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People willingly follow norms and values, often incurring material costs. This behaviour supposedly stems from evolved norm psychology, contributing to large-scale cooperation among humans. It has been argued that cooperation is influenced by two types of norms: injunctive and descriptive. This study theoretically explores the socialisation of humans under these norms. Our agent-based model simulates scenarios where diverse agents with heterogeneous norm psychologies engage in collective action to maximise their utility functions that capture three motives: gaining material payoff, following injunctive and descriptive norms. Multilevel selective pressure drives the evolution of norm psychology that affects the utility function. Further, we develop a model with exapted conformity, assuming selective advantage for descriptive norm psychology. We show that norm psychology can evolve via cultural group selection. We then identify two normative conditions that favour the evolution of norm psychology, and therefore cooperation: injunctive norms promoting punitive behaviour and descriptive norms. Furthermore, we delineate different characteristics of cooperative societies under these two conditions and explore the potential for a macro transition between them. Together, our results validate the emergence of large-scale cooperative societies through social norms and suggest complementary roles that conformity and punishment play in human prosociality.

Cultural group selection theorists propose that humans evolved prosocial preferences. These claims revolve largely around the centrality of punishment in cultural groups, which helped to eliminate free riders. The purpose of this paper is to explore whether distinguishing between free-riding as an action, and free riders as entities, undermines or supports this view. I develop three individual-based models of the Prisoner’s Dilemma. The first model shows that strong reciprocity removes overt freeriders from a population, and maintains a high rate of cooperation. In the second, I introduce individuals that mimic cooperative preferences, but who defect when they trick opponents into cooperating. I show that strong reciprocity is robust against this strategy, but not because individuals are replaced by strong reciprocators. Finally, I introduce a third strategy, covert mimicry, where some mimics may defect without detection. I draw attention to the problem highlighted in these models, which is that cooperation may be maintained in populations only because freeriders are not presented with the opportunity to defect. I discuss this problem in the context of cultural group selection and the human capacity for innovation, and suggest that hypotheses relying on prosocial preferences for maintaining cooperation require some revision. [ABSTRACT FROM AUTHOR]

People willingly follow norms and values, often incurring material costs. This behaviour supposedly stems from evolved norm psychology, contributing to large-scale cooperation among humans. It has been argued that cooperation is influenced by two types of norms: injunctive and descriptive. This study theoretically explores the socialisation of humans under these norms. Our agent-based model simulates scenarios where diverse agents with heterogeneous norm psychologies engage in collective action to maximise their utility functions that capture three motives: gaining material payoff, following injunctive and descriptive norms. Multilevel selective pressure drives the evolution of norm psychology that affects the utility function. Further, we develop a model with exapted conformity, assuming selective advantage for descriptive norm psychology. We show that norm psychology can evolve via cultural group selection. We then identify two normative conditions that favour the evolution of norm psychology, and therefore cooperation: injunctive norms promoting punitive behaviour and descriptive norms. Furthermore, we delineate different characteristics of cooperative societies under these two conditions and explore the potential for a macro transition between them. Together, our results validate the emergence of large-scale cooperative societies through social norms and suggest complementary roles that conformity and punishment play in human prosociality., Competing Interests: The authors declare no conflict of interest existing., (© The Author(s) 2024.)

Current adaptationist approaches view religion as a system of beliefs, behaviours, social norms, taboos and collective rituals, which enforce social cohesion and intragroup solidarity that lead to group cooperation and coordination. These prosocial effects then translate into success in between-group competition. Cultural group selection is seen as the process that led to the emergence of religion as a cultural adaptation that enables the persistence of cooperative social groups. This article applies this theoretical approach to the so-called Old Believers: a diverse and fractioned branch of Russian Orthodox Christianity, whose history is marked by apocalyptic worldviews and antagonism towards state powers and the Russian Orthodox Church. Since their split with the Russian Orthodox Church in the 17th century, the Old Believers evolved towards egalitarian communities, asceticism, isolationism and traditionalism. The author argues that Old Believers can be in many respects viewed as prototypic examples of how religious systems promote social cohesion, in-group solidarity, identity and commitment. Yet, contrary to what the theory assumes (or at least emphasizes), the very same collective rituals, social norms, supernatural beliefs and taboos, and their systemic interdependence, can lead to group harmful outcomes (e.g., splintering, excessive celibacy, mass suicide). In other words, high levels of in-group prosociality linked to religion cannot be simply viewed as exclusively mediating group benefits. [ABSTRACT FROM AUTHOR]

Abstract: Morality can be adaptive or maladaptive. From this fact come polarizing disputes on the meta-ethical status of moral adaptation. The realist tracking account of morality claims that it is possible to track objective moral truths and that these truths correspond to moral rules that are adaptive. In contrast, evolutionary anti-realism rejects the existence of moral objectivity and thus asserts that adaptive moral rules cannot represent objective moral truths, since those truths do not exist. This article develops a novel evolutionary view of natural law to defend the realist tracking account. It argues that we can identify objective moral truths through cultural group selection and that adaptive moral rules are likely to reflect such truths. [ABSTRACT FROM AUTHOR]

Influential thinkers such as Young, Sugden, Binmore, and Skyrms have developed game-theoretic accounts of the emergence, persistence and evolution of social contracts. Social contracts are sets of commonly understood rules that govern cooperative social interaction within societies. These naturalistic accounts provide us with valuable and important insights into the foundations of human societies. However, current naturalistic theories focus mainly on how social contracts solve coordination problems in which the interests of the individual participants are (relatively) aligned, not competition problems in which individual interests compete with group interests (and in which there are no group beneficial Nash equilibrium available). In response, I set out to build on those theories and provide a (more) comprehensive naturalistic account of the emergence, persistence and evolution of social contracts. My central claim is that social contracts have culturally evolved to solve cooperation problems, which include both coordination and competition problems. I argue that solutions to coordination problems (which I spell out) emerge from “within-group” dynamics, while solutions to competition problems (which I also spell out) result largely from “between-group” dynamics.

Humans often behave altruistically towards strangers with no chance of reciprocation. From an evolutionary perspective, this is puzzling. The evolution of altruistic cooperative behavior—in which an organism's action reduces its fitness and increases the fitness of another organism (e.g. by sharing food)—only makes sense when it is directed at genetically related organisms (kin selection) or when one can expect the favor to be returned (reciprocal altruism). Therefore, evolutionary theorists such as Sober and Wilson have argued that we should revise Neo-Darwininian evolutionary theory. They argue that human altruism evolved through group selection in which groups of altruists were naturally selected because they had a comparative advantage over other groups. Wilson and Sober's hypothesis attracted followers but is rejected by most of their peers. The heated debate between advocates and critics of group selection often suffers from a lack of conceptual clarity. In response, I set out to clearly distinguish 'genetic' from 'cultural' group selection (developed by Boyd, Richerson & Henrich) and argue that the latter does not face the potentially debilitating problems plaguing the former. I defend the claim that human altruistic dispositions evolved through cultural group selection and gene-culture coevolution and offer empirical evidence in support. I also argue that actual altruistic behavior often goes beyond the kind of behavior humans have evolved to display. Conscious and voluntary reasoning processes, I show, have an important role in altruistic behavior. This is often overlooked in the scientific literature on human altruism. [ABSTRACT FROM AUTHOR]

Evolutionary Transitions in Individuality (ETI) have been responsible for the major transitions in levels of selection and individuality in natural history, such as the origins of prokaryotic and eukaryotic cells, multicellular organisms, and eusocial insects. The integrated hierarchical organization of life thereby emerged as groups of individuals repeatedly evolved into new and more complex kinds of individuals. The Social Protocell Hypothesis (SPH) proposes that the integrated hierarchical organization of human culture can also be understood as the outcome of an ETI—one that produced a "cultural organism" (a "sociont") from a substrate of socially learned traditions that were contained in growing and dividing social communities. The SPH predicts that a threshold degree of evolutionary individuality would have been achieved by 2.0–2.5 Mya, followed by an increasing degree of evolutionary individuality as the ETI unfolded. We here assess the SPH by applying a battery of criteria—developed to assess evolutionary individuality in biological units—to cultural units across the evolutionary history of Homo. We find an increasing agreement with these criteria, which buttresses the claim that an ETI occurred in the cultural realm. [ABSTRACT FROM AUTHOR]

To resolve the major controversy about why prosocial behaviors persist in large‐scale human societies, we propose that two questions need to be answered. First, how do social interactions in small‐scale and large‐scale societies differ? By reviewing the exchange and collective‐action dilemmas in both small‐scale and large‐scale societies, we show they are not different. Second, are individual decision‐making mechanisms driven by self‐interest? We extract from the literature three types of individual decision‐making mechanism, which differ in their social influence and sensitivity to self‐interest, to conclude that humans interacting with non‐relatives are largely driven by self‐interest. We then ask: what was the key mechanism that allowed prosocial behaviors to continue as societies grew? We show the key role played by new social interaction mechanisms—change in the rules of exchange and collective‐action dilemmas—devised by the interacting individuals, which allow for self‐interested individuals to remain prosocial as societies grow. [ABSTRACT FROM AUTHOR]

Human behavior and collective actions are strongly affected by social institutions. A question of great theoretical and practical importance is how successful social institutions get established and spread across groups and societies. Here, using institutionalized punishment in small-scale societies as an example, we contrast two prominent mechanisms - selective imitation and self-interested design - with respect to their ability to converge to cooperative social institutions. While selective imitation has received a great deal of attention in studies of social and cultural evolution, the theoretical toolbox for studying self-interested design is limited. Recently Perry, Shrestha, Vose, and Gavrilets (2018) expanded this toolbox by introducing a novel approach, which they called foresight, generalizing standard myopic best response for the case of individuals with a bounded ability to anticipate actions of their group-mates and care about future payoffs. Here we apply this approach to two general types of collective action – "us vs. nature" and "us vs. them" games. We consider groups composed by a number of regular members producing collective good and a leader monitoring and punishing free-riders. Our results show that foresight increases leaders' willingness to punish free-riders. This, in turn, leads to increased production and the emergence of an effective institution for collective action. We also observed that largely similar outcomes can be achieved by selective imitation, as argued earlier. Selective imitation by leaders (i.e. cultural group selection) outperforms self-interested design if leaders strongly discount the future. Foresight and selective imitation can interact synergistically leading to a faster convergence to an equilibrium. Our approach is applicable to many other types of social institutions and collective action. [ABSTRACT FROM AUTHOR]

Cultural group selection has been proposed as an explanation for humans’ highly cooperative nature. This theory argues that social learning mechanisms, combined with rewards and punishment, can stabilise any group behaviour, cooperative or not. Equilibrium selection can then operate, resulting in cooperative groups outcompeting less-cooperative groups. This process may explain the widespread cooperation between non-kin observed in humans, which is sometimes claimed to be altruistic. This review explores the assumptions of cultural group selection to assess whether it provides a convincing explanation for human cooperation. Although competition between cultural groups certainly occurs, it is unclear whether this process depends on specific social learning mechanisms (e.g. conformism) or a norm psychology (to indiscriminately punish norm-violators) to stabilise groups at different equilibria as proposed by existing cultural group selection models. Rather than unquestioningly adopt group norms and institutions, individuals and groups appear to evaluate, design and shape them for self-interested reasons (where possible). As individual fitness is frequently tied to group fitness, this often coincides with constructing group-beneficial norms and institutions, especially when groups are in conflict. While culture is a vital component underlying our species’ success, the extent to which current conceptions of cultural group selection reflect human cooperative evolution remains unclear.

Cognitive science of religion (CSR) has increased influence in religious studies, the resistance of religious protectionists notwithstanding. CSR's most provocative work stresses the role of implicit cognition in explaining religious thought and conduct. Exhibiting explanatory pluralism, CSR seeks integrative accounts across the social, psychological, and brain sciences. CSR reflects prominent trends in the cognitive sciences generally. First, CSR is giving greater attention to the new tools and findings of cognitive neuroscience. Second, CSR researchers have done carefully designed, nonlaboratory studies of experience, incorporating precise physiological measures, obtaining astonishing findings about the experiences of ritual participants and observers. Third, CSR theorists have advanced evolutionary hypotheses about religions from eight perspectives (cross‐indexing three levels of selection with three mechanisms of selection). Cultural group selectionists headline credibility enhancing displays and Big Gods in the religious consolidation of large‐scale societies. Other CSR researchers marshal counterevidence and advance alternative hypotheses. CSR findings are incompatible with the New Atheists' projects on two fronts. [ABSTRACT FROM AUTHOR]

Despite remarkable empirical and methodological advances, our theoretical understanding of the evolutionary processes that made us human remains fragmented and contentious. Here, we make the radical proposition that the cultural communities within which Homo emerged may be understood as a novel exotic form of organism. The argument begins from a deep congruence between robust features of Pan community life cycles and protocell models of the origins of life. We argue that if a cultural tradition, meeting certain requirements, arises in the context of such a "social protocell," the outcome will be an evolutionary transition in individuality whereby traditions and hominins coalesce into a macroscopic bio-socio-technical system, with an organismal organization that is culturally inherited through irreversible fission events on the community level. We refer to the resulting hypothetical evolutionary individual as a "sociont." The social protocell provides a preadapted source of alignment of fitness interests that addresses a number of open questions about the origins of shared adaptive cultural organization, and the derived genetic (and highly unusual) adaptations that support them. Also, social cooperation between hominins is no longer in exclusive focus since cooperation among traditions becomes salient in this model. This provides novel avenues for explanation. We go on to hypothesize that the fate of the hominin in such a setting would be mutualistic coadaptation into a part-whole relation with the sociont, and we propose that the unusual suite of derived features in Homo is consistent with this hypothesis. [ABSTRACT FROM AUTHOR]

The collective action problem can easily undermine cooperation in groups. Recent work has shown that within-group heterogeneity can under some conditions promote voluntary provisioning of collective goods. Here we generalize this work for the case when individuals can not only contribute to the production of collective goods, but also punish free-riders. To do this, we extend the standard theory by allowing individuals to have limited foresight so they can anticipate actions of their group-mates. For humans, this is a realistic assumption because we possess a “theory of mind”. We use agent-based simulations to study collective actions that aim to overcome challenges from nature or win competition with neighboring groups. We contrast the dynamics of collective action in egalitarian and hierarchical groups. We show that foresight allows groups to overcome both the first- and second-order free-rider problems. While foresight increases cooperation, it does not necessarily result in higher payoffs. We show that while between-group conflicts promotes within-group cooperation, the effects of cultural group selection on cooperation are relatively small. Our models predict the emergence of a division of labor in which more powerful individuals specialize in punishment while less powerful individuals mostly contribute to the production of collective goods. [ABSTRACT FROM AUTHOR]

Ethnicity looks something like kinship on a larger scale. The same math can be used to measure genetic similarity within ethnic/racial groups and relatedness within families. For example, members of the same continental race are about as related ( r = 0.18–0.26) as half-siblings ( r = 0.25). However (contrary to some claims) the theory of kin selection does not apply straightforwardly to ethnicity, because inclusive fitness calculations based on Hamilton's rule break down when there are complicated social interactions within groups, and/or groups are large and long-lasting. A more promising approach is a theory of ethnic group selection, a special case of cultural group selection. An elementary model shows that the genetic assimilation of a socially enforced cultural regime can promote group solidarity and lead to the regulation of recruitment to groups, and to altruism between groups, based on genetic similarity – in short, to ethnic nepotism. Several lines of evidence, from historical population genetics and political psychology, are relevant here. [ABSTRACT FROM AUTHOR]

Relatively little is known about how resource conservation practices and institutions emerge. We examine the historical emergence of territoriality and conservation rules in Maine's lobstering industry, using a cultural evolutionary perspective. Cultural evolution suggests that cultural adaptations such as practices and institutions arise as a result of evolutionary selection pressure. The cultural multilevel selection framework of Waring et al. (Ecol Soc, 2015) further proposes that group cultural adaptations tend to emerge at a level of social organization corresponding to the underlying dilemma. Drawing on detailed history and ethnography, we conduct a retrospective assessment to determine which levels of social organization experienced selection pressures that might explain the emergence of lobstering territoriality and conservation practices we observe in history. The evidence strongly suggests that informal territoriality evolved by selection on harbor gang behavior, while some conservation practices spread via selection at other levels from individuals to regional lobstering zones. We identify two apparent historical shifts in the dominant level of selection for these practices over the history of the industry and discuss the implications of this trajectory for the evolution of lobster management in the Gulf of Maine. [ABSTRACT FROM AUTHOR]

Proponents of cognitive Situationism argue that the human mind is embodied, embedded in both natural and social-cultural environments and extended creating both extended and distributed cognition. Anti-situationists reject all or some of these claims. I argue that four major objections to extended cognition: (1) the mark of the cognitive, (2) the function-identity fallacy, (3) cognitive bloat, and (4) scientific irrelevance lose much of their sting in the case of distributed cognition, the extension of cognitive agency to a group of cognitive agents, such as a scientific research team. However, I claim that a crucial fifth challenge, that advocates of the extended mind commit the causal-constitution fallacy, has yet to be satisfactorily addressed. I focus on Spyridon Palermos’ use of dynamic systems theory to refute this charge and I argue that his appeal to dynamic systems theory as a way of understanding system-constitution fails. Instead, I suggest a social-cultural group selection hypothesis for understanding system-constitution. But, I leave it for another day to elaborate that hypothesis’ empirical plausibility. [ABSTRACT FROM AUTHOR]

The observation that politics makes strange bedfellows may be hackneyed, but it is also often true: Politicians and other actors in the policy process routinely align themselves on specific issues with actors with whom they otherwise have broad disagreements. This fits with social psychological research showing that humans have a coalitional psychology that is remarkably flexible, allowing us to feel strong bonds toward the coalitions to which we belong but to also break those bonds and move on to new coalitions when circumstances change. How is this flexibility possible? Here we examine the possible ways in which evolutionary forces helped shape our species’ trademark flexible coalitional psychology, focusing in particular on gene-culture coevolution and cultural group selection. We conclude with some examples of coordinated policy action among erstwhile foes in contemporary politics. [ABSTRACT FROM AUTHOR]

Empirical research has identified various institutions that improve resource longevity by supporting individual resource conservation. However, the mechanisms by which these institutions emerge have not been established. We speculate that economic institutions which support resource conservation, such as property regimes and systems of production, may emerge via a process of cultural group selection amongst social-ecological systems. To explore this proposition, we develop a multilevel selection model of resource management institutions with endogenous group dynamics. The endogenous design permits us to determine whether a given social adaptation is due to individual or group-level evolution. We demonstrate how resource conservation and supporting economic institutions coevolve, and reveal when cultural group selection is involved. In the model, sustainable societies emerge in only a minority of cases. Simulations reveal that property norms facilitate sustainable outcomes most, followed by social group marking, and production norms. We describe the institutional transitions which occur along the evolutionary trajectory most likely to achieve sustainability. Analysis of the model reveals that when groups compete indirectly for survival in a harsh environment cultural group selection favors institutions that support resource conservation. However, when groups compete for abundant resources institutions emerge to support overconsumption. [ABSTRACT FROM AUTHOR]

When selection increases the frequency of a beneficial gene substitution it can also increase the frequencies of linked neutral alleles through a process called genetic hitchhiking. A model built to investigate reduced genetic diversity in Pleistocene hominins shows that genetic hitchhiking can have a strong effect on neutral diversity in the presence of culturally mediated migration. Under conditions in which genetic and cultural variants are transmitted symmetrically, neutral genes may also hitchhike to higher frequencies on the coattails of adaptive cultural traits through a process called cultural hitchhiking. Cultural hitchhiking has been proposed to explain why some species of matrilineal whales display relatively low levels of mitochondrial DNA diversity, and it may be applicable to humans as well. This paper provides a critical review of recent models of both types of hitch­­hi­king in socially structured populations. The models’ assumptions and predictions are compared and discussed in the hope that studies of reduced genetic diversity in humans might improve our understanding of reduced genetic diversity in other species, and vice versa [Current Zoology 58 (1): 287-297, 2012].

Humans regularly help strangers, even when interactions are apparently unobserved and unlikely to be repeated. Such situations have been simulated in the laboratory using anonymous one-shot games (e.g. prisoner's dilemma) where the payoff matrices used make helping biologically altruistic. As in real-life, participants often cooperate in the lab in these one-shot games with non-relatives, despite that fact that helping is under negative selection under these circumstances. Two broad explanations for such behavior prevail. The 'big mistake' or 'mismatch' theorists argue that behavior is constrained by psychological mechanisms that evolved predominantly in the context of repeated interactions with known individuals. In contrast, the cultural group selection theorists posit that humans have been selected to cooperate in anonymous one-shot interactions due to strong between-group competition, which creates interdependence among in-group members. We present these two hypotheses before discussing alternative routes by which humans could increase their direct fitness by cooperating with strangers under natural conditions. In doing so, we explain why the standard lab games do not capture real-life in various important aspects. First, asymmetries in the cost of perceptual errors regarding the context of the interaction (one-shot versus repeated; anonymous versus public) might have selected for strategies that minimize the chance of making costly behavioral errors. Second, helping strangers might be a successful strategy for identifying other cooperative individuals in the population, where partner choice can turn strangers into interaction partners. Third, in many real-world situations individuals are able to parcel investments such that a one-shot interaction is turned into a repeated game of many decisions. Finally, in contrast to the assumptions of the prisoner's dilemma model, it is possible that benefits of cooperation follow a non-linear function of investment. Non-li

We consider a model of multilevel selection and the evolution of institutions that distribute power in the form of influence in a group's collective interactions with other groups. In the absence of direct group-level interactions, groups with the most cooperative members will outcompete less cooperative groups, while within any group the least cooperative members will be the most successful. Introducing group-level interactions, however, such as raiding or warfare, changes the selective landscape for groups. Our model suggests that as the global population becomes more integrated and the rate of intergroup conflict increases, selection increasingly favors unequally distributed power structures, where individual influence is weighted by acquired resources. The advantage to less democratic groups rests in their ability to facilitate selection for cooperative strategies – involving cooperation both among themselves and with outsiders – in order to produce the resources necessary to fuel their success in inter-group conflicts, while simultaneously selecting for leaders (and corresponding collective behavior) who are unburdened with those same prosocial norms. The coevolution of cooperative social norms and institutions of power facilitates the emergence of a leadership class of the selfish and has implications for theories of inequality, structures of governance, non-cooperative personality traits, and hierarchy. Our findings suggest an amendment to the well-known doctrine of multilevel selection that “Selfishness beats altruism within groups. Altruistic groups beat selfish groups.” In an interconnected world, altruistic groups led by selfish individuals can beat them both. [ABSTRACT FROM AUTHOR]

Morality can be adaptive or maladaptive. From this fact come polarizing disputes on the meta-ethical status of moral adaptation. The realist tracking account of morality claims that it is possible to track objective moral truths and that these truths correspond to moral rules that are adaptive. In contrast, evolutionary anti-realism rejects the existence of moral objectivity and thus asserts that adaptive moral rules cannot represent objective moral truths, since those truths do not exist. This article develops a novel evolutionary view of natural law to defend the realist tracking account. It argues that we can identify objective moral truths through cultural group selection and that adaptive moral rules are likely to reflect such truths.

Humans regularly help strangers, even when interactions are apparently unobserved and unlikely to be repeated. Such situations have been simulated in the laboratory using anonymous one-shot games (e.g., prisoner's dilemma) where the payoff matrices used make helping biologically altruistic. As in real-life, participants often cooperate in the lab in these one-shot games with non-relatives, despite that fact that helping is under negative selection under these circumstances. Two broad explanations for such behavior prevail. The "big mistake" or "mismatch" theorists argue that behavior is constrained by psychological mechanisms that evolved predominantly in the context of repeated interactions with known individuals. In contrast, the cultural group selection theorists posit that humans have been selected to cooperate in anonymous one-shot interactions due to strong between-group competition, which creates interdependence among in-group members. We present these two hypotheses before discussing alternative routes by which humans could increase their direct fitness by cooperating with strangers under natural conditions. In doing so, we explain why the standard lab games do not capture real-life in various important aspects. First, asymmetries in the cost of perceptual errors regarding the context of the interaction (one-shot vs. repeated; anonymous vs. public) might have selected for strategies that minimize the chance of making costly behavioral errors. Second, helping strangers might be a successful strategy for identifying other cooperative individuals in the population, where partner choice can turn strangers into interaction partners. Third, in contrast to the assumptions of the prisoner's dilemma model, it is possible that benefits of cooperation follow a non-linear function of investment. Nonlinear benefits result in negative frequency dependence even in one-shot games. Finally, in many real-world situations individuals are able to parcel investments such that a one-shot interaction is turned into a repeated game of many decisions. [ABSTRACT FROM AUTHOR]

The docility hypothesis holds that human social learning produces genuinely altruistic behaviors as a maladaptive by-product. This article examines five possible sources of such altruistic mistakes. The first two mechanisms, the smoke- detector principle and the cost- accuracy tradeoff, are not specifically linked to social learning. Both predict that it may be adaptive for cooperators to allow some altruistic mistakes to happen, as long as those mistakes are rare and cost little. The other three mechanisms are specific to social learning: Through culture, individuals may come to adopt altruistic norms selected at the group level. Culture may provide people with cheap, accessible, but occasionally mediocre information that they are too reliant upon-a kind of informational dumping. Lastly, people may copy sources good to follow in one domain (like technology) but not in another (cooperation), thus committing calibration errors. I argue that those sources of errors are unlikely to lead to important amounts of altruism toward non-kin. Experimental evidence shows humans to be sufficiently skeptical, discriminative, and conscious of their own interest to avoid such altruistic mistakes in most cases. Docile altruism is unlikely to be an important aspect of human cooperation. [ABSTRACT FROM AUTHOR]

The aim of this paper is to provide non-specialist readers with an introduction to some current controversies surrounding the application of evolutionary theory to human behaviour at the intersection of biology, psychology and anthropology. We review the three major contemporary sub-fields; namely Human Behavioural Ecology, Evolutionary Psychology and Cultural Evolution, and we compare their views on maladaptive behaviour, the proximal mechanisms of cultural transmission, and the relationship between human cognition and culture. For example, we show that the sub-fields vary in the amount of maladaptive behaviour that is predicted to occur in modern environments; Human Behavioural Ecologists start with the expectation that behaviour will be optimal, while Evolutionary Psychologists emphasize cases of 'mis-match' between modern environments and domain-specific, evolved psychological mechanisms. Cultural Evolutionists argue that social learning processes are effective at providing solutions to novel problems and describe how relatively weak, general-purpose learning mechanisms, alongside accurate cultural transmission, can lead to the cumulative evolution of adaptive cultural complexity but also sometimes to maladaptative behaviour. We then describe how the sub-fields view cooperative behaviour between non-kin, as an example of where the differences between the sub-fields are relevant to the economics community, and we discuss the hypothesis that a history of inter-group competition can explain the evolution of non-kin cooperation. We conclude that a complete understanding of human behaviour requires insights from all three fields and that many scholars no longer view them as distinct. [ABSTRACT FROM AUTHOR]

Many of the most important properties of human groups – including properties that may give one group an evolutionary advantage over another – are properly defined only at the level of group organization. Yet at present, most work on the evolution of culture has focused solely on the transmission of individual-level traits. I propose a conceptual extension of the theory of cultural evolution, particularly related to the evolutionary competition between cultural groups. The key concept in this extension is the emergent group-level trait. This type of trait is characterized by the structured organization of differentiated individuals and constitutes a unit of selection that is qualitatively different from selection on groups as defined by traditional multilevel selection (MLS) theory. As a corollary, I argue that the traditional focus on cooperation as the defining feature of human societies has missed an essential feature of cooperative groups. Traditional models of cooperation assume that interacting with one cooperator is equivalent to interacting with any other. However, human groups involve differential roles, meaning that receiving aid from one individual is often preferred to receiving aid from another. In this target article, I discuss the emergence and evolution of group-level traits and the implications for the theory of cultural evolution, including ramifications for the evolution of human cooperation, technology, and cultural institutions, and for the equivalency of multilevel selection and inclusive fitness approaches. [ABSTRACT FROM AUTHOR]

Transmitted culture can be viewed as an inheritance system somewhat independent of genes that is subject to processes of descent with modification in its own right. Although many authors have conceptualized cultural change as a Darwinian process, there is no generally agreed formal framework for defining key concepts such as natural selection, fitness, relatedness and altruism for the cultural case. Here, we present and explore such a framework using the Price equation. Assuming an isolated, independently measurable culturally transmitted trait, we show that cultural natural selection maximizes cultural fitness, a distinct quantity from genetic fitness, and also that cultural relatedness and cultural altruism are not reducible to or necessarily related to their genetic counterparts. We show that antagonistic coevolution will occur between genes and culture whenever cultural fitness is not perfectly aligned with genetic fitness, as genetic selection will shape psychological mechanisms to avoid susceptibility to cultural traits that bear a genetic fitness cost. We discuss the difficulties with conceptualizing cultural change using the framework of evolutionary theory, the degree to which cultural evolution is autonomous from genetic evolution, and the extent to which cultural change should be seen as a Darwinian process. We argue that the nonselection components of evolutionary change are much more important for culture than for genes, and that this and other important differences from the genetic case mean that different approaches and emphases are needed for cultural than genetic processes. [ABSTRACT FROM AUTHOR]

Collective action, or the large-scale cooperation in the pursuit of public goods, has been suggested to have evolved through cultural group selection. Previous research suggests that the costly punishment of group members who do not contribute to public goods plays an important role in the resolution of collective action dilemmas. If large-scale cooperation sustained by the punishment of defectors has evolved through the mechanism of cultural group selection, two implications regarding costly punishment follow: (1) that people are more willing to punish defecting group members in a situation of intergroup competition than in a single-group social dilemma game and (2) that levels of 'perverse' punishment of cooperators are not affected by intergroup competition. We find confirmation for these hypotheses. However, we find that the effect of intergroup competition on the punishment of defectors is fully explained by the stronger conditionality of punishment on expected punishment levels in the competition condition. [ABSTRACT FROM AUTHOR]

When selection increases the frequency of a beneficial gene substitution it can also increase the frequencies of linked neutral alleles through a process called genetic hitchhiking. A model built to investigate reduced genetic diversity in Pleistocene hominins shows that genetic hitchhiking can have a strong effect on neutral diversity in the presence of culturally mediated migration. Under conditions in which genetic and cultural variants are transmitted symmetrically, neutral genes may also hitchhike to higher frequencies on the coattails of adaptive cultural traits through a process called cultural hitchhiking. Cultural hitchhiking has been proposed to explain why some species of matrilineal whales display relatively low levels of mitochondrial DNA diversity, and it may be applicable to humans as well. This paper provides a critical review of recent models of both types of hitchhiking in socially structured populations. The models' assumptions and predictions are compared and discussed in the hope that studies of reduced genetic diversity in humans might improve our understanding of reduced genetic diversity in other species, and vice versa. [ABSTRACT FROM AUTHOR]

Understanding cooperation and punishment in small-scale societies is crucial for explaining the origins of human cooperation. We studied warfare among the Turkana, a politically uncentralized, egalitarian, nomadic pastoral society in East Africa. Based on a representative sample of 88 recent raids, we show that the Turkana sustain costly cooperation in combat at a remarkably large scale, at least in part, through punishment of free-riders. Raiding parties comprised several hundred warriors and participants are not kin or day-to-day interactants. Warriors incur substantial risk of death and produce collective benefits. Cowardice and desertions occur, and are punished by community-imposed sanctions, including collective corporal punishment and fines. Furthermore, Turkana norms governing warfare benefit the ethnolinguistic group, a population of a half-million people, at the expense of smaller social groupings. These results challenge current views that punishment is unimportant in small-scale societies and that human cooperation evolved in small groups of kin and familiar individuals. Instead, these results suggest that cooperation at the larger scale of ethnolinguistic units enforced by third-party sanctions could have a deep evolutionary history in the human species. [ABSTRACT FROM AUTHOR]

Abstract: This paper lays out an evolutionary theory for the cognitive foundations and cultural emergence of the extravagant displays (e.g., ritual mutilation, animal sacrifice and martyrdom) that have so tantalized social scientists, as well as more mundane actions that influence cultural learning and historical processes. In Part I, I use the logic of natural selection to build a theory for how and why seemingly costly displays influence the cognitive processes associated with cultural learning — why do “actions speak louder than words?” The core idea is that cultural learners can both avoid being manipulated by their models (those they are inclined to learn from) and more accurately assess their belief commitment by attending to displays or actions by the model that would seem costly to the model if he held beliefs different from those he expresses verbally. Part II examines the implications for cultural evolution of this learning bias in a simple evolutionary model. The model reveals the conditions under which this evolved bias can create stable sets of interlocking beliefs and practices, including quite costly practices. Part III explores how cultural evolution, driven by competition among groups or institutions stabilized at alternative sets of these interlocking belief-practice combinations, has led to the association of costly acts, often in the form of rituals, with deeper commitments to group beneficial ideologies, higher levels of cooperation within groups, and greater success in competition with other groups or institutions. I close by discussing the broader implications of these ideas for understanding various aspects of religious phenomena. [Copyright &y& Elsevier]

This essay critiques dual-inheritance theory as presented in Peter Richerson and Robert Boyd's book Not by Genes Alone: How Culture Transformed Human Evolution (2005). The theory states that culture became prominent in human evolution because it allowed relatively rapid adaptation to changing environments by means of imitation. Imitating the behavior of other members of one's community produces adaptive behaviors more readily than either genetic evolution or individual learning. Imitation follows a number of patterns: imitating high-status individuals, imitating the most common forms of behavior, imitating behaviors perceived to be the most effective solutions to various problems relevant to survival. This process combined with occasional innovations in behavior lead to a process of cultural evolution involving populations of cultural variants. Different local human populations were associated with different local populations of cultural variants, and both the human and the cultural populations evolved over time. Human evolution cannot be understood without taking into account these parallel processes of genetic and cultural evolution. Not by Genes Alone traces the implication of dual-inheritance theory for understanding human evolution and refers to various bodies of evidence relevant to the theory. [ABSTRACT FROM AUTHOR]

Human languages show a remarkable degree of variation in the area they cover. However, the factors governing the distribution of human cultural groups such as languages are not well understood. While previous studies have examined the role of a number of environmental variables the importance of cultural factors has not been systematically addressed. Here we use a geographical information system (GIS) to integrate information about languages with environmental, ecological, and ethnographic data to test a number of hypotheses that have been proposed to explain the global distribution of languages. We show that the degree of political complexity and type of subsistence strategy exhibited by societies are important predictors of the area covered by a language. Political complexity is also strongly associated with the latitudinal gradient in language area, whereas subsistence strategy is not. We argue that a process of cultural group selection favoring more complex societies may have been important in shaping the present-day global distribution of language diversity. [ABSTRACT FROM AUTHOR]

Abstract: This study examines the effects of ingroup favoritism and outgroup hostility (“parochialism”), as well as of conditionally cooperative strategies, in explaining contributions to experimental public goods games. The experimental conditions vary group composition along two culturally inheritable traits (political party preference and religious affiliation) and one trivial, “minimal” trait (birth season). We contrast ingroup, outgroup, and random group conditions and investigate the relation between the own contribution to the public good and the expectations about other group members'' behavior in each one of them. We find evidence for ingroup favoritism but no support for a separate tendency towards outgroup hostility. Further, conditional cooperation and ingroup bias are, to some extent, linked. Subjects had higher expectations of the contributions of ingroup members, and their own behavior was more strongly conditioned on other group members'' expected behavior in the ingroup conditions. In ingroup contexts, subjects displayed a form of “strong reciprocity” by giving more than they expected others to at high expectation levels but less at low expectation levels. Once these interactions are taken into account, we do not find a direct effect of ingroup bias anymore. We discuss these results in the light of theories of cultural group selection and conclude that too much emphasis may have been laid on direct intergroup conflict. Our results suggest that differential cooperativeness, rather than parochialism, may characterize the behavior of individuals in cultural ingroups and outgroups. [Copyright &y& Elsevier]

While human genetic variation is limited due to a bottleneck on the origin of the species ∼200 kya, cultural traits can change more rapidly, and may do so in response to the variation in human habitats. Does cultural diversification simulate a natural experiment in evolution much like biodiversity so that cultural divergences and convergences can be interpreted in terms of the differences and similarities of local environments? Or is cultural diversity simply the result of human behavioral flexibility? Although the majority of cultural data comes from the tips of the hominin phylogeny, anthropologists can follow the example of evolutionary ecologists, who often compare the endpoints of phylogenies when that is all that is available. This article compares 97 contemporary indigenous language communities from around the world, and 24 of their cultural traditions, to help determine whether human cultures and their cultural traits are proportionately dispersed, as predicted by the neutral theory of biodiversity, or whether they show non-proportionalities that could be explained with evolutionary reasoning. [ABSTRACT FROM AUTHOR]

The paper presents a bioeconomics theory of homogeneous middleman groups (HMGs) as adaptive units as well as empirical evidence in the form of a number of historical case studies of HMGs functioning as adaptive units in less-developed economies lacking infrastructure. The evidence presented is not new: most of the case studies have been published [Landa (in Jenkins (Ed.) The informal sector: Including the excluded, 1988)]. What is new, however, is analyzing the phenomena of HMGs in a new way—as adaptive units viewed from a group selection perspective. In doing so, the case studies in this paper present empirical evidence of the existence and importance of group selection in human society. [ABSTRACT FROM AUTHOR]

Abstract: Economists and psychologists have been testing Nash equilibrium predictions of game theory models of human behavior. In many instances, humans do not conform to the predictions. These results are of great interest to biologists because they also raise questions about well-known ESS models of cooperation. Cooperation in certain one-shot, anonymous interactions, and a willingness to punish others at a net cost to oneself are some of the most intriguing deviations from standard theory. One proposed explanation for these results that is receiving increasing attention invokes the cultural group selection of ‘other regarding’ social norms. We critically review this explanation. We conclude that experimental results reveal limits in two implicit models of cognitive structure commonly employed by economists and evolutionary biologists. [Copyright &y& Elsevier]

In focusing on gender differences in anger expression, Trnka (2013) provides a useful complement to the article by Ingram et al., (2012) analyzing gender differences in children's narratives about peer conflict. I agree that gender differences in anger are more likely to be the result of differential socialization processes regarding the expression of anger than by innate differences in the experience of anger. Gender differences in intersexual anger and aggression are likely to be affected by the social context, and especially whether a female is interacting with a romantic partner or an unknown male. The implication of socialization in anger expression raises the possibility that culture plays a causal role in encouraging cooperative breeding by inhibiting inter-female aggressive displays. Another of Trnka's proposals, that the expression of anger contributes to reconciliation and inhibits long-term relationship damage, is intuitively plausible and supported by the research literature, but not by data from the current study. [ABSTRACT FROM AUTHOR]

Cultural group selection has been proposed as an explanation for humans' highly cooperative nature. This theory argues that social learning mechanisms, combined with rewards and punishment, can stabilise any group behaviour, cooperative or not. Equilibrium selection can then operate, resulting in cooperative groups outcompeting less-cooperative groups. This process may explain the widespread cooperation between non-kin observed in humans, which is sometimes claimed to be altruistic. This review explores the assumptions of cultural group selection to assess whether it provides a convincing explanation for human cooperation. Although competition between cultural groups certainly occurs, it is unclear whether this process depends on specific social learning mechanisms (e.g. conformism) or a norm psychology (to indiscriminately punish norm-violators) to stabilise groups at different equilibria as proposed by existing cultural group selection models. Rather than unquestioningly adopt group norms and institutions, individuals and groups appear to evaluate, design and shape them for self-interested reasons (where possible). As individual fitness is frequently tied to group fitness, this often coincides with constructing group-beneficial norms and institutions, especially when groups are in conflict. While culture is a vital component underlying our species' success, the extent to which current conceptions of cultural group selection reflect human cooperative evolution remains unclear., Competing Interests: None., (© The Author(s) 2020.)

Helping is a cornerstone of social organization and commonplace in human societies. A major challenge for the evolutionary sciences is to explain how cooperation is maintained in large populations with high levels of migration, conditions under which cooperators can be exploited by selfish individuals. Cultural group selection models posit that such large-scale cooperation evolves via selection acting on populations among which behavioural variation is maintained by the cultural transmission of cooperative norms. These models assume that individuals acquire cooperative strategies via social learning. This assumption remains empirically untested. Here, I test this by investigating whether individuals employ conformist or payoff-biased learning in public goods games conducted in 14 villages of a forager–horticulturist society, the Pahari Korwa of India. Individuals did not show a clear tendency to conform or to be payoff-biased and are highly variable in their use of social learning. This variation is partly explained by both individual and village characteristics. The tendency to conform decreases and to be payoff-biased increases as the value of the modal contribution increases. These findings suggest that the use of social learning in cooperative dilemmas is contingent on individuals' circumstances and environments, and question the existence of stably transmitted cultural norms of cooperation. [ABSTRACT FROM AUTHOR]

Conceptions of fairness vary across the world. Identifying the drivers of this variation is key to understanding the selection pressures and mechanisms that lead to the evolution of fairness in humans. Individuals' varying fairness preferences are widely assumed to represent cultural norms. However, this assumption has not previously been tested. Fairness norms are defined as culturally transmitted equilibria at which bargainers have coordinated expectations from each other. Hence, if fairness norms exist at the level of the ethno-linguistic group, we should observe two patterns. First, cultural conformism should maintain behavioural homogeneity within an ethno-linguistic group. Second, bargainers' expectations should be coordinated such that proposals and responses to proposals should covary. Here we show that neither of these patterns is observed across 21 populations of the same ethno-linguistic group, the Pahari Korwa of central India. Our findings suggest that what constitutes a fair division of resources can vary on smaller scales than that of the ethno-linguistic group. Individuals' local environments may play a central role in determining conceptions of fairness. [ABSTRACT FROM AUTHOR]