What’s wrong with evolutionary explanations of human behavior (as commonly understood)

The evolutionary side of human behavior is something which is always good for heated discussions, having strong implications for important social issues. And often enough, people criticizing the evolutionary perspective find themselves in the trap of being seemingly unscientific. This, I believe, is a symptom of how the prevailing positivist („objectivist“) understanding of science is narrowing the scientific discourse, and the public discourse about science. But „political correctness“ is not the only way to oppose these (pseudo)evolutionary arguments.

I liked watching the first few classes of Robert Sapolsky’s „Human Behavioral Evolution“ course at Stanford from 2010, which are available for free on iTunes U (yes, you need iTunes). Even though the pointedness and entertainment of his arguments can be a little too much for a European audience, I highly recommend it for everybody who wants to fill in gaps in his or her understanding of evolution. And for people who consider themselves solid on the basics, I recommend a 20-minute summary of the criticism of evolutionary biology, at least as it is perceived and used by the public. I’m talking about the last 20 minutes, starting at 1:14, of the lecture 3 — Behavioral Evolution II (April 2, 2010). Here is a brief summary:

Sapolsky argues that evolutionary theories are criticized in three basic assumptions that they rest on, which he calls:

  • Heritability (of behavioral traits)
  • Adaptiveness (of every feature of organisms)
  • Gradualism (of the evolutionary process)

The main problem with the heritability assumption is, of course, that things are very muddy on the actual genetic/molecular level if you try to point to genes that are causal to certain behavioral trends. But (as I would add) this could be dismissed as a temporary problem, waiting for advances in the science involved. Nobody doubts the general role of the brain in causing our behavior just because our knowledge of the brain regions and processes involved is still very rudimentary.

Much more important to me, then, is the critique of the adaptiveness assumption. It has been argued (and Sapolsky himself is mostly convinced, as am I) that many observable features of organisms (including many behavioral features) are merely „spandrels“ (from architecture as „space between arches“), meaning they are there only as unavoidable by-products of something that evolution is really about. This has, for instance, been famously shown for the evolution of human chins as a by-product of our „shortened muzzle“, after interesting theories on the adaptive value of chins had been put forward. And that leads to another important critique of the adaptiveness arguments: They are mostly what Sapolsky calls „Just-So-Story-Contests“ — finding the most convincing story to explain why something is (and has to be) the way it is.

What was really new to me was the argument against the assumed gradual way in which evolution takes place, and which is the foundation of the famous idea that small advantages pay off over time. Actually, there is evidence pointing towards a more stepwise evolution, long phases of relative stability interrupted by short, drastic episodes of change, a theory called „punctuated equilibrium“. As a result, the element of constant competition which feature so centrally in our „narrative of evolution“ has to be revised, with its importance reduced drastically. And that’s quite a revolution, especially to the layperson’s perception of (social) evolution.

And I’m very happy that in this context he even discusses the political side of evolutionary theories of (human) behavior. Coincidentally, the dominant model of evolution, focussed on constant competition, was put forward by a number of white southern (US) male researchers, while the challenges and modifications come from researchers from the more politically liberal North-East of the US, called „Marxist“ by Sapolsky. And he mentions sociobiologists form the former Soviet Union who have developed models of evolution more focussed on the interaction with difficult external living conditions rather than the competition within a species, called „abiotic selection“. Whoever wants to claim that science is just progressing on its path of objective truth, with random imperfections that will be smoothed out over time, good luck :)

The range of social issues he mentions which are justified as „natural“ through the dominant understanding of evolution is broad, from male domination to social hierarchies, aggression and sexual coercion.

I am very impressed that somebody who so obviously enjoys looking at human behavior through the evolution glasses sides on most points with the critics who argue for keeping the researchers own interests, world-view and ideology in mind, and who modify the dominant image of evolution in ways that very much change the implications for our (human) social life that are commonly drawn. And I’m very curious how he will live up to that standard in the classes to come.

Datum: Mittwoch, 1. Juni 2011 18:10
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3 Kommentare

  1. 1

    Standard evolutionary explanations do sometimes sound a bit like a coherent tale that is not compelling though. Those three points you made serve as a good grid to sort counter arguments. On gradual evolution I’d like to add, that social scientists discussed evolutionary lock-ins in this respect: How can we achieve a better set of social rules (e.g. norms, conventions, formal rules…), if there is no gradual way to reach them by a trial and error process of singular rules? Does this mean that we need a simultaneous (and coordinated?) change of rules in certain situations? This hints at the fitness of „evolutionary laws“ themselves (thus we may not get rid of a meta-principle like „fitness“, but concrete adaptation processes may not be rigid over time) — heredity may prove to be more successfull by use of non-gradual randomization of traits.
    Anyways, I think it is important to keep in mind the purpose of evolutionary models. They serve to answer specific scientific questions. Political correctness to my mind means not to confuse different questions: Why is my chin formed the way it is vs. What am I „supposed“ to do on this planet?

  2. 2

    Lieber Roberto!

    Danke für Deine Gedanken.

    I very much agree concerning keeping the purpose of evolutionary theory in mind, even though I think it can (!) be fruitful to bring it into other fields, just like almost always bringing concepts from other lines of thinking in is a „creativity technique“.

    I don’t quite understand why social science should have to deal with this „lock in“ problem at all. Aren’t social change processes in general thought to be driven by finality (as opposed to causality) — they occur for something as opposed to because of something, and can naturally occur in big lumps — large laws or sets of laws passed together like our upcoming Energy Turn? Or are you referring to more abstract, less formalized norms? Even there, because of the meaning-making process they are part of, I would argue that broad, related changes can quite easily occur together, take the 60s with their famous cultural revolution spanning art, teaching, family values, politics, etc.

    A remark concerning „we may not get rid of a meta-principle like ‚fitness‘“: of course we need principles concerning utility, desirability, fitness/„fit“ (in the sense of being appropriate for a specific circumstance, much different from the general implications it has usually taken on!), maybe „correctness“. But the question is which word will be best used for this concept in different concepts, and borrowing the biologically colored concept in social science and even epistemology invites a host of undesired connotations, so we maybe better look for another word. And I think the change of meaning and discussion will not even be very subtle. Like substitution „useful“ for „right“ when talking about theories…

    And: Interesting definition of political correctness! Mine (ad hoc) would be: Speaking (writing, etc.) in a way that is aware of the way words and concepts shape how we experience the world and how we will be inclined to work for change in the world — much in line with what I wrote above about the fitness of theories, a wording I would never use (even though I like fit).

  3. 3

    (1) Mutations that cause something to be neutral are extremely, extremely rare. So is the probability for spandrels, because, over several thousand generations, tiny advantages or disadvantages on fitness matter.
    That doesn’t mean spandrels don’t exist, but usually they are connected to an adapation (belly button is a very good example, I think).
    Keller&Miller (2005 or 06 or 07) have a good paper about schizophrenia and genetics, which is very good when it comes to paying attention to these details.

    (2) Just so stories: totally. And one major advance was Williams&Nesse, 1994, why we get sick. The question is not „Why is Depression an adaptation“, the question is „Why did evolution leave us vulnerable to depression“).
    There is a good youtube video about that with Dawkins & Nesse.

    But: just-so stories have nothing to do with the field itself. Just because people write bad papers about gravity doesn’t make gravity inexistent ;)
    (3) Stepwise vs gradual: it is not very smart to think in these categories. There is no reason to assume that this is an EITHER OR question. Because it is not. Antibiotics resistance in bacteria is a good example. Would that be stepwise or gradual? Hard to say, by definition of these words. Both mechanisms clearly exist, and we know that. 
    (4) „Whoever wants to claim that science is just progressing on its path of objective truth, with random imperfections that will be smoothed out over time, good luck„
    Not random, we have systematic errors, the biggest one being the human being itself with all its biases. Still, we do smooth out things over time.
    (5) „The range of social issues he mentions which are justified as „natural“ through the dominant understanding of evolution is broad, from male domination to social hierarchies, aggression and sexual coercion.„
    Nobody with a brain does that. I want to see quotes here, from leading researchers in the field. Because I don’t know a single one. When Thornhille&co published their book about rape being an adaptation, they wrote a couple of introductory pages about how this is NOT a moral judgement, how this does NOT mean that it is ok to rape etc.
    Newspapers, women’s rights organisation etc just ignored this chapter of the book completely and summarized: Thornhille says rape is good.
    (6) ta-ta, E.