In recent years evolutionary theorists have been engaged in a protracted and bitter disagreement concerning how natural selection affects units such as genes, individuals, kin groups, and groups. Central to this debate has been whether selective pressures affecting group success can trump the selective pressures that confer advantage at the individual level. In short, there has been a debate about the utility of group selection, with noted theorist Steven Pinker calling the concept useless for the social sciences. We surveyed 175 evolutionary anthropologists to ascertain where they stood in the debate. We found that most were receptive to group selection, especially in the case of cultural group selection. The survey also revealed that liberals and conservatives, and males and females, all displayed significant differences of opinion concerning which selective forces were important in humanity’s prehistory. We conclude by interpreting these findings in the context of recent research in political psychology.Peter Turchin:
A particularly interesting recent study is the one by William Yaworsky, Mark Horowitz, and Kenneth Kickham, Gender and Politics among Anthropologists in the Units of Selection Debate, published a month ago in Biological Theory. It’s interesting because it addresses the question of group versus kin selection, which is of course one of the most dividing issues in evolutionary science.Related:Yaworsky and colleagues obtained 175 surveys from evolutionary anthropologists who served faculty in graduate programs in various universities (which means that they are training their own graduate students). Their analysis of the questionnaires showed that there were very striking differences between different groups of anthropologists. Liberals were much more likely to disagree with the statement that tribal conflict was a principal evolutionary force that shaped human behavior. Conservatives, on the other hand, thought that tribalism was a fundamental human trait. They also tended to agree with the notion that homicide was frequent in early human societies.
The differences between male and female evolutionary anthropologists were even stronger than between different parties. Women were very resistant to the ideas that tribal conflict was an important selective force and that homicide was common in prehistory. [. . .]
And I expect that the questions of the importance of between-group competition and the frequency of lethal violence in prehistory will eventually achieve the same level of consensus. It may take many decades, but my hunch is that it will happen more quickly than that.
In fact, it’s already happening. The data of Yaworsky and colleagues show that 80 percent of respondents disagree with Pinker’s assertion that group selection is a useless concept. A similar proportion thinks that group selection is an important process, and 55 percent consider group selection as a more important process than kin selection. In contrast, among the professors who trained this cohort of respondents, the previous generation, only 8 percent were strongly in favor or “leaned” towards group selection. We are winning!
5 comments:
It's important to note that the kind of group selection that most of these people are talking about is Cultural Group Selection (CGS). This is quite different from, e.g., the Hammond and Axelrod model, and other genetic-group selection models.
That includes Turchin: "there was a great degree of consensus among the participants that cultural group selection is the only general mechanism for explaining how human sociality evolved that really has the logical coherence and empirical support."
https://evolution-institute.org/blog/cultural-group-selection-in-phase-transition/?source=sef
The idea was mostly invented by Rob Boyd and Pete Richerson; check out their 1985 book if you want to see the origins. Joe Henrich is also an important figure. In short, the idea is that cultural group variation is much more easily maintained than genetic group variation. That's because immigrants can learn the local norms of the cultural group, but they can't change their genes. So while migration can quickly swamp genetic variation between neighboring groups, it may not do so as quickly for culturally transmitted things. Selection acts on variation, so this supports cultural group selection.
The variation has been measured, although not necessarily for cooperative traits: http://www.pnas.org/content/106/42/17671.full
It's important to note that the kind of group selection that most of these people are talking about is Cultural Group Selection (CGS). This is quite different from, e.g., the Hammond and Axelrod model, and other genetic-group selection models.
That includes Turchin: "there was a great degree of consensus among the participants that cultural group selection is the only general mechanism for explaining how human sociality evolved that really has the logical coherence and empirical support."
https://evolution-institute.org/blog/cultural-group-selection-in-phase-transition/?source=sef
The idea was mostly invented by Rob Boyd and Pete Richerson; check out their 1985 book if you want to see the origins. Joe Henrich is also an important figure. In short, the idea is that cultural group variation is much more easily maintained than genetic group variation. That's because immigrants can learn the local norms of the cultural group, but they can't change their genes. So while migration can quickly swamp genetic variation between neighboring groups, it may not do so as quickly for culturally transmitted things. Selection acts on variation, so this supports cultural group selection.
The variation has been measured, although not necessarily for cooperative traits: http://www.pnas.org/content/106/42/17671.full
RCB,
Despite being predominantly liberal anthropologists, the majority of survey respondents evidently come down in favor of genetic group selection as well. David Sloan Wilson:
"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. [. . .]
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.
"
https://evolution-institute.org/blog/the-tide-of-opinion-on-group-selection-has-turned/
And even people like Turchin and Henrich, who focus on culture, acknowledge the importance of genes or interactions between culture on genes. Human culture doesn't exist without human genes, and human genes have not been unaffected by human culture.
I don't see any mention of genetic group selection in that quote. But, sure - maybe they do think it's important.
It's true that genetic group selection and kin selection are just alternative mathematical approaches to the same general mechanism. In practice, though, genetic group selection usually refers to selection among large groups (villages, ethnicities, nations, etc.), whereas kin selection usually refers to small family groups and close relatives. Semantics aside, though, the fact is that large-scale kin/group genetic selection models, whether you write them in inclusive fitness notation or multi-level selection notation, just usually don't work under realistic assumptions - to my knowledge. (By "don't work", I mean that they tend not to select for altruistic traits among large groups - not that they are inherently incoherent.) So, that the mathematics of kin selection and group selection are equivalent does not imply that kin selection must suddenly work on enormous scales. (None of this is a critique of what you (n/a) have said; just venting.)
Cultural group selection, however, is mechanistically distinct from both, so that's a different matter.
Funny that many respondents recognized the mathematical equivalency of kin selection and group selection, and yet half of them still thought the latter was superior... What's going on there?
RCB,
I don't see any mention of genetic group selection in that quote.
Obviously referring to genetic selection: 'multilevel selection as superior to kin selection' / 'disagreed with the statement group selection misidentifies replicators and vehicles'.
Semantics aside, though, the fact is that large-scale kin/group genetic selection models, whether you write them in inclusive fitness notation or multi-level selection notation, just usually don't work under realistic assumptions - to my knowledge. (By "don't work", I mean that they tend not to select for altruistic traits among large groups - not that they are inherently incoherent.)
You keep repeating variations of this. I'm well aware many people claim or believe the same. I disagree.
Funny that many respondents recognized the mathematical equivalency of kin selection and group selection, and yet half of them still thought the latter was superior... What's going on there?
I haven't read the actual paper, but presumably for the same reason kin selection is a better framework for thinking about many questions in evolution than individual selection or gene selection (despite these all being mathematically equivalent). As mentioned in one of the quotes, it comes down to "which selective pressures in the environment matter, and what are their effects upon genes, individuals, genetic relatives, and groups"; and in the case of the evolution of human sociality a majority of respondents believe groups are important.
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