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Human culture changes over time and varies across space. Two main approaches to study cultural evolution have developed in the last fifty years: human behavioural ecology and a suite of perspectives centred on the role of cultural transmission. The latter are often confusingly referred to with the name of the phenomenon they are trying to explain, ‘cultural evolution’. We argue that this is unhelpful and is generating confusion, including the claim that human behavioural ecology disregards cultural evolution. The aim of behavioural ecology is to explain human behaviours, and the vast majority of them are at least to some extent cultural. In addition, culture forms part of the ecology that determines the costs and benefits associated with adopting a behaviour. Thus, human behavioural ecologists have studied cultural evolution from the very beginning, even though they have not focussed on social learning. We explore three examples in detail: kinship systems, religious institutions, and witchcraft belief. We then use the framework offered by Tinbergen’s [1963, Z Tierpsychol, 20(4), 410-433] four evolutionary questions about behaviour to explain how human behavioural ecology and cultural transmission approaches can fruitfully coexist and complement each other. Moreover, we discuss several difficulties with cultural transmission approaches and highlight how the human behavioural ecological view of cultural evolution sometimes diverges from them. We conclude by suggesting that the field can move forward and achieve greater synthesis by exploring how selective processes acting on biological fitness differ from those acting on cultural fitness – and how the two might interact in the cultural evolution of human behaviours.

The term cultural evolution has become popular in the evolutionary human sciences, but it is often unclear what is meant by it. This is generating confusion and misconceptions that are hindering progress in the field. These include the claim that behavioral ecology disregards culture. We argue that these misunderstandings are caused by the unhelpful use of term cultural evolution to identify both a phenomenon—culture changing through time—and a theory to explain it—the potential role of cultural transmission biases in driving this change. We illustrate this point by considering recently published influential studies and opinion pieces. If we are to avoid confusion, the term cultural evolution is best reserved to identify the phenomenon of cultural change. This helps clarify that human behavioral ecologists do not disregard culture, but instead have studied its evolution from the very beginning. Different approaches to the study of human behavior can coexist and complement each other in the framework offered by Tinbergen’s four evolutionary questions. Clarifying key terms is crucial to achieve this synthesis.

The COVID-19 pandemic has brought science into the public eye and to the attention of governments more than ever before. Much of this attention is on work in epidemiology, virology and public health, with most behavioural advice in public health focusing squarely on ‘proximate’ determinants of behaviour. While epidemiological models are powerful tools to predict the spread of disease when human behaviour is stable, most do not incorporate behavioural change. The evolutionary basis of our preferences and the cultural evolutionary dynamics of our beliefs drive behavioural change, so understanding these evolutionary processes can help inform individual and government decision-making in the face of a pandemic.Lay summary: The COVID-19 pandemic has brought behavioural sciences into the public eye: Without vaccinations, stopping the spread of the virus must rely on behaviour change by limiting contact between people. On the face of it, “stop seeing people” sounds simple. In practice, this is hard. Here we outline how an evolutionary perspective on behaviour change can provide additional insights. Evolutionary theory postulates that our psychology and behaviour did not evolve to maximize our health or that of others. Instead, individuals are expected to act to maximise their inclusive fitness (i.e, spreading our genes) – which can lead to a conflict between behaviours that are in the best interests for the individual, and behaviours that stop the spread of the virus. By examining the ultimate explanations of behaviour related to pandemic-management (such as behavioural compliance and social distancing), we conclude that “good of the group” arguments and “one size fits all” policies are unlikely to encourage behaviour change over the long-term. Sustained behaviour change to keep pandemics at bay is much more likely to emerge from environmental change, so governments and policy makers may need to facilitate significant social change – such as improving life experiences for disadvantaged groups.

The causes, consequences, and timing of the rise of moralizing religions in world history have been the focus of intense debate. Progress has been limited by the availability of quantitative data to test competing theories, by divergent ideas regarding both predictor and outcomes variables, and by differences of opinion over methodology. To address all these problems, we utilize Seshat: Global History Databank, a large storehouse of information designed to test theories concerning the evolutionary drivers of social complexity in world history. In addition to the Big Gods hypothesis, which proposes that moralizing religion contributed to the success of increasingly large-scale complex societies, we consider the role of warfare, animal husbandry, and agricultural productivity in the rise of moralizing religions. Using a broad range of new measures of belief in moralizing supernatural punishment, we find strong support for previous research showing that such beliefs did not drive the rise of social complexity in world history. By contrast, our analyses indicate that intergroup warfare, supported by resource availability, played the most significant role in the evolution of both social complexity and moralizing religions. Thus, the correlation between social complexity and moralizing religion would seem to result from shared evolutionary drivers, rather than from strong direct causal relationships between these two variables. The data, methods, and results presented in this paper have been made publicly available online for others to inspect and critique, allowing additional analyses to be run and alternative assumptions to be tested, prior to peer review and publication.

We thank Tosh et al. (1) for their interest in our research (2) but note that their analyses do not undermine the main findings of our article. Their suggestion that polity population divided by polity area should be one of the social complexity dimensions raises a number of issues. What does this ratio mean at large spatial scales, where populations are concentrated in large urban centers and much of the territory is not heavily populated? How are societies distributed across this variable and why? For example, a small-scale “simple” society could have a very high population density if it has access to a rich resource base. Tosh et al. (1) do not provide sufficient information or context to meaningfully … [↵][1]1To whom correspondence should be addressed. Email: t.currie{at}exeter.ac.uk. [1]: #xref-corresp-1-1

Our target article empirically tested the Big Gods Hypothesis which proposes that beliefs in moralizing supernatural punishment (MSP) contributed to the evolution of socio-political complexity (SPC) in world history. We tested this hypothesis using a suite of measures of MSP, SPC, and other potential evolutionary drivers coded in Seshat: Global History Databank. Our analyses indicate that intensity of warfare and productivity of agriculture were major drivers in the evolution of both SPC and MSP. The correlation between social complexity and moralizing religion resulted from shared evolutionary drivers, rather than from direct causal relationships between these two variables. Most commentaries on the target article broadly accept our conclusions, but some argue that alternative measures might be used in future studies before the Big Gods Hypothesis can be conclusively rejected. In this response, we argue that while some of these alternative measures should be developed, they are closely related to the ones we have already adopted. Thus, it seems unlikely that further research will give rise to substantially different outcomes. A particularly fruitful aspect of the discussion is that it illustrates both the pitfalls and productive affordances of transdisciplinary research that seeks to bridge the “two cultures” of the humanities and sciences.