Unfortunately, these shoots failed to materialise into an evolutionary science of culture. Instead, a different kind of evolutionary theory became popular in the late 1800s. This alternative theory drew more from Herbert Spencer than Darwin. Spencer saw evolution as progress along fixed stages, like stepping up the rungs of a ladder. Scholars such as Tylor (Primitive Culture, 1871) and Morgan (Ancient Society, 1877) applied this to human societies, arguing that entire societies progress along fixed stages, from savagery to barbarism to civilisation. Hunter-gatherers were at the bottom of the ladder, and Western societies were at the top.

These ‘progress’ theories are very different to Darwin’s notion of evolution, in which forms diversify over time like a branching tree rather than progress along a fixed ladder. Anthropologists such as Franz Boas convincingly argued against such progress theories, pointing out their inherent racism (assuming Western societies are ‘most advanced’) and lack of empirical support (technologies and customs often diffuse from one society to another, and societies do not inevitably progress along fixed stages).

Due to the rejection of progress theories, all evolutionary theories of culture fell from favour in the social sciences in the early to mid 20th century. Sadly, it was a case of throwing out the baby with the bathwater. During the 20th century, isolated pockets of properly Darwinian cultural evolution sporadically emerged. Donald Campbell (1965) argued for a ‘blind variation and selective retention’ evolutionary theory of human creativity. Karl Popper (1979) proposed that scientific change involves the natural selection of empirically supported hypotheses. Most prominently, Richard Dawkins in The Selfish Gene (1976) proposed the ‘meme’, a cultural replicator equivalent to the gene in biological evolution. However, these ideas had only a modest influence on the academic investigation of cultural evolution.

Arguably, the roots of modern cultural evolution theory are Luca Cavalli-Sforza & Marc Feldman’s Cultural Transmission and Evolution: A Quantitative Approach (1981) and Robert Boyd & Peter Richerson’s Culture and the Evolutionary Process (1985). These scholars created mathematical models of cultural evolution, similar to how population geneticists have created models of genetic evolution. The models assumed that cultural evolution has some similarities with genetic evolution (e.g. vertical transmission from parents), but also some differences (e.g. horizontal transmission from peers). These models created a formal, quantitative basis for cultural evolution theory that avoids many of the problems of verbal theories expressed only in words, which often lead to ambiguity.

In the 1990s and 2000s, phylogenetic methods borrowed from biology were used to reconstruct evolutionary trees of language families, coming full circle with Darwin’s earlier speculations. Phylogenies have also been created of archaeological artifacts and folk tales. Lab experiments, ethnographic fieldwork and historical/archaeological research all began to test the assumptions and predictions of mathematical models. Cognitive anthropologists like Dan Sperber argued for the recognition of the reconstructive nature of cultural transmission, moving away from the assumption of high-fidelity transmission, and creating a distinct ‘cultural attraction’ school. Other researchers study how random copying can explain change in pottery decorations, baby names or the popularity of particular dog breeds.

Today, cultural evolution theory and methods are also applied to investigate many contemporary topics, including warfare, environmental sustainability, social media and religion. Meanwhile there has been an explosion of research into nonhuman animal culture and cultural evolution, in species as varied as chimpanzees, blue tits and humpback whales. There now exists a vibrant field of cultural evolution, with anthropologists, archaeologists, economists, historians, political scientists, psychologists and researchers in many other fields, investigating aspects of cultural change, frequently testing hypotheses and ideas derived from formal theory. This burgeoning interdisciplinary research led to the creation of the Cultural Evolution Society in 2016, with its first conference held in Jena in 2017.