Murayama and Jach raise a key problem in behavioral sciences, to which we suggest evolutionary science can provide a solution. We emphasize the role of adaptive mechanisms in shaping behavior and argue for the integration of hierarchical theories of goal-directed cognition and behavioral flexibility, in order to unravel the motivations behind actions that, in themselves, seem disconnected from adaptive goals.

The commentaries addressed various aspects of our account of historical myths. We respond by clarifying the evolutionary theory of coalitional psychology that underlies our claims (R1). This addresses concerns about the role of fitness interdependence in large groups (R2), cultural transmission processes (R3), alternative routes to nation-building (R4) and the role of proximal mechanisms (R5). Finally, we evaluate alternative theories (R6) and discuss directions for future research (R7).

Peace, the article shows, is achieved by culturally evolved institutions that incentivize positive-sum relationships. We propose that this insight has important consequences for the design of human social cognition. Cues that signal the existence of such institutions should play a prominent role in detecting group membership. We show how this accounts for previous findings and suggest avenues for future research.

One of the most remarkable manifestations of social cohesion in large-scale entities is the belief in a shared, distinct, and ancestral past. Human communities around the world take pride in their ancestral roots, commemorate their long history of shared experiences, and celebrate the distinctiveness of their historical trajectory. Why do humans put so much effort into celebrating a long-gone past? Integrating insights from evolutionary psychology, social psychology, evolutionary anthropology, political science, cultural history, and political economy, we show that the cultural success of historical myths is driven by a specific adaptive challenge for humans: The need to recruit coalitional support to engage in large-scale collective action and prevail in conflicts. By showcasing a long history of cooperation and shared experiences, these myths serve as super-stimuli, activating specific features of social cognition and drawing attention to cues of fitness interdependence. In this account, historical myths can spread within a population without requiring group-level selection, as long as individuals have a vested interest in their propagation and strong psychological motivations to create them. Finally, this framework explains not only the design features of historical myths, but also important patterns in their cross-cultural prevalence, interindividual distribution, and particular content.

We applaud Boyer's attempt to ground the psychology of ownership partly in a cooperative logic. In this commentary, we propose to go further and ground the psychology of ownership solely in a cooperative logic. The predictions of bargaining theory, we argue, completely contradict the actual features of ownership intuitions. Ownership is only about the calculation of mutually beneficial, reciprocal contracts.

Commentators raise fundamental questions about the notion of purity (sect. R1), the architecture of moral cognition (sect. R2), the functional relationship between morality and cooperation (sect. R3), the role of folk-theories of self-control in moral judgment (sect. R4), and the cultural variation of morality (sect. R5). In our response, we address all these issues by clarifying our theory of puritanism, responding to counter-arguments, and incorporating welcome corrections and extensions.

Standard approaches to cultural evolution focus on the recipients or consumers. This does not take into account the fitness costs incurred in producing the behaviours or artefacts that become cultural, i.e. widespread in a social group. We argue that cultural evolution models should focus on these fitness costs and benefits of cultural production, particularly in the domain of ‘symbolic’ culture. In this approach, cultural products can be considered as a part of the extended phenotype of producers, which can affect the fitness of recipients in a positive way (through cooperation) but also in a detrimental way (through manipulation and exploitation). Taking the producers’ perspective may help explain the specific features of many kinds of cultural products.

The Scientific Revolution represents a turning point in the history of humanity. Yet it remains ill-understood, partly because of a lack of quantification. Here, we leverage large datasets of individual biographies (N = 22,943) and present the first estimates of scientific production during the late medieval and early modern period (1300–1850). Our data reveal striking differences across countries, with England and the United Provinces being much more creative than other countries, suggesting that economic development has been key in generating the Scientific Revolution. In line with recent results in behavioural sciences, we show that scientific creativity and economic development are associated with other kinds of creative activities in philosophy, literature, music and the arts, as well as with inclusive institutions and ascetic religiosity, suggesting a common underlying mindset associated with long-term orientation and exploration. Finally, we investigate the interplay between economic development and cultural transmission (the so-called ‘Republic of Letters’) using partially observed Markov models imported from population biology. Surprisingly, the role of horizontal transmission (from one country to another) seems to have been marginal. Beyond the case of science, our results suggest that economic development is an important factor in the evolution of aspects of human culture.

We received several commentaries both challenging and supporting our hypothesis. We thank the commentators for their thoughtful contributions, bringing together alternative hypotheses, complementary explanations, and appropriate corrections to our model. Here, we explain further our hypothesis, using more explicitly the framework of evolutionary social sciences. We first explain what we believe is the ultimate function of fiction in general (i.e., entertainment) and how this hypothesis differs from other evolutionary hypotheses put forward by several commentators. We then turn to the proximate features that make imaginary worlds entertaining and, therefore, culturally successful. We finally explore how these insights may explain the distribution of imaginary worlds across time, space, age, and social classes.

We review recent evidence that game rules, rules of etiquette, and supernatural beliefs, that the authors see as “ritualistic” conventions, are in fact shaped by instrumental inference. In line with such examples, we contend that cultural practices that may appear, from the outside, to be devoid of instrumental utility, could in fact be selectively acquired and preserved because of their perceived utility.

Why do many societies moralize apparently harmless pleasures, such as lust, gluttony, alcohol, drugs, and even music and dance? Why do they erect temperance, asceticism, sobriety, modesty, and piety as cardinal moral virtues? According to existing theories, this puritanical morality cannot be reduced to concerns for harm and fairness: It must emerge from cognitive systems that did not evolve for cooperation (e.g., disgust-based “purity” concerns). Here, we argue that, despite appearances, puritanical morality is no exception to the cooperative function of moral cognition. It emerges in response to a key feature of cooperation, namely that cooperation is (ultimately) a long-term strategy, requiring (proximately) the self-control of appetites for immediate gratification. Puritanical moralizations condemn behaviors which, although inherently harmless, are perceived as indirectly facilitating uncooperative behaviors, by impairing the self-control required to refrain from cheating. Drinking, drugs, immodest clothing, and unruly music and dance are condemned as stimulating short-term impulses, thus facilitating uncooperative behaviors (e.g., violence, adultery, free-riding). Overindulgence in harmless bodily pleasures (e.g., masturbation, gluttony) is perceived as making people slave to their urges, thus altering abilities to resist future antisocial temptations. Daily self-discipline, ascetic temperance, and pious ritual observance are perceived as cultivating the self-control required to honor prosocial obligations. We review psychological, historical, and ethnographic evidence supporting this account. We use this theory to explain the fall of puritanism in western, educated, industrialized, rich, and democratic (WEIRD) societies, and discuss the cultural evolution of puritanical norms. Explaining puritanical norms does not require adding mechanisms unrelated to cooperation in our models of the moral mind.

We propose an approach reconciling the ultimate-level explanations proposed by Savage et al. and Mehr et al. as to why music evolved. We also question the current adaptationist view of culture, which too often fails to disentangle distinct fitness benefits.

Imaginary worlds are extremely successful. The most popular fictions produced in the last few decades contain such a fictional world. They can be found in all fictional media, from novels (e.g., Lord of The Rings and Harry Potter) to films (e.g., Star Wars and Avatar), video games (e.g., The Legend of Zelda and Final Fantasy), graphic novels (e.g., One Piece and Naruto), and TV series (e.g., Star Trek and Game of Thrones), and they date as far back as ancient literature (e.g., the Cyclops Islands in The Odyssey, 850 BCE). Why such a success? Why so much attention devoted to non-existent worlds? In this paper, we propose that imaginary worlds co-opt our preferences for exploration, which have evolved in humans and nonhuman animals alike, to propel individuals toward new environments and new sources of reward. Humans would find imaginary worlds very attractive for the very same reasons, and under the same circumstances, as they are lured by unfamiliar environments in real life. After reviewing research on exploratory preferences in behavioral ecology, environmental esthetics, neuroscience, and evolutionary and developmental psychology, we focus on the sources of their variability across time and space, which we argue can account for the variability of the cultural preference for imaginary worlds. This hypothesis can, therefore, explain the way imaginary worlds evolved culturally, their shape and content, their recent striking success, and their distribution across time and populations.

In this article, we model cultural knowledge as a capital in which individuals invest at a cost. To this end, following other models of cultural evolution, we explicitly consider the investments made by individuals in culture as life history decisions. Our aim is to understand what then determines the dynamics of cultural accumulation. We show that culture can accumulate provided it improves the efficiency of people's lives in such a way as to increase their productivity or, said differently, provided the knowledge created by previous generations improves the ability of subsequent generations to invest in new knowledge. Our central message is that this positive feedback allowing cultural accumulation can occur for many different reasons. It can occur if cultural knowledge increases people's productivity, including in domains that have no connection with knowledge, because it frees up time that people can then spend learning and/or innovating. We also show that it can occur if cultural knowledge, and thus the higher level of resources that results from increased productivity, leads individuals to modify their life history decisions through phenotypic plasticity. Finally, we show that it can occur if technical knowledge reduces the effective cost of its own acquisition via division of labour. These results suggest that culture should not be defined only as a set of knowledge and skills but, more generally, as all the capital that has been produced by previous generations and that continues to affect current generations.

I am grateful to have received so many stimulating commentaries from interested colleagues regarding the psychological origins of the Industrial Revolution and the role of evolutionary theory in understanding historical phenomena. Commentators criticized, extended, and explored the implications of the perspective I presented, and I wholeheartedly agree with many commentaries that more work is needed. In this response, I thus focus on what is needed to further test the psychological origins of the Industrial Revolution. Specifically, I argue, in agreement with many commentators, that we need: (1) better data about standards of living, psychological preferences, and innovation rates (sect. R1); (2) better models to understand the role of resources (and not just mortality) in driving cultural evolution and the multiple aspects of the behavioral constellation of affluence (sect. R2); and (3) better predictions and better statistical instruments to disentangle the possible mechanisms behind the rise of innovativeness (genetic selection, rational choice, and phenotypic plasticity) (sect. R3).

We applaud Boyer & Petersen's (B&P's) article on economic folk beliefs. We believe that it is crucial for the future of democracy to identify the cognitive systems through which people form their beliefs about the working of the economy. In this commentary, we put forward the idea that, although many systems are involved, fairness is probably the main driver of folk-economic beliefs.

Since the Industrial Revolution, human societies have experienced high and sustained rates of economic growth. Recent explanations of this sudden and massive change in economic history have held that modern growth results from an acceleration of innovation. But it is unclear why the rate of innovation drastically accelerated in England in the eighteenth century. An important factor might be the alteration of individual preferences with regard to innovation resulting from the unprecedented living standards of the English during that period, for two reasons. First, recent developments in economic history challenge the standard Malthusian view according to which living standards were stagnant until the Industrial Revolution. Pre-industrial England enjoyed a level of affluence that was unprecedented in history. Second, behavioral sciences have demonstrated that the human brain is designed to respond adaptively to variations in resources in the local environment. In particular, Life History Theory, a branch of evolutionary biology, suggests that a more favorable environment (high resources, low mortality) should trigger the expression of future-oriented preferences. In this paper, I argue that some of these psychological traits – a lower level of time discounting, a higher level of optimism, decreased materialistic orientation, and a higher level of trust in others – are likely to increase the rate of innovation. I review the evidence regarding the impact of affluence on preferences in contemporary as well as past populations, and conclude that the impact of affluence on neurocognitive systems may partly explain the modern acceleration of technological innovations and the associated economic growth.

I applaud Singh's proposition to use evolutionary psychology to explain the recurrence of shamanistic beliefs. Here, I suggest that evolutionary mechanisms (i.e., life history theory) also can explain the variability of the distribution of shamanism. When resources are abundant, individuals become more patient and more open minded to the point that science becomes cognitively attractive and may replace magic.

Pepper & Nettle explain the behavioral constellation of deprivation (BCD) in terms of differences in collection risk (i.e., the probability of collecting a reward after some delay) between high- and low-socioeconomic-status (SES) populations. We argue that a proper explanation should also include the costs of waiting per se, which are paid even when the benefits are guaranteed.