The two Wilsons on sociobiology

Blogging on Peer-Reviewed ResearchIt's not often I get to comment on as-yet-unpublished work, but I have been sent a copy of a forthcoming essay by David Sloan Wilson and Edward O. Wilson, two giants of the theoretical evolutionary field, defending and redefining the nature of sociobiology (Wilson and Wilson 2007). As I have recently (i.e., in the last five years) come to be an unflinching sociobiologist, I think it is worthwhile summarising their argument and making some comments. This is the first in a rambling series riffing on that paper.

Introduction

Back in the dark ages, when I was a masters student, Kim Sterelny gave a series of lectures on sociobiology, which (in the late 80s) was very much out of favour at the time. One comment he made has stuck with me since: "Something like this has to be right, but what?" Evolution made us what we are, that much cannot be gainsaid. The question is, what are we? What is it that evolution has made us?

Since those mysterious and dark days, evolutionary psychology has come, and to some extent, waned, and there have been a series of new discussions on group and multilevel selection. Wilson and Wilson raise the question: what does this all mean for sociobiology?

Now I want to note at the outset that there are several kinds of thing that get called sociobiology, according to one's attitude to biological accounts of social behaviour, and the age in which the writers under consideration worked. Few disciplines are as history-ridden as evolutionary biology, and few within that as social biology. I mark out three types of social biology: the standard Evil Demon of eugenics and "social Darwinism" (which is neither social, nor Darwinian, nor ever an actual historical movement, but that's for another day). We may dismiss this as being of no positive value apart from an object lesson in how not to apply science to society. The second is the movement of the 1970s to treat humans as social animals and discuss the ways in which evolution has shaped us. This is the sense of the term in Wilson and Wilson, and which I will discuss below. The third is that same evolutionary psychology. A few short words about that before we begin.

Evolutionary psychology has two major flaws in my opinion. One is that it is almost always adaptationist even when no evidence of adaptiveness is available. Adaptation is, as G. C. Williams noted of group selection explanations, an onerous hypothesis, to be supported or not used. It is too easy to come up with "possible scenarios", let alone possible adaptations. Such explanations need to follow the evidence rather than use, as EvPsych does, a priori arguments from the self-evident truth of natural selection and the nature of evolution.

The second major flaw relates to this. On the (a priori) assumption that selection always favours modularity, EvPsychologists claim that most of the human behavioural repertoire and its underlying neurology is modular. Each module is, as the literature has it, "informationally encapsulated and domain specific", which roughly means that it does one thing well and only that thing, without hints from the rest of our cognitive and sensorimotor system.

I think that the modularity hypothesis is not a priori true. Evolution may favour independence of organic traits, but there's a bit of a confirmation error here - we tend to identify things that are independently able to evolve because they have done so, not because they have to be modular. In fact, it seems to me that evolution doesn't favour modularity - at some levels everything is pleiotropic. For example, it is turning out that individual genes are implicated in many different traits at an alarming rate (basically, as soon as we go looking, so we find it to be), and conversely no trait realistically exists that is not the effect of many genes, usually activated or inhibited by small RNAi fragments.

What is true at the molecular level seems also to be true at the developmental level. While there clearly are developmental modules, it is not clear (to me at any rate) that evolution favours modularity for all traits. Many traits are the outcome of many developmental stages and locations. And of all our organs, the brain surely is one that is most distributedly affected by a series of developmental influences. So if that assumption fails, the underlying justification for the Massive Modularity Hypothesis falls down too. There may be some modules in our cognitive development, jsut as there are some in our sensorimotor system. But we have to find them before we can discuss them. All of the evidence from lesions, rapid inference and processing, and the like, seem to me (as I noted before) to be explicable as non-modular subsystems that are not isolated from the rest of cognition.

So the sense of "sociobiology", and the broader term "social biology", which includes ethology (the science of animal behaviour, including ours), that I want to address is what E. O. Wilson originally meant by it: evolved inherited behavioural repertoires that are the result of, or are constrained by, selection.

So, in the next post, I will present the two Wilsons' position, and then discuss it, with a view to convincing you all of my opinion (of course).

[You can tell I have finished teaching, can't you?]

Wilson, David Sloan, and Edward O. Wilson. 2007. Rethinking the theoretical foundation of sociobiology. The Quarterly Review of Biology 82 (4):327-348.

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Anyone want to explain the "adaptationist" debate in layman's terms? I've seen this before as a criticism of ev-psych but I don't fully understand it.

So what happened to Wilson and Wilson (and I don't mean the Beach Boys). Did they join Ala A'Dale waiting for their intro to end?

Is the criticism of Ev Psych as being adaptionist one a criticism of the subject, the way is it being approached now, or just of the worst bits of the area (i.e. the bits that get into the papers)?

There must be adaptionist stories to be told (once one's got past the introduction, of course), but I wonder if there is a fundamental problem in that we don't know enough about the ecology and society of our ancestors when the adaptation was happening.

Bob

Very timely for me, as I'm currently reading The Blank Slate. I am aware of the EvPsych controversy of course, but not knowledgable enough to tell when Pinker is on solid ground, and when he is straying into less well-supported claims.

Eamon:

I think Pinker's Blank Slate is obviously biased in the telling of the history of the sociobiology debate ... all proponents of it were reasonable and motivated solely by scientific truth and all opponents were ideological hacks ... in his telling. Besides the unlikeliness of such a tale, it doesn't match more neutral tellings, such as Ullica Segerstrale's Defenders of the Truth. The fact is neither side exactly wrapped themselves in glory.

If he can't be objective about that, can he be trusted about the weight of the evidence? It's only in the last third of the book or so that he discusses specific evidence and some of the arguments are persuasive but do the specifics bear the weight of the larger theory? I'm not expert enough to tell but I have my doubts.

Also timely for me as I'm reading Mary Midgley's Evolution as a Religion, in which she gives sociobiologists what for.

I'm curious about the way you've set this up, John, because sociobiology was accused of being adaptationist before evol psych really hit the seen. Indeed, Gould and Lewontin's "Spandrels" paper is largely directed at sociobiology. I always thought that evol psych was supposed to be the more sensible version of sociobiology (less adaptationist, and less tied to explaining our sexist and racist biases) -- although it has never seemed much different to me. But I haven't read the Wilson and Wilson, so maybe sociobiology is being reborn? (again?) Anyway, I'm interested to see your next post.

Yes, there is a sense in which EvPsych is an outgrowth of sociobiology of the 70s. And yes, it was often adaptationist in the 70s. But it need not be, and my approach is to take phylogenetics as the basis for it, not adaptation.

There is also the ever-present danger that we will provide culturally biased (e.g., racist or sexist) cultural behaviours as being biological. That's another reason to use phylogenetics as the test. Chimps and other apes don't tend to be so tied up in western or patriarchal biases (although observers can be), which is why I'm such a de Waal booster.

So I will stake out territory for not-necessarily adaptationist sociobiology, in which adaptation requires positive evidence of selection rather than being the foundation for it. That is not necessarily Wilson and Wilson's view, though...

It's probably important to distinguish "evolutionary psychology" from "Evolutionary Psychology" (note capital letters), which is a convention that a few folks have used lately. The former refers to a field in which scientists, mostly biological anthropologists and human behavioral ecologists, use evolutionary principles to study current human behaviors. This approach is exemplified by people like Robin Dunbar, Eric Alden Smith, Kim Hill, etc. The latter approach is Evolutionary Psychology sensu stricto, in which the proponents have an (almost dogmatic) adherence to certain guiding principles, namely that 1) are brain is modular, 2) almost all of our current behaviors need to be explained with reference to the environment of evolutionary adaptedness (i.e., that us humans spent much of our evolutionary history as hunter-gatherers and thus are designed to solve hunter-gatherer-type problems), and 3) that natural selection is responsible for the majority of our behaviors but since selection acted on our "stone age" minds, there's not always an immediate fitness-benefit to our behaviors. This approach is exemplified by John Tooby, Leda Cosmides, David Buss, Steven Pinker, and others.

The former folks, such as Dunbar, tend to approach human behavior from a behavioral ecology background and use optimality models and ethnographic data in order to develop an understanding of the evolutionary forces that may, or may not, guide current human behaviors.

The latter folks, such as Buss, are more trained as psychologists and tend to use functional-adaptive inference as a means to understand human behaviors.

To me, the former camp adheres to a "current utility" notion of adaptation (since any behavior that can be causally linked to a fitness gain is evidence of current selection), and the latter camp uses an "etiological" notion of adaptation (since they are concerned with the adaptive problems faced by our ancestors back in the savanna, and not what types of selection we experience today). These latter folks, frankly, are also much better at marketing themselves to the public since they are very compelling writers.

Of course I meant, "...1) our brain is modular..."

By Rich Lawler (not verified) on 18 Nov 2007 #permalink

Rich Lawler's distinction between human behavioral ecology / Darwinian anthropology and evolutionary psychology (in the strict sense - the Tooby & Cosmides school) is accurate. Dual inheritance and related niche construction are also distinct schools. Then there are evolutionary developmental psychologists like Chisholm and Worthman. Finally, the neo-Jensenists who use evolutionary ecology concepts and jargon (e.g. the deplorable work of Rushton). All of these often conflicting approaches get thrown together into the generic category of "evolutionary psychology."

The most adaptationist approach? DS Wilson's multilevel selectionism, which is tantamount to multilevel adapationism. According to DS Wilson, various cultural practices including religion, dance, music and art - which some view as epiphenomenal (or in the case of religion from some perspectives, a parasitic meme or a maladaptive susceptibility) - are likely group-level adaptations. Historically, social organicism is a highly functionalist approach. In contrast, from a strictly individual agency perspective there is no reason why at the collective level societies cannot be riddled with conflict along various dimensions, suboptimal compromises and miscommunication, and maladaptive practices. (See Edgerton's book Sick Societies.)

DS Wilson is not entirely wrong. But just because organisms were once groups (of cooperating individual cells) does not mean that all social groups are necessarily incipient superorganisms.

The sort of thinking that says, "How might it have been in our ancestors' interests, as individuals, or in the 'interests' of their genes, to behave in the enviroment of the ancient savannas?" seems to me to be perfectly reasonable as long as its constraints are recognised.

I don't see why our ancestors couldn't have had certain evolved behavioural propensities just as much as lions do, or chimpanzees, or any other social animal you care to name. Some of those propensities might be expressed only in certain environments, but others might be well-buffered, in the sense that they might be expressed a wide range of accessible and survivable environments.

Whether or not anything like this was/is actually the case is an empirical question, but I see nothing wrong with pointing out that it's a coherent possibility, as sociobiologists and evolutionary psychologists have been doing for the past three decades. Nor is there anything wrong with acknowledging that novel hypotheses, drawn from such assumptions, could sometimes have explanatory power or even be correct.

The problem as I see it is a bit different. At least some advocates of the above picture may think that they can reach conclusions about human nature by a piori reasoning based on what "must" have been adaptive in the EEA. I'm not sure that I've seen anyone reputable make such a mistake, but it's an obvious temptation, and I've certainly seen it made by people outside of the field who want to apply evolutionary thinking to their own research program, e.g. in the social sciences.

The trouble is that a whole range of possible behaviours might have been adaptive back then, for all we know. If we threw sexual selection into the mix, we could probably dream up all sorts of bizarre possibilities.

While we can hypothesise away, we can't go back in time to observe how evolving humans actually did behave in the ansestral environment. Even if, like lions and chimps and whatever, we have certain evolved behavioural propensities that are now significantly buffered against environmental influences, we will have to test hypotheses about them in various other ways, some of which may be quite indirect and inconclusive.

That doesn't make evolutionary thinking useless. It just means that its use is limited. It may offer us an additional source of hypotheses about human nature, which is good, but they are still only hypotheses, and there could be many conflicting ones. They will still need to be tested by the ordinary methods of social, etc., psychology - if they can be tested effectively at all.

When they have their wits about them, evolutionary psychologists seem to acknowledge all of this. They'll say, rightly, that evolutionary psychology is just psychology with evolutionary thinking thrown in as a source of new, otherwise-unintuitive or otherwise-inaccessible, hypotheses. But that leads me to the conclusion that few if any such hypotheses have yet been tested satisfactorily. We can all have hunches, but there is nothing like a body of well-corroborated theory.

My own hunch is that evolutionary psychology can and will illuminate human nature, but I don't think it is yet on a properly scientific basis. It's still more like philosophical speculation about limited and ambiguous data.

That's not a terrible thing - the heliocentric theory was once philosophical speculation, too. But it's a serious limitation if we think evolutionary psychology can actually be applied in some way. I think it's currently very dangerous to rely on any "conclusions" that any sociobiologists or evolutionary psychologists think they have established.

Since this is being brought up. Does anyone know if there are any good blog reads relating to evolutionary psychology/sociobiology based on the article that came out in PNAS a couple weeks ago entitled "Phylogenetic analyses of behavior support existence of culture among wild chimpanzees" by S.J. Lycett et al.?

Link to article:
http://www.pnas.org/cgi/content/abstract/104/45/17588?ijkey=22b4bfde206…

commentary on article:
http://www.pnas.org/cgi/content/full/104/45/17559

Catshark writes: I think Pinker's Blank Slate is obviously biased in the telling of the history of the sociobiology debate ... all proponents of it were reasonable and motivated solely by scientific truth and all opponents were ideological hacks ... in his telling.

What you said. I'm past that section, and yeah: even without the background to rebut his claims specifically, I found his whole account suspiciously one-sided. I can't believe Gould, Lewontin, et al are really that stupid.

So I will stake out territory for not-necessarily adaptationist sociobiology, in which adaptation requires positive evidence of selection rather than being the foundation for it. That is not necessarily Wilson and Wilson's view, though...

Sounds interesting!

(Everyone, please ignore my egregious spelling error above. I can't believe I wrote "seen" instead of "scene"!)

I once wrote a post in "Principles of Neurobiotaxis" on EvPsych. However, by now I realise that what was missed in it was a more philosophical analysis: one important problem (but far from being the main problem) of EvPsych is that it incurs in category mistakes, choosing as its categories of analysis stuff which does not really exist - hence the modularity hypothesis.
I do not understand the extent in which this also happens in sociobiology - I only read "popular accounts" of it. However, I'm going to read Wilson and Wilson right now, and see what can I extract from it. Thanks for the enlightening post, mate!

"Everyone, please ignore my egregious spelling error above. I can't believe I wrote "seen" instead of "scene"!"

It was less egregious than the ever-popular "tenants of the faith" and less fun than "bare with me"!

Russell, by "EEA" do you mean to indicate "early environment of our ancestors"?

Hi Salient,

By "EEA" Russel means "environment of evolutionary adaptedness", the idea that almost all of our modern day behaviors are adapted to a Pleistocene way of life, a period roughly corresponding to 2 million to 10,000 years ago. That is, a period in which our hominin ancestors roamed around as hunter-gatherers prior to the emergence of agriculture. It's a fairly formalized concept, promulgated by John Bowlby, Leda Cosmides, John Tooby, and Donald Symons, among others. By formalizing the EEA concept in this way, this has naturally attracted some scrutiny, notably by David Buller in his (at times devastating) book-length critique of Evolutionary Psychology, "Adapting Minds."

In fact, it seems to me that evolution doesn't favour modularity - at some levels everything is pleiotropic.

Can you explain why modularity and pleiotropy are mutually exclusive?

Just because a given phenotypic trait may be the result of the expression of a number of different genes, why would that necessarily argue against the large-scale reuse of that trait? Do you consider hair/scales/feathers, to take one example, as modules?

Derek, I'm not saying that evolution doesn't employ modularity. Of course it does. Nor is pleitropy necessarily exclusive of modularity. But the question is whether it must favour it. Pleiotropy indicates that if modules arise they do so at no particular level. So if multiple roles at one level result in a module, well and good, but there's no guarantee that a particular level will result in modules ipso facto.

The brain clearly is modular - not only do we have evidence of sensorimotor modularity, the entire brain is composed of modules: neurons. But that doesn't imply that neurons will be implicated necessarily in a behavioural module.

I'm a bit puzzled by your last sentence, John. Irrespective of the evolutionary aetiology (adaptive, spandrelish, or whatever), doesn't it seem that neurons must be involved in any behavioural modules that do exist?

Lions don't like water and won't go swimming. Tigers are swimmers. Ligers turn out to be more like tigers in that respect, but more like lions in others. If these different behaviours don't causally supervene on something in the different species-typical neurological structures of these morphologically-similar animals ... well, what's the alternative?

It's also difficult to see any conclusion under than that the different genotypes of these similar cats somehow systematically build their brains to guide their behaviour in different ways. The genes involved are doubtless pleiotropic, and the phenotypical characteristics concerned massively polygenic, but all the same ...

What am I not understanding here?

Thanks Rich and Russell.

Doesn't 2 million to 10,000 years ago seem a little recent to postulate about the origin of some of our behaviors? We diverged from our common ancestor with chimps about 6 million years ago (give or take quite a bit), and yet we seem to have some behavioral characteristics of chimps (including murder) and some with bonobos (particularly bonding through sexuality). Yes, I know that bonobos split from the chimp ancestor after we split from our common ancestor with chimps, but this could suggest that the common ancestor was both aggressive and sexual.

For example, the fact that chimpanzees react sexually to little red bottoms fits with the known ability of human males to react much more readily than human females to visual sexual stimuli. Perhaps it would be more accurate to say that human females place less emphasis than do males on visual cues in mate selection.

I suppose that such conjecture would be too early for ev-psych, though perhaps it would not be too early for sociobiological hypothesizing.

I do follow the reasoning concerning the potential problems with both systems of theorizing, but I have always thought that multidisciplinary approaches are probably optimal. In a sense, when you critique both ev-psych and sociobiology from the vantage point of your separate disciplines, that sort of insight could inform research approaches in the critiqued discipline.

Salient, Richard might know better than I how much specific theorists or groups of theorists lock themselves into a specific time period that is supposed to be relevant enough to count as the EEA. I was thinking about it fairly loosely, and as far as I can see you have a good point.

... and, John, I think I simply misunderstood your sentence. I think I get it now, but clarificatory comment or other response to my comment would still be welcomed, because I see some potential ambiguity in what you're saying.

I will be presenting my views in post 5. They are remarkably like Salient's (nice blog, by the way. I subscribed). To tease you all, I would say that sociobiology begins, and most of the hard work is done, in identifying those traits that we share or diverge from with our closest relatives.

Russell, I merely mean that massive pleiotropy of genes suggests that phenotypic, and in particular behavioural, modules are in fact not likely outcomes, if selection is held to act on genes. There will be some modularity, but if a gene is tightly constrained in its functional role for other purposes, it is not decoupled enough to be used in an independently evolving module elsewhere. This would tend to limit rather than require modularity.

The EEA is a fictional construct. There never was a particular environment to which our behavioural repertoire needed to evolve rapidfire responses. In fact, I think we are in our wild state now, as we always have been. We construct our environments, both in social terms and ecological terms, and we adapt always to these.

As Mephistopheles might have said, why this is our natural environment, nor are we out of it.

Hi Salient,

Yes, you raise a good point. One that has certainly be raised in response to the formalized EEA concept. If you consider the EEA, it suggests that the adaptive traits we possess were the adaptive solutions solved by our ancestors. But if you think about this, what about the EEA of our ancestors? They would also have their own EEA, corresponding to a period in which their adaptively successful predecessors lived...and so on. This has been noted by a few folks. Rob Foley (bioanthropologist at Cambridge) has a paper on this, noting that many of our adaptive behavioral traits evolved at different times and are shared by ever more inclusive clades of primates. I believe Foley's paper is published in the journal "Evolutionary Anthropology" in 1995.

And yes, as John notes, the EEA is not a place, but rather a statistical composite of selection pressures that acted on the human lineage roughly during the period of 2mya to 10kya.

I'm not defending the EEA concept (it is both useful and inconsistent), just relating my understanding of it.

P.S. And the reason some proponents of the EEA use 2mya to 10kya is that 2mya (roughly) corresponds to the emergence of the genus Homo, and in particular Homo habilis. The 10kya portion corresponds to the emergence of agriculture and sedentism. Given some recent analyses suggesting that "H. habilis" is probably better viewed as an australopithecine (i.e., "A. habilis"), the EEA proponents might want to shift their beginning period forward to about 1.6mya, corresponding to the emergence of Homo erectus/ergaster. But again, trying to delineate a particular period in the past where we expect most of our adaptive behaviors to have been forged seems a bit over zealous.

My saying that 2mya to 10kya seemed a little recent was not a criticism of your points, it was more a question about the EEA concept. Thanks for the clarifications. This is obviously an interesting area that should be added to my to-read list.

I confess to being confused about the connection between pleiotropy and modularity of brain function. Perhaps I don't quite understand the concepts. Is it not the case that pleiotropic genes are more likely code for enzymes and signalling molecules rather than for structural molecules? Such genes would seem more likely to be associated with regulation of development rather than with construction. I understand modularity to describe the dedicated, functionally semi-isolated functions of some types of neural networks (visual 'construction' rather than visual association, for example).

Are you saying that pleiotropy functions against the development of structurally dedicated modules? Would the development of modularity, or even of multifunctionality, not rely upon pleiotropic (and epigenetic) versatility? If you don't wish to waste your time educating the ignorant, a couple of urls would be welcome. Thanks.