Science is not a popularity contest. A fact such as “continents drift” is true regardless of whether it is heretical or universally accepted. Nevertheless, it’s gratifying to know that science is enough of a truth-finding process that facts once branded as heretical can become widely accepted with time.
A survey of evolutionary anthropologists on the subject of group selection1 provides evidence that the tide of opinion has turned on that once heretical subject. William Yaworsky, Mark Horowitz, and Kenneth Kickham surveyed 175 evolutionary anthropologists (including biological/physical anthropologists and behavioral ecologists) from departments with graduate programs. The respondents spanned the range from assistant to full professors, and 28.7% were women. The authors also assessed political orientation; 74.5% of the respondents identified as liberal. Although women and conservatives were in the minority, they were sufficiently represented in the sample to test for differences in attitudes toward group selection.
The results of the survey demonstrate a big generational effect. When asked to assess their own training as graduate students around the best explanation for human sociality, 57.5% reported that their mentors were “strongly” or “leaning” toward kin selection, 34.2% of their mentors were “neutral,” and 8.2% were “strongly” or “leaning” toward group selection. Among the respondents themselves, 55% regarded multilevel selection as superior to kin selection as an explanation of human sociality. 80.7% disagreed with the statement that group selection misidentifies replicators and vehicles. 64.9% disagreed with the statement that group selection has no utility. 78.7% agreed that cultural group selection is important.
Critics of group selection sometimes accuse proponents of wishful thinking—of wanting to see the world through rose-colored glasses (even though a proper of understanding of between-group selection is anything but rosy!). The results of the survey demonstrate statistically significant effects of gender and political orientation, although in a complicated way. Liberals were more likely to prefer multilevel selection as an explanation but were less likely to regard tribal conflict as a principle selective force. It seems that liberals and conservatives and men and women differed most on matters such as the frequency of homicide, tribalism, and tribal conflict, which in turn influenced their views on group selection vs. kin selection. Liberals and conservatives did not differ in their belief in the possibility of an egalitarian future or genuine altruism.
An important development in the history of thinking on kin and group selection is called equivalence—the possibility that the two theories do not invoke different causal processes and are inter-translatable, thereby deserving to co-exist rather than one replacing the other. This is in contrast to the original formulation of kin selection by both W.D. Hamilton and John Maynard Smith as a theory that does not invoke group selection. Hamilton’s reformulation of his theory in terms of the Price equation, which he published in 1975,2 marked the beginning of awareness about equivalence. It is gratifying that most evolutionary anthropologists have absorbed its meaning. Yaworsky et al. state:
Again and again in our survey respondents took the time to point out that mathematically, kin selection and group selection amount to the same thing. Instead, they are in disagreement about ontology: that is, which selective pressures in the environment matter, and what are their effects upon genes, individuals, genetic relatives, and groups.
In addition to their survey, Yaworsky et al. present a nice synopsis of the group selection controversy and the polemics of the current “debate.” One thing that stands out is that most of the evolutionary scientists known and revered by the general public, including Richard Dawkins, Steven Pinker, and Jerry Coyne as critics of group selection and E.O. Wilson and Martin Nowak as proponents, are out-of-touch with their own scientific discipline—as represented by the survey results. I include Wilson and Nowak for their failure to absorb the concept of equivalence by continuing to treat kin selection vs. group selection in an either/or fashion. The posturing and hyperbole of these major figures (sample: Pinker calls group selection a “scientific dust bunny” that “has no useful role to play in psychology or social science”) does not reflect well upon them, compared to the more reasoned attitude of the average evolutionary anthropologist.
This year marks the 40th anniversary of my first article on group selection3—and I entered the field when most experts had declared the controversy already over! As one illustrious professor counseled a graduate student in the 1980’s, “There are three ideas that you do not invoke in biology—Lamarkism, the phlogiston theory, and group selection.”4 It’s gratifying to see hard evidence that the tide of opinion on group selection has turned, at least among evolutionary anthropologists in departments with graduate programs. I would like to end this post by relating the survey results to some of my own recent writing on the subject.
In my article Richard Dawkins, Edward O. Wilson, and the Consensus of the Many in This View of Life, I pointed out that these two icons are out of touch with their own field of evolutionary biology in their failure to absorb the concept of equivalence. I based my argument on dozens of scientists who publish on the subject and might have a preference for one theory over the other but at least recognize their equivalence. The nearly 150 scientists who co-signed a letter criticizing the article by Nowak et al. in Nature (see my TVOL article for details) were complaining about Nowak et al.’s failure to recognize the legitimacy of inclusive fitness theory, not their use of group selection as their own preferred framework. It’s nice to know from the survey that the average evolutionary anthropologist is in tune with the current scientific literature, the polemics of Wilson and Dawkins notwithstanding.
In Mopping Up Final Opposition to Group Selection, I explained the concept of equivalence with the following story:
Imagine that Joan is talking to Bob and makes a statement based on certain definitions. Bob gets upset and blurts ‘Well, that’s not true according to my definitions!’ That is a stupid move on Bob’s part, which puts an end to productive communication. Of course any given statement depends on the definitions underlying the statement. Productive communication requires Bob to evaluate Joan’s statement according to her definitions and then translate her statement into an equivalent statement according to his definitions, like translating a statement from one language to another.
It’s nice to know through the survey that the average evolutionary anthropologist doesn’t act like Bob on the topic of group selection. Now if only our most prominent public spokesmen for evolution would just follow suit.
In Challenge to Kin Selectionists: Explain This! I first affirm the concept of equivalence and then raise the interesting possibility that two theoretical frameworks can be equivalent in some but not all respects. I then present three major examples (equilibrium selection, community-level selection, and human cultural evolution) that can be straightforwardly understood in terms of multilevel selection but not kin selection theory—or so I claim. My challenge to kin selectionists is friendly and I will be delighted to be proven wrong.
In my newest book, Does Altruism Exist? Culture, Genes, and the Welfare of Others, I say that the group selection controversy is over. Just as with previous controversies that took decades to resolve, such as the controversy over continental drift, people will look back and wonder what all the fuss was about. This enables me to provide what I call a “post-resolution” account of how altruism evolves—one that anyone can understand. I also devote an entire chapter to the concept of equivalence. Again, my assessment that the group selection controversy is over is based on the published literature. It’s hard to find a recent article on kin selection or group selection in the recent, peer-reviewed literature that doesn’t acknowledge the concept of equivalence. It’s gratifying to know that the message has been received by the average evolutionary anthropologist.
Science is a truth-finding process, but as the philosopher Thomas Kuhn pointed out with his concept of paradigms,5 scientists can take a long time to arrive at the facts of the matter, taking many twists and turns along the way. The acceptance of group selection has all the earmarks of a paradigm shift. Decades were required and some illustrious scientists have chosen to go down with their ships rather than change their minds. The average evolutionary anthropologist in a department with a graduate program has made the transition, but the general public receives such mixed signals on the topic of group selection that it is impossible to know what to think. Hopefully, the survey by Yaworsky et al. will be followed by others and the consensus about group selection among the experts can begin to be shared with the general public.
- Yaworsky, W., Horowitz, M., & Kickham, K. (2014). Gender and Politics Among Anthropologists in the Units of Selection Debate. Biological Theory. http://doi.org/10.1007/s13752-014-0196-5
- Hamilton, W. D. (1975). Innate social aptitudes in man, an approach from evolutionary genetics. In R. Fox (Ed.), Biosocial anthropology (pp. 133–155). London: Malaby Press.
- Wilson, D. S. (1975). A theory of group selection. Proceedings of the National Academy of Sciences, 72, 143–146.
- Recounted on p. 40 of Sober, E., & Wilson, D. S. (1998). Unto Others: The Evolution and Psychology of Unselfish Behavior. Cambridge, MA: Harvard University Press.
- Kuhn, T. S. (1970). The structure of scientific revolutions (2nd ed.). Chicago : University of Chicago Press.