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Cultural Evolution

“Cultural evolution” names two different things. In nineteenth-century anthropology it meant the passage of societies through stages, the unfolding sense; since the 1980s it has meant, for most of the people who use it, the change of culturally transmitted traits in populations, the descent sense. The field that uses it in the second way agrees that culture evolves and disagrees, in the words of the Stanford Encyclopedia of Philosophy’s entry by Tim Lewens and Andrew Buskell, about “precisely how theories of cultural evolution should be fashioned, and how they should be related to more traditional understandings of organic evolution.”

Dual inheritance

The programme began with population models. Luigi Luca Cavalli-Sforza and Marcus Feldman’s Cultural Transmission and Evolution (1981) treated cultural traits as passed from parents, from other members of the parents’ generation and from peers, with each route changing a trait’s frequency in its own way. Robert Boyd and Peter Richerson’s Culture and the Evolutionary Process (1985) added the forces that make cultural change differ from genetic change: learners adopt a variant for its content, copy the most common behaviour (conformist bias), or copy the successful, and individuals modify what they have learned before passing it on, so that what is acquired in a lifetime is inherited, the feature traced under Lamarck. The result is dual inheritance: genes and culture as two systems of inheritance that interact. The programme’s main lines, its textbook cases and Joseph Henrich’s account of cumulative culture are set out under Cultural extensions of Darwinism.

Memetics

Richard Dawkins’s meme (1976) proposed the other route: a cultural replicator, copied from brain to brain as a gene is copied from body to body, with culture explained from the meme’s point of view. The idea drew wide attention and a journal, but did not establish itself as a research programme. Memetics did not establish itself; Bruce Edmonds (2005) argued that it had failed because the gene–meme analogy added no explanatory or predictive power beyond what was available without it. The dual-inheritance theorists kept the population thinking and, in Henrich, Boyd and Richerson’s “Five Misunderstandings about Cultural Evolution” (Human Nature, 2008), rejected the claim that cumulative, adaptive cultural evolution needs replicators at all.

Cultural attraction

Dan Sperber’s Explaining Culture (1996) argued that ideas are rarely copied; they are reconstructed in each mind from partial evidence, and reconstruction transforms them. What keeps culture stable despite this is that transformations are not random: they tend toward certain forms, attractors, set by human psychology and the environment. On this account much of the stability that selection is invoked to explain comes from the bias of transformation itself. Nicolas Claidière, Thom Scott-Phillips and Sperber posed the question directly in “How Darwinian Is Cultural Evolution?” (2014), answering that selection among variants is one factor in cultural change and attraction another, and that the balance between them varies case by case.

Cultural group selection

The most ambitious use of the apparatus is at the level of groups. Boyd, Richerson and Henrich have argued that because conformist transmission keeps groups culturally distinct, groups can compete, and those whose norms produce more cooperation grow, spread or are copied, so that selection among groups explains the scale of human cooperation between non-relatives. Richerson and colleagues set out the evidence in Behavioral and Brain Sciences (2016), under the title “Cultural Group Selection Plays an Essential Role in Explaining Human Cooperation”. Peter Turchin’s Ultrasociety carried the argument to the scale of states and empires, with warfare between societies as the selective force. The critics come from several directions. Steven Pinker’s “The False Allure of Group Selection” (2012) argued that the idea is used loosely, and that where it is made precise it either reduces to ordinary individual-level processes or fails to hold; philosophers including Kim Sterelny and Jonathan Birch have pressed on how the mechanism is to be specified and tested.

Placement

In the space Peter Godfrey-Smith built for grading Darwinian populations, culture sits toward the marginal side: transmission is low in fidelity, and in human societies success often depends on position rather than on the intrinsic character of a variant. The grading itself is on the criterion page. The objection that the whole framework misdescribes culture, from Joseph Fracchia and Richard Lewontin and from Tim Ingold, is set out with the older stage theories in Deep time and evolution.