Several people on this website have raised the question of group selection, and asked me what I thought of it. The idea that selection operates on entire groups rather than individuals, and can lead to the evolution of group-level traits (altruism is supposed to be one of these), has been revived by several people. Among them are E. O. Wilson, but especially David Sloan Wilson, who has defended his notion of group selection in a fifteen-part (!) series on HuffPo, infelicitiously called “Truth and Reconciliation for Group Selection.”
I’ve avoided discussing this topic because it’s not my own area of research and it’s a thicket of contentious claims and counterclaims that often seem more semantic than biological. And I don’t have the mathematical expertise to appraise all the models. Nevertheless, the field seems to be converging on a solution (which is not without dissent!).
Fortunately, you can get an excellent summary of the state of the field in a little over an hour, thanks to the London Evolutionary Research Network, a consortium of researchers who hold regular meetings and debates. Last July, they held a very nice debate, “Is natural selection at the group level an important evolutionary force?” which is now available at Vimeo.
There were four speakers, each talking for around 20 minutes, and there’s a 70 minute question-and-comment session at the end. Here are the links to the separate videos.
Herbert Gintis (professor of economics, Santa Fe Institute, University of Siena, and Central European University)
Mark Pagel (professor of Biology, University of Reading)
Samir Okasha (professor of philosophy of science, University of Bristol)
Stuart West (professor of evolutionary biology, University of Oxford)
If you don’t have time for all of these, by all means watch Stuart West. I don’t know how he did it, but in 20 minutes he managed to sum up the whole debate, beginning with Darwin, moving through the group selection arguments of Wynne Edwards, and assessing modern D.S.-Wilsonian views of group selection. It’s a masterful performance.
And, as far as I can judge these things, West’s assessment is correct, and, I think, the one most smart people in that area are beginning to share:
1. The old idea of selection among groups leading to the evolution of group-level traits works only under very special circumstances.
2. The “new” view of group selection (NGS)—the one espoused by D. S. Wilson et al.—gives results that are either wrong or, when they’re right, essentially equivalent to those derived from the simpler and less confusing inclusive-fitness theory (IFT), pioneered by Price and Hamilton and developed in the 1980s. I’ll show Stuart’s slides:
3. NGS has not stimulated a productive research program. Virtually every advance in understanding the effects of group-level dynamics on the evolution of social behavior has come from IFT instead. Here West checks off which of the two theories has better helped us understand various biological phenomena (in the slide below, “GS” is group selection and “IF” is inclusive fitness theory). It’s a slam dunk for IF.
West concludes that while NGS is not usually wrong, it’s not useful, and, anyway, it’s not really new, since its mathematics were already worked out several decades ago. While advocates of NGS claim that they’re ignored (and, at worst, persecuted), West implies that the theory is simply irrelevant. His conclusion:
Watch all the speakers if you can, for the 80-minute debate is a painless way to educate yourself on the issues. And kudos to the London Evolutionary Research Network for holding this and selecting a great panel of speakers. Let’s see more of these—I’d like one on species concepts and speciation!