has collapsed.”


    “The selfish-gene approach may seem to be entirely reasonable. In fact, most evolutionary biologists had accepted it as a virtual dogma – at least until 2010. In that year Martin Nowak, Corina Tarnita, and I demonstrated that inclusive-fitness theory, often called kin selection theory, is both mathematically and biologically incorrect.”

    The last one looks like it’s aimed straight at Dawkins. Here are a couple more interesting passages:

    “Science grows in a manner not well appreciated by nonscientists: it is guided as much by peer approval as by the truth of its technical claims. Reputation is the silver and gold of scientific careers. Scientists could say, as did James Cagney upon receiving an Academy Award for lifetime achievement, ‘In this business you’re only as good as the other fellow thinks you are.’ But in the long term, a scientific reputation will endure or fall upon credit for authentic discoveries.”


    “Another principle that I believe can be justified by scientific evidence so far is that nobody is going to emigrate from this planet, not ever… The same cosmic myopia exists today a fortiori in the dreams of colonizing other star stystems. It is an especially dangerous delusion if we see emigration into space as a solution to be taken when we have used up this planet.”

    In a word, the old man has thrown down not just one gauntlet, but several. As for the general style, IMHO it’s as good or better than anything Wilson has done before. Age obviously hasn’t robbed him of his mastery of English. There’s a bit more of the pomposity of age when it comes to prescriptions for saving the planet, etc., but nothing too overbearing. All in all, the book is a remarkable achievement for a man going on 83 years old, whatever flavor of natural selection you happen to prefer.

    • Thom

      How can it be “a remarkable achievement” when it contains such passage as incoherent as those you’ve quoted about inclusive fitness? Those passages are simultaneously false*, confused**, and internally inconsistent*** – a triple whammy of nonsense.

      * “the foundations of the general theory of inclusive fitness based on the assumptions of kin selection have crumbled, while evidence for it has grown equivocal at best” – Just not true. See the various responses to the Nowak et al. paper, which point to many theoretical and empirical successes of inclusive fitness theory.

      ** Inclusive fitness is not a theory to be falsified or not; it’s a way of doing the accounting of natural selection. The ‘theory’ in ‘inclusive fitness theory’ is the mathematical usage of the term (my computer dictionary says “a collection of propositions to illustrate the principles of a subject”). This is different to the scientific usage (“a supposition or a system of ideas intended to explain something”).

      *** Compare “the general theory of inclusive fitness based on the assumptions of kin selection”, with “inclusive-fitness theory, often called kin selection theory”. Which is it: is inclusive fitness “based on” kin selection, or is it the same thing? Clue: neither.

      • Doug Drake/Helian

        Let’s just say it’s a “remarkable achievement” as a piece of literature. As far as group selection goes, I’ll be the first to admit that Wilson has gone way out on a limb. I had to smile when I read the book because of the fascinating history of the subject, though. It was like being surprised by an unexpected plot twist in a novel. V. C. Wynne-Edwards must be chuckling in his grave.

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

          I wonder how many times people need to say group selection doesn’t work before it really sinks in.

          Well, group selection doesn’t work: http://popsych.blogspot.com/2012/04/no-really-group-selection-doesnt-work.html

          • Doug Drake/Helian

            Wilson’s assertions that group selection accounts for our virtues and and kin selection accounts for our sins seems rather extreme, but so is the bald statement that group selection doesn’t work, period. The so-called “sophisticated” mathematical models that are claimed to decide the issue one way or the other strike me as a great deal cruder than the behavioral algorithms in an average video game. Is there any chance the evolutionary psychologists could seduce some hotshot young computationalist from the physics department into taking an interest in the matter? Then we might make some progress. At the moment, the whole controversy reminds me of the old debates about how many angels can dance on the head of a pin.

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

            Suggesting that a trait that actively hinders its own proliferation isn’t likely to spread doesn’t strike me as particularly extreme. No more extreme than suggesting a runner who breaks his own legs isn’t likely to win the race, in any case.

          • Thom

            Lets repeat the state of affairs, as briefly as possible:

            – Old-school group selection doesn’t work – i.e. it’s inconsistent with the theory of natural selection. Plenty of sophisticated models show this, and all the data say the same. Period. Even David Sloan Wilson would grant this, I suspect.
            – Multi-level selection theory and inclusive fitness theory are two ways of doing the accounting of natural selection. (This is why the ‘theory’ here is the mathematical use of the term.) Both work, and they can be translated into one another if necessary. The vast majority of evolutionary biologists prefer to use the terms and thinking of inclusive fitness, because it’s cleaner, and easier to think with. (Note: multi-level selection is not simple. It’s not the same thing as naive group selection.) See the West et al. paper in JEB, “How useful has group selection been?”.

            As for the comments that the models are “crude” – what?! This is Hamilton, Maynard Smith, Grafen, Frank (and others) you’re talking about – some of the giants of recent theoretical evolutionary biology. Note: saying that you didn’t have them in mind when you made the comment is no good. You said that the models offered in support of one line of argument were crude. These guys have developed those models. If you can show that the models are actually unconvincing after all, then you have a string of Science/Nature papers to look forward to. Note also that the massive empirical success of behavioural ecology in the last 30 years is based upon these models. So there’s theory and data there. Flippant remarks about angels on pins don’t cut it.

          • Doug Drake/Helian

            No doubt the Blank Slaters had oodles of papers in Science and Nature as well. It surprises me that people in the behavioral sciences have this sense of hubris, as if nothing like that could ever happen again.

            As for the models you refer to, they are indeed crude compared to, say, a modern radiation transport code or climate model. A comparable code designed to study group vs. individual selection might have tens of thousands of intelligent agents with a realistic pool of alleles, realistic patterns of reproduction, growth and behavior, inhabiting a realistic and dynamic environment. A full-up version of such a model would have literally billions of degrees of freedom, so some approximations would obviously be needed even with the fastest modern computers. Still, such a code is possible, and eventually something like it will be written. When that happens, it will likely cast more light and less heat on the subject of group selection than is presently the case.

      • Doug Drake/Helian

        I note in passing that David Buss refers to inclusive fitness as a “theory” in his popular textbook, “Evolutionary Psychology.” Is some rewriting in order?

        • Thom


          • Thom

            I should expand. If he says something like ‘the theory of inclusive fitness’, then yes, that’s lazy, and should be edited. The theory in question is natural selection. If he says ‘inclusive fitness theory’, that’s ok. I assumed from your question that he says something like the former.

          • Doug Drake/Helian

            Ah, then presumably the passage in question will pass your test of textbook exegesis. In fact, it refers to Wilson’s work. Here is the passage: “Sociobiology is not generally regarded as containing fundamentally new theoretical contributions to evolutionary theory. The bulk of its theoretical tools – such as inclusive fitness theory, parental investment theory, parent-offspring conflict theory, and reciprocal altruism theory – had already been developed by others.” I was unaware there was a significant difference between “the theory of inclusive fitness” and “inclusive fitness theory.” I’ll have to be careful how I parse my words in future.

  • Oliver

    Hi Rob,

    It seems to me that whenever these authors talk about group selection, what they really mean is “a tendency to form groups” (which is quite handy if you plan to engage in intergroup conflict), or even simply “cooperate”. Of course, a tendency to form groups (and compete successfully against other groups) has been a very important factor in human evolution, but it is not explained by citing “a tendency to form groups”, or by pointing to the benefits of doing so.

    It was for exactly this reason that all the other explanations of cooperation and groupishness were developed in the 60s and 70s. And it seems that “the tendency to form groups” — if not explained by kin selection, or reciprocity — is most parsimoniously explained by one of the other theories of cooperation, such as good old-fashioned mutualism (accelerated by the the theory of coalitions), without any need to invoke baroque models of ‘multilevel’ selection.

    So, when you get around to reading these books, I would be grateful if you would let me know whether I am wrong. Do any of these authors to use group selection as an independent causal force in the formation of groups (and not just use it as shorthand for the thing they want to explain, as an umbrella term for all the other theories of cooperation). After all, it is possible for them to do this. It is theoretically possible for a form of old-fashiooned group selection to kind of work; it’s just that, empirically, the right conditions seem vanishingly rare, and it is generally agreed that there no actual examples of it.

    Have Wilson and Haidt actually found some? I think we should be told.



Copyright 2012 Robert Kurzban, all rights reserved.

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