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Group selection is dead; get over it!

It is the sort of thing that people like, and want, to believe. Thus, though better theories supplant it in scientific usage, we may be certain that the 'hypothesis' will persist for a while as an element of folk-science. Eventually, that remnant, too, may vanish in light of discordant facts, and the essential imagery of this once-scientific hypothesis will recede to a revered position in the popular environmental ethic, where it doubtless will do much good.

PZ Meyers suggests that David Sloan Wilson has "made a persuasive case for group selection (but then [he admits], I'm already partial to the idea anyway). " This partiality is surprisingly common, despite the lack of empirical evidence that group selection (as opposed to kin selection) is of more than negligible importance as an evolutionary force in natural ecosystems.

Theory, too, suggests that group selection can be ignored. We've known since the 1970's that the conditions under which group selection can counter individual selection almost never occur, namely: ("deme sizes of less than 25... and migration, could not be too much greater than five percent per generation" Levin BR, Kilmer WL. 1974. Interdemic selection and the evolution of altruism: A computer simulation study. Evolution 28: 527-545).

It's not that group selection can't work. For example, Muir (Poultry Sci 75: 447) increased egg production by selecting for the collective egg production of groups of 4 hens (4<25, no migration!), with reduced aggression a side effect of human-imposed group selection. But in nature, a bird whose selfish behavior leads to decimation of its flock just switches to another flock. In nature, there's no human in charge to impose selection at the group level, limit group size to <25, and prevent migration between groups.

Kin selection theory generates lots of experimentally verified predictions every year; group selection none (under nonartificial conditions). But people want to believe in it because it makes them feel good. Sound familiar? Group selectionism is a religion. (The quotation above is from Goodman's 1975 paper "The theory of diversity-stability relationships in ecology", but seemed equally applicable to group selection.)

I know it's risky to disagree with the awesome PZ, but his flame-throwing tank is no match for the 6.7-meter walls of Fort Denison.


How did language/speech evolve if not by group selection? It's hard to see how it could confer an advantage to a single individual.

You could imagine a planet where groups of nonrelatives somehow kept numbers below 25 and prevented migration. On that hypothetical planet, group selection could be important. Here on earth, however, the groups that developed language were probably composed of kin, so kin selection would have been important. See last entry for a quantitive treatment of kin selection based on Hamilton's equation. Once the rudiments of language developed, there would have been individual selection for speaking persuasively, in acquiring mates, getting others to risk their lives "for the tribe" and so on.

Group selection dead? Au contraire.

You should read this article in New Scientist by DSW and EO Wilson:


The only field study they cite is on cooperation among lionesses, who are typically close relatives, often sisters. Cooperation among relatives is readily explained by kin selection. If anyone publishes a paper with field data that can be explained by group selection better than by kin selection, I will be glad to review it, but I'm not holding my breath.

If you read my post, you'll see I'm not denying that human-imposed group selection can work under controlled conditions. I'm only saying we don't have good examples of group selection in nature strong enough to reverse individual and kin selection. So, if group selection is never strong enough to change the outcome of anything in nature, we can ignore it.

David Sloan Wilson's flagship for group selection is an experiment performed on bacteriophages in 96-well plates. Still, he makes far-fetched claims about group selection shaping human evolution. [insult deleted]

Your distinction between "human-imposed" and "natural" forces is arbitrary. Human-imposed forces are natural. Group selection is the only explanation for how humans have been able to colonize every continent on earth. It's why we have healtcare and governments and morals.

I agree that selection we impose inadvertently (e.g., by plowing fields) isn't any different in principle from natural selection.
By "human-imposed selection", in this post, I meant "human-designed group selection." This can be very effective when it includes human-imposed barriers that prevent individuals (hens, say) from switching groups. Are there groups of humans that almost never exchange members with other groups? How are they doing?


Group selection the ONLY explanation for governments, for health care, for morals? HA! What about synergistic and by-product mutualism + kin selection + costly signaling + punishment + coercion + bargaining + reciprocity + reputation management + social norms to coordinate action in games with Pareto-efficient equilibria? Are you implying that because people pay taxes to support the payment of other people's health care that they are being altruistic, and that legislators are altruistic for passing budgets that pay for poor people's health care? Ridiculous. I see absolutely no reason why the things I list could not produce large-scale cooperation. And if you really stop and think about what "large-scale cooperation" really entails, you very quickly see how mutualism and coercion are the most parsimonious explanations. And as for small-scale cooperation, you very quickly see that it mainly occurs, by definition, in small groups often composed of kin. And small-group cooperation among non-kin is not difficult to explain because it often occurs between kin and rarely occurs one-shot interactions.

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