Building the Leviathan--Voluntary centralisation of punishment power sustains cooperation in humans

An outside individual option increases optimism and facilitates collaboration when groups form flexibly

Voluntary participation is a central yet understudied aspect of collaboration. Here, we model collaboration as people's voluntary choices between joining an uncertain public goods provisioning in groups and pursuing a less profitable but certain individual option. First, we find that voluntariness in collaboration increases the likelihood of group success via two pathways, both contributing to form more optimistic groups: pessimistic defectors are filtered out from groups, and some individuals update their beliefs to become cooperative. Second, we reconcile these findings with existing literature that highlights the detrimental effects of an individual option. We argue that the impact of an outside individual option on collaboration depends on the "externality" of loners - the influence that those leaving the group still exert on group endeavors. Theoretically and experimentally, we show that if collaboration allows for flexible group formation, the negative externality of loners remains limited, and the presence of an individual option robustly aids collaborative success.

Discipline and punishment in panoptical public goods games

In Public Goods Games (PGG), the temptation to free-ride on others' contributions poses a significant threat to the sustainability of cooperative societies. Therefore, societies strive to mitigate this through incentive systems, employing rewards and punishments to foster cooperative behavior. Thus, peer punishment, in which cooperators sanction defectors, as well as pool punishment, where a centralized punishment institution executes the punishment, is deeply analyzed in previous works. Although the literature indicates that these methods may enhance cooperation on social dilemmas under particular contexts, there are still open questions, for instance, the structural connection between graduated punishment and the monitoring of public goods games. Our investigation proposes a compulsory PGG framework under Panoptical surveillance. Inspired by Foucault's theories on disciplinary mechanisms and biopower, we present a novel mathematical model that scrutinizes the balance between the severity and scope of punishment to catalyze cooperative behavior. By integrating perspectives from evolutionary game theory and Foucault's theories of power and discipline, this research uncovers the theoretical foundations of mathematical frameworks involved in punishment and discipline structures. We show that well-calibrated punishment and discipline schemes, leveraging the panoptical effect for universal oversight, can effectively mitigate the free-rider dilemma, fostering enhanced cooperation. This interdisciplinary approach not only elucidates the dynamics of cooperation in societal constructs but also underscores the importance of integrating diverse methodologies to address the complexities of fostering cooperative evolution.

Norm violations and punishments across human societies

Punishments for norm violations are hypothesised to be a crucial component of the maintenance of cooperation in humans but are rarely studied from a comparative perspective. We investigated the degree to which punishment systems were correlated with socioecology and cultural history. We took data from the Standard Cross-Cultural Sample database and coded ethnographic documents from a sample of 131 largely non-industrial societies. We recorded whether punishment for norm violations concerned adultery, religion, food, rape or war cowardice and whether sanctions were reputational, physical, material or execution. We used Bayesian phylogenetic regression modelling to test for culture-level covariation. We found little evidence of phylogenetic signals in evidence for punishment types, suggesting that punishment systems change relatively quickly over cultural evolutionary history. We found evidence that reputational punishment was associated with egalitarianism and the absence of food storage; material punishment was associated with the presence of food storage; physical punishment was moderately associated with greater dependence on hunting; and execution punishment was moderately associated with social stratification. Taken together, our results suggest that the role and kind of punishment vary both by the severity of the norm violation, but also by the specific socio-economic system of the society.

Discriminatory punishment undermines the enforcement of group cooperation

Peer punishment can help groups to establish collectively beneficial public goods. However, when humans condition punishment on other factors than poor contribution, punishment can become ineffective and group cooperation deteriorates. Here we show that this happens in pluriform groups where members have different socio-demographic characteristics. In our public good provision experiment, participants were confronted with a public good from which all group members benefitted equally, and in-between rounds they could punish each other. Groups were uniform (members shared the same academic background) or pluriform (half the members shared the same academic background, and the other half shared another background). We show that punishment effectively enforced cooperation in uniform groups where punishment was conditioned on poor contribution. In pluriform groups, punishment was conditioned on poor contribution too, but also partially on others' social-demographic characteristics-dissimilar others were punished more than similar others regardless of their contribution. As a result, punishment lost its effectiveness in deterring free-riding and maintaining public good provision. Follow-up experiments indicated that such discriminatory punishment was used to demarcate and reinforce subgroup boundaries. This work reveals that peer punishment fails to enforce cooperation in groups with a pluriform structure, which is rule rather than exception in contemporary societies.

Oxytocin and the Punitive Hub-Dynamic Spread of Cooperation in Human Social Networks

Human society operates on large-scale cooperation. However, individual differences in cooperativeness and incentives to free ride on others' cooperation make large-scale cooperation fragile and can lead to reduced social welfare. Thus, how individual cooperation spreads through human social networks remains puzzling from ecological, evolutionary, and societal perspectives. Here, we identify oxytocin and costly punishment as biobehavioral mechanisms that facilitate the propagation of cooperation in social networks. In three laboratory experiments (n = 870 human participants: 373 males, 497 females), individuals were embedded in heterogeneous networks and made repeated decisions with feedback in games of trust (n = 342), ultimatum bargaining (n = 324), and prisoner's dilemma with punishment (n = 204). In each heterogeneous network, individuals at central positions (hub nodes) were given intranasal oxytocin (or placebo). Giving oxytocin (vs matching placebo) to central individuals increased their trust and enforcement of cooperation norms. Oxytocin-enhanced norm enforcement, but not elevated trust, explained the spreading of cooperation throughout the social network. Moreover, grounded in evolutionary game theory, we simulated computer agents that interacted in heterogeneous networks with central nodes varying in terms of cooperation and punishment levels. Simulation results confirmed that central cooperators' willingness to punish noncooperation allowed the permeation of the network and enabled the evolution of network cooperation. These results identify an oxytocin-initiated proximate mechanism explaining how individual cooperation facilitates network-wide cooperation in human society and shed light on the widespread phenomenon of heterogeneous composition and enforcement systems at all levels of life.SIGNIFICANCE STATEMENT Human society operates on large-scale cooperation. Yet because cooperation is exploitable by free riding, how cooperation in social networks emerges remains puzzling from evolutionary and societal perspectives. Here we identify oxytocin and altruistic punishment as key factors facilitating the propagation of cooperation in human social networks. Individuals played repeated economic games in heterogeneous networks where individuals at central positions were given oxytocin or placebo. Oxytocin-enhanced cooperative norm enforcement, but not elevated trust, explained cooperation spreading throughout the social network. Evolutionary simulations confirmed that central cooperators' willingness to punish noncooperation allowed the permeation of the network and enabled the evolution of cooperation. These results identify an oxytocin-initiated proximate mechanism explaining how individual cooperation facilitates network-wide cooperation in human social networks.

The Effect of the Quantity and Distribution of Teammates' Tendency Toward Self-Interest and Altruism on Individual Decision-Making

Previous studies have explored the impact of the cost ratio of individual solutions versus collective solutions on people's cooperation tendency in the presence of individual solutions. This study further explored the impact of team credibility on people's propensity to cooperate in the presence of individual solutions. Study 1 investigated the influence of different level of altruistic tendencies or the self-interest tendencies of teammates on participants' decision-making. Study 2 explored the influence of the distribution of altruistic tendencies or self-interest tendencies on participants' decision-making. The results of Study 1 showed that the proportion of participants who chose the collective solution increased with an increase in the altruistic tendencies of the team. When the altruistic tendencies of the teammates reached a certain value, the proportion of participants taking the collective solution showed a trend to stabilize. Furthermore, the proportion of participants who chose the individual solution increased with the increase in the self-interest tendencies of the team. When the self-interest tendencies of the teammates reached a certain value, the individual solution was stably adopted. The results of Study 2 showed that with the total altruistic tendency remaining unchanged, the more altruistic group members that altruistic tendencies were allocated to, the higher a participant's level of trust in the team would be, which showed the decentralized effect of altruistic tendencies. In the case that the total self-interest tendency was unchanged, the fewer self-interest group members the self-interest tendencies were allocated to, the higher a participant's level of trust in the team would be, which showed the convergent effect of self-interest tendencies.

Reward, punishment, and prosocial behavior: Recent developments and implications

Reward and punishment change the payoff structures of social interactions and therefore can potentially play a role in promoting prosocial behavior. Yet, there are boundary conditions for them to be effective. We review recent work that addresses the conditions under which rewards and punishment can enhance prosocial behavior, the proximate and ultimate mechanisms for individuals' rewarding and punishing decisions, and the reputational and behavioral consequences of reward and punishment under noise. The reviewed evidence points to the importance of more field research on how reward and punishment can promote prosocial behavior in real-world settings. We also highlight the need to integrate different methodologies to better examine the effects of reward and punishment on prosocial behavior.

Constructing the Facets of Altruistic Behaviors (FAB) Scale

Abstract. Behavior is effectively altruistic to the degree that it is costly for the actor while benefiting others. In a series of preregistered studies, we constructed a 15-item self-report scale assessing three different facets of altruistic behavioral traits: help-giving, moral courage, and peer punishment. Item selection was performed with the help of Ant Colony Optimization (ACO) procedures as implemented in the stuart package for R. Confirmatory factor analysis of the three-factor measurement model showed excellent fit, outperforming classical item selection procedures. The scale was structure-validated in a second sample using a multiple group model that showed full measurement and structural invariance. A pilot study shows correlations of the subscales with economic game decisions. We discuss the scale structure and potential applications.

Rule Following Mitigates Collaborative Cheating and Facilitates the Spreading of Honesty Within Groups

Compared with working alone, interacting in groups can increase dishonesty and give rise to collaborative cheating-the joint violation of honesty. At the same time, collaborative cheating emerges some but not all of the time, even when dishonesty is not sanctioned and economically rational. Here, we address this conundrum. We show that people differ in their extent to follow arbitrary and costly rules and observe that "rule-followers" behave more honestly than "rule-violators." Because rule-followers also resist the temptation to engage in collaborative cheating, dyads and groups with at least one high rule-follower have fewer instances of coordinated violations of honesty. Whereas social interaction can lead to a "social slippery slope" of increased cheating, rule-abiding individuals mitigate the emergence and spreading of collaborative cheating, leading to a transmission advantage of honesty. Accordingly, interindividual differences in rule following provide a basis through which honest behavior can persist.

Voluntary restrictions on self-reliance increase cooperation and mitigate wealth inequality

Humans are considered a highly cooperative species. Through cooperation, we can tackle shared problems like climate change or pandemics and cater for shared needs like shelter, mobility, or healthcare. However, cooperation invites free-riding and can easily break down. Maybe because of this reason, societies also enable individuals to solve shared problems individually, like in the case of private healthcare plans or private retirement planning. Such "self-reliance" allows individuals to avoid problems related to public goods provision, like free-riding or underprovision, and decreases social interdependence. However, not everyone can equally afford to be self-reliant, and amid shared problems, self-reliance may lead to conflicts within groups on how to solve shared problems. In two preregistered studies, we investigate how the ability of self-reliance influences collective action and cooperation. We show that self-reliance crowds out cooperation and exacerbates inequality, especially when some heavily depend on collective action while others do not. However, we also show that groups are willing to curtail their ability of self-reliance. When given the opportunity, groups overwhelmingly vote in favor of abolishing individual solutions to shared problems, which, in turn, increases cooperation and decreases inequality, particularly between group members that differ in their ability to be self-reliant. The support for such endogenously imposed interdependence, however, reduces when individual solutions become more affordable, resonating with findings of increased individualism in wealthier societies and suggesting a link between wealth inequality and favoring individual independence and freedom over communalism and interdependence.

Self-reliance crowds out group cooperation and increases wealth inequality

Humans establish public goods to provide for shared needs like safety or healthcare. Yet, public goods rely on cooperation which can break down because of free-riding incentives. Previous research extensively investigated how groups solve this free-rider problem but ignored another challenge to public goods provision. Namely, some individuals do not need public goods to solve the problems they share with others. We investigate how such self-reliance influences cooperation by confronting groups in a laboratory experiment with a safety problem that could be solved either cooperatively or individually. We show that self-reliance leads to a decline in cooperation. Moreover, asymmetries in self-reliance undermine social welfare and increase wealth inequality between group members. Less dependent group members often choose to solve the shared problem individually, while more dependent members frequently fail to solve the problem, leaving them increasingly poor. While self-reliance circumvents the free-rider problem, it complicates the governing of the commons.

Cooperation among humans is threatened by the free-rider problem. Here the authors identify another challenge to human cooperation: self-reliance, the ability to solve shared problems individually. The experiment reveals that self-reliance crowds out cooperation and increases wealth inequality.

The role of peer reward and punishment for public goods problems in a localized society

Cooperation in social dilemmas can be sustained if individuals are effectively rewarded or punished from peers within the group. However, as group size increases, we inevitably face localization, in which a global group is divided into several localized groups. In such societies, members can reward and punish only neighbors within the same localized group, while cooperation for social dilemmas should be solved through global group involvement. In this situation, the global group and the local group are not always equal in terms of welfare, and situations can arise in which cooperation is beneficial for the global group but not for the local group. We predict that in such a locally inefficient situation, peer reward and punishment cannot function to sustain global cooperation. We conducted an experiment in which 16 group members played a public goods game incorporating peer reward and punishment. We manipulated the range of peer reward and punishment (only local members/all global members) and payoff structure (locally efficient/locally inefficient). We found that high cooperation was not achieved and that peer reward and punishment did not function when, and only when, the group was divided into localized groups and the payoff structure was locally inefficient.

Punishment: one tool, many uses

Humans are outstanding in their ability to cooperate with unrelated individuals, and punishment - paying a cost to harm others - is thought to be a key supporting mechanism. According to this view, cooperators punish defectors, who respond by behaving more cooperatively in future interactions. However, a synthesis of the evidence from laboratory and real-world settings casts serious doubts on the assumption that the sole function of punishment is to convert cheating individuals into cooperators. Instead, punishment often prompts retaliation and punishment decisions frequently stem from competitive, rather than deterrent motives. Punishment decisions often reflect the desire to equalise or elevate payoffs relative to targets, rather than the desire to enact revenge for harm received or to deter cheats from reoffending in future. We therefore suggest that punishment also serves a competitive function, where what looks like spiteful behaviour actually allows punishers to equalise or elevate their own payoffs and/or status relative to targets independently of any change in the target's behaviour. Institutions that reduce or remove the possibility that punishers are motivated by relative payoff or status concerns might offer a way to harness these competitive motives and render punishment more effective at restoring cooperation.

Infants expect leaders to right wrongs

Anthropological and psychological research on direct third-party punishment suggests that adults expect the leaders of social groups to intervene in within-group transgressions. Here, we explored the developmental roots of this expectation. In violation-of-expectation experiments, we asked whether 17-mo-old infants (n = 120) would expect a leader to intervene when observing a within-group fairness transgression but would hold no particular expectation for intervention when a nonleader observed the same transgression. Infants watched a group of 3 bear puppets who served as the protagonist, wrongdoer, and victim. The protagonist brought in 2 toys for the other bears to share, but the wrongdoer seized both toys, leaving none for the victim. The protagonist then either took 1 toy away from the wrongdoer and gave it to the victim (intervention event) or approached each bear in turn without redistributing a toy (nonintervention event). Across conditions, the protagonist was either a leader (leader condition) or a nonleader equal in rank to the other bears (nonleader condition); across experiments, leadership was marked by either behavioral or physical cues. In both experiments, infants in the leader condition looked significantly longer if shown the nonintervention as opposed to the intervention event, suggesting that they expected the leader to intervene and rectify the wrongdoer's transgression. In contrast, infants in the nonleader condition looked equally at the events, suggesting that they held no particular expectation for intervention from the nonleader. By the second year of life, infants thus already ascribe unique responsibilities to leaders, including that of righting wrongs.

Power in economic games

Economic games offer an analytic tool to examine strategic decision-making in social interactions. Here we identify four sources of power that can be captured and studied with economic games - asymmetric dependence, the possibility to reduce dependence, the ability to punish and reward, and the use of knowledge and information. We review recent studies examining these distinct forms of power, highlight that the use of economic games can benefit our understanding of the behavioral and neurobiological underpinnings of power, and illustrate how power differences within and between groups impact cooperation, exploitation, and conflict.

Individual solutions to shared problems create a modern tragedy of the commons

Alone and together, climatic changes, population growth, and economic scarcity create shared problems that can be tackled effectively through cooperation and coordination. Perhaps because cooperation is fragile and easily breaks down, societies also provide individual solutions to shared problems, such as privatized healthcare or retirement planning. But how does the availability of individual solutions affect free-riding and the efficient creation of public goods? We confronted groups of individuals with a shared problem that could be solved either individually or collectively. Across different cost-benefit ratios of individually versus collectively solving the shared problem, individuals display a remarkable tendency toward group-independent, individual solutions. This "individualism" leads to inefficient resource allocations and coordination failure. Introducing peer punishment further results in wasteful punishment feuds between "individualists" and "collectivists." In the presence of individual solutions to shared problems, groups struggle to balance self-reliance and collective efficiency, leading to a "modern tragedy of the commons."

Low-cost, high-impact altruistic punishment promotes cooperation cascades in human social networks

Theoretical models and experiments suggest that social networks may significantly impact the emergence and stability of cooperation in humans. Similarly, theoretical models and experiments have shown that punishing behavior can significantly increase cooperative behavior in individuals. However, how punishing impacts the effects of social networks on cooperation is not yet understood. Here, I examine a set of laboratory experiments in which participants choose to cooperate or defect under differing punishment arrangements. Through analysis of the experiment as a network, I evaluate how institutional arrangements affect the degree to which social networks promote cooperative behavior. The results show that cooperative behavior spreads from person-to-person in all versions of the game, but that in versions of the game with low-cost, high-impact punishment the influence both endures for more rounds and spreads further in the network. These results show that the extent to which cooperative behavior cascades is affected by the institutional arrangements that govern game play.

Solidarity through punishment: An experiment on the merits of centralized enforcement in generalized exchange

Solidarity and punishment are both central to maintaining social order, but their interaction remains poorly understood. A number of studies report that punishment undermines solidarity in domains of generalized exchange, whereas other studies find that punishment furthers norm-compliant behavior and thereby promotes solidarity in the realm of public goods. Using a laboratory experiment, this study is the first to directly compare the effect of centralized punishment on solidarity between generalized exchange and public good settings. The results reveal that it is generalized exchange where centralized punishment induces solidarity, whereas in the public good setting the effect of punishment is negligible. The paper concludes that the structure of generalized exchange alone is insufficient to induce solidarity. In addition, generalized exchange systems require external stabilization, as provided by centralized punishment.

Ethical Free Riding: When Honest People Find Dishonest Partners

Corruption is often the product of coordinated rule violations. Here, we investigated how such corrupt collaboration emerges and spreads when people can choose their partners versus when they cannot. Participants were assigned a partner and could increase their payoff by coordinated lying. After several interactions, they were either free to choose whether to stay with or switch their partner or forced to stay with or switch their partner. Results reveal that both dishonest and honest people exploit the freedom to choose a partner. Dishonest people seek a partner who will also lie—a “partner in crime.” Honest people, by contrast, engage in ethical free riding: They refrain from lying but also from leaving dishonest partners, taking advantage of their partners’ lies. We conclude that to curb collaborative corruption, relying on people’s honesty is insufficient. Encouraging honest individuals not to engage in ethical free riding is essential.

Solving the second-order free rider problem in a public goods game: An experiment using a leader support system

Punishment of non-cooperators-free riders-can lead to high cooperation in public goods games (PGG). However, second-order free riders, who do not pay punishment costs, reduce the effectiveness of punishment. Here we introduce a "leader support system," in which one group leader can freely punish group followers using capital pooled through the support of group followers. In our experiment, participants engage in three stages repeatedly: a PGG stage in which followers decide to cooperate for their group; a support stage in which followers decide whether to support the leader; and a punishment stage in which the leader can punish any follower. We compare a support-present condition with a no-support condition, in which there is an external source for the leader's punishment. The results show that punishment occurs more frequently in the support-present condition than the no-support condition. Within the former, both higher cooperation and higher support for a leader are achieved under linkage-type leaders-who punish both non-cooperators and non-supporters. In addition, linkage-type leaders themselves earn higher profits than other leader types because they withdraw more support. This means that leaders who effectively punish followers could increase their own benefits and the second-order free rider problem would be solved.

In-group defense, out-group aggression, and coordination failures in intergroup conflict

Intergroup conflict persists when and because individuals make costly contributions to their group's fighting capacity, but how groups organize contributions into effective collective action remains poorly understood. Here we distinguish between contributions aimed at subordinating out-groups (out-group aggression) from those aimed at defending the in-group against possible out-group aggression (in-group defense). We conducted two experiments in which three-person aggressor groups confronted three-person defender groups in a multiround contest game (n = 276; 92 aggressor-defender contests). Individuals received an endowment from which they could contribute to their group's fighting capacity. Contributions were always wasted, but when the aggressor group's fighting capacity exceeded that of the defender group, the aggressor group acquired the defender group's remaining resources (otherwise, individuals on both sides were left with the remainders of their endowment). In-group defense appeared stronger and better coordinated than out-group aggression, and defender groups survived roughly 70% of the attacks. This low success rate for aggressor groups mirrored that of group-hunting predators such as wolves and chimpanzees (n = 1,382 cases), hostile takeovers in industry (n = 1,637 cases), and interstate conflicts (n = 2,586). Furthermore, whereas peer punishment increased out-group aggression more than in-group defense without affecting success rates (Exp. 1), sequential (vs. simultaneous) decision-making increased coordination of collective action for out-group aggression, doubling the aggressor's success rate (Exp. 2). The relatively high success rate of in-group defense suggests evolutionary and cultural pressures may have favored capacities for cooperation and coordination when the group goal is to defend, rather than to expand, dominate, and exploit.

Who Punishes? The Status of the Punishers Affects the Perceived Success of, and Indirect Benefits From, “Moralistic” Punishment

“Moralistic” punishment of free riders can provide a beneficial reputation, but the immediate behavior is costly to the punisher. In Study 1, we investigated whether variation in status would be perceived to offset or mitigate the costs of punishment. One hundred and nineteen participants were presented with a vignette describing a punishment scenario. Participants predicted whether punishment would occur, how successful it would be, and indicated their attitude to the punisher. Participants believed only intervention by a high-status (HS) individual would be successful and that low-status (LS) individuals would not intervene at all. HS individuals predicted to punish successfully were seen as more formidable and likable. Study 2 investigated whether punishment was necessary to maintain an HS position. One hundred and seventeen participants were presented with a vignette describing a punishment scenario. Participants were asked to indicate whether they wished to be led by the punisher. HS individuals who did not punish were less likely to be chosen as leaders compared to HS punishers, whereas LS individuals who punished were no more or less likely to be chosen than nonpunishers. The results of both studies suggest that only HS individuals are expected to punish, likely because such a position offsets some of the costs of punishment. As a result, only HS individual can access the reputation benefits from punishment. Furthermore, an HS position may be dependent on the willingness to punish antisocial behavior. The ramifications that these results may have for the evolution of moralistic punishment are discussed.