Cultural evolution

Cultural evolution is the change in learned information and practices across generations, rather than change transmitted through genes. Its significance lies both in its speed and in the explanatory challenge it poses: language, song, science, and customs can develop through copying and variation, while the diversity of human cultures cannot be reduced to genetic inheritance alone. The concept extends an evolutionary way of thinking beyond genes without treating cultural transmission as biologically identical to genetic reproduction.

Cultural transmission and speed

Cultural transmission is conservative in that information is passed onward, yet it can also generate evolution. The contrast with genetic change is visible in language: Geoffrey Chaucer could not converse with a modern English speaker, although an unbroken chain of roughly twenty generations connects them, with each person able to speak to the next. Language changes through transmission between people, and its rate is described as orders of magnitude faster than genetic evolution.

This distinction makes culture more than a secondary expression of biological inheritance. Dress and diet, ceremonies and customs, art and architecture, engineering and technology all change over historical time. Their development resembles speeded-up genetic evolution, though it is not genetic evolution. Cultural change may also be progressive: modern science is described as better than ancient science, not merely different, because understanding of the universe can improve over time. That improvement is placed in a historical sequence, with its current burst beginning in the Renaissance after a long period in which European scientific culture remained at the level reached by the Greeks. The comparison does not imply that genetic evolution is always steady; it too may proceed in brief spurts separated by stable plateaux.

Saddleback song as a model

The saddleback, a bird living on islands off New Zealand, supplies a non-human example of cultural transmission. P. F. Jenkins described an island repertoire of about nine distinct songs. Individual males sang one or a few, and neighbouring males could be grouped into dialects: one set of eight males with adjacent territories, for example, shared a particular song called the CC song. Some dialect groups shared more than one song.

Comparison of fathers’ and sons’ songs showed that these patterns were not genetically inherited. Young males were likely to acquire songs by imitating territorial neighbours, in a process analogous to learning a human language. For much of Jenkins’s observation, the island’s song pool remained fixed, with each young male drawing a small repertoire from it. Yet transmission could also introduce change. A mistake in imitating an existing song sometimes produced a new form; changes could involve pitch, repetition, elision, or combinations of parts of other songs. Some innovations were abrupt, remained stable for years, and were copied accurately by younger recruits, forming a recognizable group of singers. Jenkins called these origins of new songs cultural mutations. The example shows both continuity and variation: a shared repertoire persists, but copying can produce a new form that itself becomes transmissible.

Birdsong and examples of cultural evolution in monkeys are presented as illuminating but limited cases. Human culture displays the process on a much broader scale, extending across many kinds of learned practice and changing within historical time. The saddleback example therefore serves not as an equivalent to the full range of human culture, but as a clear demonstration that transmission without genetic inheritance can still yield patterned change.

Analogy, natural selection, and its limits

The analogy between cultural and genetic evolution had often been noted, sometimes with mystical overtones the account rejects. The comparison is also applied to scientific progress: Karl Popper is identified as a particularly illuminating guide to the relation between scientific development and evolution by natural selection. The discussion points as well to work being explored by L. L. Cavalli-Sforza, F. T. Cloak, and J. M. Cullen. These comparisons make evolutionary analysis available for culture, but they do not erase the difference between cultural and genetic transmission.

That difference matters when explaining human behaviour. Accounts framed in terms of biological advantage have treated tribal religion, for instance, as a way to solidify group identity in a cooperative, pack-hunting species. Such explanations can be restated in terms of gene selection rather than group selection. Humans may have lived for much of the last several million years in small kin groups, and kin selection or selection favouring reciprocal altruism may have contributed to basic psychological tendencies. But these possibilities do not explain the formidable range of cultural forms or the differences among societies. The contrast between the utter selfishness attributed to the Ik of Uganda in Colin Turnbull’s account and the gentle altruism attributed to Margaret Mead’s Arapesh makes that explanatory gap vivid. The argument therefore calls for beginning again from first principles: for understanding the evolution of modern humanity, the gene cannot remain the sole basis of evolutionary thought. It enters the account of culture as an analogy, not as a complete explanation.

Replicators and cultural change

The wider framework helps clarify both the force and the limit of evolutionary language. Genes cooperate in developing bodies: a survival machine contains thousands of genes whose effects interact, and a body is a temporary combination reshaped by sexual reproduction. Crossing over further complicates any image of genes as neat, self-contained units, since chromosome material can be exchanged within the sequences that code for proteins. A gene is therefore defined for the argument as chromosomal material that can persist through enough generations to act as a unit of natural selection, rather than simply as one discrete coding segment.

This account also cautions against treating a phrase such as “gene for altruistic behaviour” as a claim that one gene single-handedly builds a complex trait. Genes influence nervous-system development and behaviour, but development is an interlocking process involving other genes and the environment. The honeybee hygiene study provides a concrete model of how inherited differences can contribute to a complex behaviour: hygienic workers locate diseased grubs, uncap their cells, remove the larvae, and discard them. In Rothenbuhler’s crosses, first-generation hybrid hives did not show the complete behaviour; later groups displayed complete hygiene, none, or only uncapping. Removing caps by hand revealed that some apparently non-hygienic bees could perform the removal step. The example concerns genetic inheritance, not cultural evolution, but it sharpens the distinction: a learned cultural tradition is transmitted by imitation, whereas the bee behaviour described is investigated through inherited differences and their interaction.

Evolutionary language also requires care because it can make replicators sound purposeful. A gene does not consciously seek descendants; the shorthand means that genes with effects tending to increase their representation are more likely to persist. Likewise, purpose-language applied to memes or other cultural replicators is metaphorical, not evidence of conscious intention. The broader principle is that natural selection favours replicators through differential persistence and propagation. Cultural evolution draws insight from that logic, while its distinct route of transmission—learning across minds rather than copying through genetic inheritance—remains essential to the explanation.