Friday, 6 February 2015

David Sloane Wilson has doubts; asks for help

People have been trying for decades to find something that group selection predicts that kin selection does not. Now the results are in. The most coherent forms of group selection make no new predictions. They are an alternative accounting technique that makes the same set of predictions that kin selection makes. This is fairly widely acknowledged by most of the parties involved these days. Of course, kin selection has been part of the standard orthodoxy in biology for decades.

However, it seems that David Sloane Wilson still has doubts about this. He doesn't see how to apply kin selection in some cases - and he's publicly asking for help. As far as I can see, David has nothing. One of his three examples is cultural group selection. I replied here.

I'm not sure how much help David will get from other kin selection enthusiasts. Most have been unimpressed with David's attempts to rechristen and take credit for a well-established existing theory. Group selection has a long association with junk science. Kin selection depends on close relatedness to produce adaptations. If you emphasize group membership instead of close relatedness - you include a bunch of cases where there's no close relatedness, and adaptations are not produced. Group selection was pushed by kin selection into the scientific fringes - where it focused on cases not obviously explicable by kin selection - which were mostly cases where the theory didn't actually work. In short, group selection is kin selection's evil twin.

David engages in a bit of a straw man attack on kin selection in his article. He focuses on Hamilton's rule. Hamilton's rule is one of the findings by kin selection theorists - but it isn't the same thing as kin selection. Here's how Hamilton explained the topic:

The existence of altruism in nature can be explained by thinking about the replication of genes. We need to descend to the level of the gene, rather than the individual, in order to see that the gene exists surrounded by copies of identical genes that exist in all its relatives - in particular in its close relatives, its siblings, who have a half chance of carrying a copy of that particular gene, its offspring, which also have a half chance, parents: a half-chance, cousins: one eighth, etc. Seeing this swarm of genes that exists around a particular one, we can then ask what is the behavior caused by this gene that is most likely to cause the propagation of this set of copies in the relatives around it.
That is more like kin selection in a nutshell. Of course, these days, we have to clarify that it's the evolutionary gene that we mean here. Hamilton's rule is the product of kin selection and a bunch of assumptions.

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