Group selection a done deal? Hint: no.

The modern theory of natural selection derives...

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In reading Jerry Coyne’s review of David Sloan Wilson‘s new book, The Neighborhood Project, I came across this succinct summary of what I agree is the current feeling on group selection:

Group selection isn’t widely accepted by evolutionists for several reasons. First, it’s not an efficient way to select for traits, like altruistic behavior, that are supposed to be detrimental to the individual but good for the group. Groups divide to form other groups much less often than organisms reproduce to form other organisms, so group selection for altruism would be unlikely to override the tendency of each group to quickly lose its altruists through natural selection favoring cheaters. Further, we simply have little evidence that selection on groups has promoted the evolution of any trait. Finally, other, more plausible evolutionary forces, like direct selection on individuals for reciprocal support, could have made us prosocial.

These reasons explain why only a few biologists, like Wilson and E. O. Wilson (no relation), advocate group selection as the evolutionary source of cooperation. […]

At least, this agrees with my reading of the literature;  I’m hardly an expert in this area, but I’ve been swayed by the writings of people like Coyne and the pair of Stuart West and Andy Gardner (e.g. this paper, if you can get it;  this video is also well worth watching).  And nothing D.S. Wilson has ever written has convinced me otherwise.  Thus, I was especially surprised when I picked up a free copy of New Scientist from the Ultimo Big Night of Science – which, incidentally, was fantastic –  and saw that they had published an 8-page hatchet job (which is behind a paywall online here) by Wilson in which he claimed that group selection (a.k.a. multi-level selection or MLS) “is firmly re-established” in evolutionary biology.    “Today, though,” he writes, “there is near-universal agreement among those familiar with the subject that the wholesale rejection of group selection was mistaken and that the so-called alternatives are nothing of the sort” (p. viii).

One of the biggest problems with group selection is that it’s mathematically equivalent to other, better explanations of evolution like kin selection.  Wilson knows this:  he rather transparently tries to co-opt the criticism in the paper by stating it as though it works in reverse (“In addition, it has become clear that the supposed alternatives for the evolution of prosocial behaviour are actually equivalent to group selection”).  In what I consider a despicable move, he even quote mines Andy Gardner:  “‘Everyone agrees that group selection occurs,’ stated evolutionary biologist Andy Gardner in 2008.”  But it’s instructive to look at what Andy Gardner actually said, in this 2008 Nature summary of the ‘debate’:

 “Everyone agrees that group selection occurs,” says Andy Gardner of the University of Edinburgh, UK. Yet Gardner and his colleagues Stuart West and Ashleigh Griffin have trenchantly criticized David Sloan Wilson’s arguments on this subject — a critique to which David Sloan Wilson responded by initiating a lengthy debate in the community under the heading ‘If the theorists cannot agree…’.

Wilson leaves off the part where Gardner and his colleagues don’t agree with him at all, which is a favourite tactics of creationists.  I’ll leave the implication of that up to the readers.

So if everyone agrees that the two are mathematically the same, why not use group selection?  I’ll highlight the strong argument made by West, Griffin, and Gardner which you can read here.  In responding to Wilson’s critique of an article that the authors wrote, West et al. point out three things (p.376):

  1. “No group selection model has ever been constructed where the same result cannot be found with kin selection theory.”
  2. “The group selection approach has proved to be less useful than the kin selection approach.”
  3. “The application of group selection theory has led to much confusion and time wasting.”

If you’re interested in this issue, I urge you to read the linked PDF and follow up with some of the references they give.  I don’t know of clearer writers on this subject, and it’s a great place to start.

I disagree with a lot of what D. S. Wilson writes, but I respect his right to hold the opinions and his efforts to prove his position right.  That’s how science progresses, and if he can ever come up with some strong evidence for his position (which I don’t believe that he has yet), I’ll take a good hard look at it and make up my mind anew.  Until then, though, I would take him much more seriously if he would stop with the claims that everyone agrees with him when they obviously don’t.

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2 thoughts on “Group selection a done deal? Hint: no.

  1. […] I’ll be the first to admit that I hold a dim view of multi-level selection, but I’d be really surprised if anyone in the MLS camp were to make […]

  2. […] such as altruism.  But (1) group selection reduces mathematically to inclusive fitness (follow the links in my previous post), and so (2) is trivially true.  Sure, it arose by “group selection”, but that’s […]

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