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This paper introduces a stochastic strategy updating rule with preference in the public goods game. Besides, we also consider the carrying capacity of individual reproductive abilities and two different types of population sizes, the fluctuating and fixed sizes. Through systematic analyses, this paper explores the impact of the preference heterogeneity in the stochastic strategy update rule on the emergence and maintenance of cooperation. The results show that in both types of populations, the strategy updating rule can facilitate the evolution of cooperation by increasing the preference for cooperation, thereby alleviating the public goods dilemma. In addition, in a fixed-size population, when cooperation is a successful evolutionary strategy, increasing the preference for cooperation is beneficial to enhancing the maintenance of the cooperation. However, in a fluctuating-size finite population, reducing the preference for cooperation is beneficial to enhancing the stability of the cooperative evolutionary dynamics. [ABSTRACT FROM AUTHOR]

Social mindfulness and Zhongyong thinking style are of high importance when evaluating relevant co‐actors in the social world. The current study investigates the influence of social mindfulness and Zhongyong thinking style on cooperative financial decision making in a public goods game among a Canadian sample. We hypothesize that higher perceived social mindfulness and higher perceived Zhongyong thinking style will increase the amount of money contributed to a joint project in a public goods game. The sample was a prolific‐based online recruited sample of n = 125 Canadians. We observed a significant main effect of Zhongyong thinking style on the amount of contributed money in the public goods game. Social mindfulness did not reach significance. The influence of Zhongyong thinking style was qualified by a significant Zhongyong by gender interaction, indicating that females but not males reduced their contributions if the Zhongyong thinking style of the co‐actor was manipulated as being low. It is shown that Zhongyong thinking style is also relevant in a Western cultural setting. Future research is needed, however, to investigate further the reasons for the differences between females and males. [ABSTRACT FROM AUTHOR]

Does self‐governance, a hallmark of democratic societies, foster norms of generalized cooperation? Does this effect persist, and if so, why? I investigate these questions using a natural experiment in Switzerland. In the Middle Ages, the absence of an heir resulted in the extinction of a prominent noble dynasty. As a result, some Swiss municipalities became self‐governing, whereas the others remained under feudalism for another 600 years. Evidence from a behavioral experiment, the World Values Survey and the Swiss Household Panel consistently show that individuals from historically self‐governing municipalities exhibit stronger norms of cooperation today. Referenda data on voter‐turnout allow me to trace these effects on individually costly and socially beneficial actions for over 150 years. Furthermore, norms of cooperation map into prosocial behaviors like charitable giving and environmental protection. Uniquely, Switzerland tracks every family's place of origin in registration data, which I use to demonstrate persistence from cultural transmission in a context of historically low migration. [ABSTRACT FROM AUTHOR]

Most social scientists agree that informal norms constrain available equilibria in most human interactions. However, they do not agree on how to model them: economists often make them derivative of individual preferences, while a broader tradition in social theory understands them as exogenous social facts. Non-cooperative game theory more naturally accommodates the economists’ approach. However, attention is increasingly attracted to recent work by economists who appreciate that the broader understanding may be important for full empirical adequacy. We focus on how game theorists might track this emerging shift. Extending Stirling’s previously developed Conditional Game Theory, we model macrostructural processes of norm evolution through social influence diffusion in a way that relies on no exotic solution concepts, which in turn allows norms as social facts and norms as expressions of preferences to be modeled as evaluable complements, by analogy to the complementarity of cooperative and non-cooperative game solutions under the Nash program. The result can be understood as a way of specifying mutual constraints between economic models in which normative attitudes are exogenous, and sociological models that represent such attitudes as endogenous under power relationships and ontologies of social roles.

Despite the growing interest in leadership in the experimental literature, theoretical analyses of leadership have received relatively limited attention. This study investigates the effectiveness of leading by example in public goods games among reciprocal agents. The "leading-by-example" game (LBE) is a two-stage game with the same payoff structure as the classic voluntary contribution mechanism (VCM), in which a leader first makes a contribution decision, followed by the followers who make a contribution decision upon observing the leader's move. If the marginal per capita return (MPCR) is sufficiently high, LBE is more effective than VCM at inducing contributions. However, if MPCR is low, VCM is more effective than LBE. An experimental test of the comparative statics is conducted. [ABSTRACT FROM AUTHOR]

Cooperation is essential for the survival of human society. Understanding the nature of cooperation and its underlying mechanisms is crucial for studying human behavior. This paper investigates the impact of leadership on public cooperation by employing repeated sequential public goods games, as well as by examining whether leading by example (through rewards and punishments) can promote cooperation and organizational success. The leaders were assigned randomly and were given the authority to reward or punish. As a result, (1) the leaders showed a strong tendency toward reciprocity by punishing free riders and rewarding cooperators at their own expense, which enhanced the intrinsic motivation for others to follow their example; and (2) both rewards and punishments were effective in promoting cooperation, but punishment was more effective in sustaining a high level of collaboration. Additionally, leaders preferred using rewards and were more reluctant to use punishments. These findings are crucial for creating organizational structures that foster cooperation. [ABSTRACT FROM AUTHOR]

Can purely behavioral aspects affect voluntary cooperativeness in isomorphic social dilemma games? We experimentally test isomorphic invariance by comparing frames whose identical payoffs are described as of the Prisoners' Dilemma or the linear Public Good. Participants play two consecutive rounds of the same frame, with no between-round feedback information, interacting with either the same or a different number of other subjects in each round. Hence, frames are compared between subjects whereas games with different numerosity are compared both within subjects and between subjects. Our analysis rejects isomorphic invariance and shows significantly lower average cooperativeness in the linear Public Good frame across all conditions. Moreover, we find a significantly negative effect of group size, especially in Prisoners' Dilemma. • Experimental test of behavioral validity of isomorphic invariance between PD and PG. • The PG frame reduces cooperativeness and expectations about others' cooperativeness. • Group size negatively influences cooperativeness, particularly in the context of PD. • Effects of task repetition suggest further analysis of incentives in social dilemmas. [ABSTRACT FROM AUTHOR]

With the advancement of Internet technology and social network, a multitude of real-world issues can be modeled as combinatorial optimization problems on networks, attracting widespread attention. In the optimization process, agents often engage in strategic behavior driven by personal interests to maximize their utilities. This "selfish" behavior can, on one hand, affect other participants, while on the other hand, the strategies of all agents directly determine the achievement of societal objectives. Therefore, cooperation and competition coexist among participants, giving rise to combinatorial optimization games. This paper aims to delve into three challenging combinatorial optimization games on networks: public goods games, vertex cover games, and routing games. These three categories of games not only hold significant positions in the fields of combinatorial optimization and theoretical computer science, but also have extensive applications across multiple interdisciplinary areas including management science and engineering, economics, and more. To this end, we will provide a systematic introduction to these three types of combinatorial optimization games and thoroughly review their recent research progress and breakthroughs. [ABSTRACT FROM AUTHOR]

Play is phylogenetically widespread, and there are many proposed theories and fitness benefits of play. However, we still need a theoretical framework that unifies our understanding of the benefits that facilitated the evolution of play in so many diverse species. Starting with von Uexküll's theory of the Umwelt (i.e., the sensory-motor worlds of animals), together with the behavior systems approach, we propose that the Umwelt is an information processing system that serves basic biological functions. During development, the Umwelt undergoes a rapid expansion in the sensory and motor stimuli it processes. We argue that play is a process that converts surplus resources into information. By increasing the information content of the developing Umwelt, play confers fitness benefits. To demonstrate that play could evolve based on its information benefits, we present a model and simulation results of the evolution of a social play learning process that provides fitness-enhancing information in adult cooperative and competitive situations. Finally, we discuss this information-theoretic framework in relation to proposed hypotheses and fitness benefits of play.

Prosocial behavior is crucial for the smooth functioning of the society. Yet, individuals differ vastly in the propensity to behave prosocially. Here, we try to explain these individual differences under normal sleep conditions without any experimental modulation of sleep. Using a portable high-density EEG, we measured the sleep data in 54 healthy adults (28 females) during a normal night's sleep at the participants' homes. To capture prosocial preferences, participants played an incentivized public goods game in which they faced real monetary consequences. The whole-brain analyses showed that a higher relative slow-wave activity (SWA, an indicator of sleep depth) in a cluster of electrodes over the right temporoparietal junction (TPJ) was associated with increased prosocial preferences. Source localization and current source density analyses further support these findings. Recent sleep deprivation studies imply that sleeping enough makes us more prosocial; the present findings suggest that it is not only sleep duration, but particularly sufficient sleep depth in the TPJ that is positively related to prosociality. Because the TPJ plays a central role in social cognitive functions, we speculate that sleep depth in the TPJ, as reflected by relative SWA, might serve as a dispositional indicator of social cognition ability, which is reflected in prosocial preferences. These findings contribute to the emerging framework explaining the link between sleep and prosocial behavior by shedding light on the underlying mechanisms. [ABSTRACT FROM AUTHOR]

Some scholars find that behavioral variation in the public goods game is explained by variations in participants' understanding of how to maximize payoff and that confusion leads to cooperation. Their findings lead them to question the common assumption in behavioral economics experiments that choices reflect motivations. We conduct two experiments, in which we minimize confusion by providing participants with increased training. We also introduce a question that specifically assesses participants' understanding of payoff maximization choices. Our experimental results show that the distribution of behavior types is significantly different when participants play with computers versus humans. A significant increase in contributions is also observed when participants play with humans compared to when they play with computers. Moreover, social norms may be the main motive for contributions when playing with computers. Our findings suggest that social preferences, rather than confusion, play a crucial role in determining contributions in public goods games when playing with humans. We therefore argue that the assumption in behavioral economics experiments that choices reveal motivations is indeed valid. [ABSTRACT FROM AUTHOR]

Theoretical models suggest a relationship between cooperation and the prime numbers. In environments where agents play multiple one-shot prisoner’s dilemma games per generation, cooperators evolve to fixation more frequently when cooperating on a cyclical schedule with a prime-number period length. This finding parrots classic predator–prey models showing selection for prime-number prey life cycles. Here, I report an empirical test of the former models using previously published data concerning humans playing one-shot public goods games across multiple time points—i.e. an analogue to multiple one-shot prisoner’s dilemma games. I find very modest evidence of cyclicality at prime-numbered time intervals, though results indicate rough agreement between theoretical predictions and observed rates of full cooperation across time points. Analyses of individual decisions find increased contributions to the public good at prime-number time points and separate placebo tests indicate a 4-in-1000 chance of spuriously estimating this effect. However, when exploratory analyses exclude low-value prime-numbered time points, the magnitude of the estimated effect decreases and the hypothesis of no effect cannot be rejected, implying that low-value, prime-number time points drive estimates, contrary to theoretical model predictions. These findings cast doubt on the hypothesis of increased cooperation at prime-number time points—at least among humans playing public goods games.

Abstract It has been proved that cognitive biases widely exist in various social realities and lead to unprecedented consequences by affecting individual judgment and decision-making processes in distinct ways. To further explore the influence of changeable cognitive bias, we introduce a heterogeneous population and learning process that can be influenced by cognitive bias into the threshold public goods game (TPGG). Specifically, additional parameters describing the heterogeneity and updating speed of bias are employed. The combined effects of bias and the inherent parameters in the TPGG model on the evolution of cooperation are explored. Numerical simulation results show that the heterogeneity of cognitive bias exhibits diametrically opposite effects when the threshold is relatively low and high, and the effect of incentives based on fixed reward and adjustable punishment are distorted by heterogeneous cognitive biases as well. In addition, the process of social learning forces individuals to update their beliefs toward the direction of obtaining a higher payoff. Different learning rates eventually lead to distinct levels of cooperation by changing the distribution of cognitive bias when the population reaches the evolutionary steady state. Our work extends the research framework on cognitive bias from the perspective of population heterogeneity and explores the impact of individuals' learning ability on personal bias and cooperative behavior.

How to effectively maintain costly intra-group cooperation has always been a topic of great concern in society. As we all know, inter-group competition is a constructive way to promote intra-group cooperation. Previous inter-group competition mechanisms are primarily based on the total contribution value of all individuals in the group in the current round, which ignore the historical behavior of the group and its members. For comparison, we argue that the introduction of collective reputation which reflects not only the total contribution of the groups in the current round but also the group's historical behavior is necessary for the construction of an inter-group competition model. Furthermore, an excellent collective reputation can help the group obtain more high-quality resources and help the group stand out from the competition. To this end, we introduce a new mechanism of inter-group transfer payment driven by collective reputation and construct a public goods game (PGG) model of inter-group competition to study the dynamic behavior of intra-group cooperation evolution. Two parameters, the proportion of accepted groups a and the proportion of transferred groups b , are introduced. The simulation results suggest that the effectiveness of this model in promoting cooperation depends largely on the joint settings of a and b. And in most cases, the combination of small a and medium b plays the significant role. [ABSTRACT FROM AUTHOR]

It has been proved that cognitive biases widely exist in various social realities and lead to unprecedented consequences by affecting individual judgment and decision-making processes in distinct ways. To further explore the influence of changeable cognitive bias, we introduce a heterogeneous population and learning process that can be influenced by cognitive bias into the threshold public goods game (TPGG). Specifically, additional parameters describing the heterogeneity and updating speed of bias are employed. The combined effects of bias and the inherent parameters in the TPGG model on the evolution of cooperation are explored. Numerical simulation results show that the heterogeneity of cognitive bias exhibits diametrically opposite effects when the threshold is relatively low and high, and the effect of incentives based on fixed reward and adjustable punishment are distorted by heterogeneous cognitive biases as well. In addition, the process of social learning forces individuals to update their beliefs toward the direction of obtaining a higher payoff. Different learning rates eventually lead to distinct levels of cooperation by changing the distribution of cognitive bias when the population reaches the evolutionary steady state. Our work extends the research framework on cognitive bias from the perspective of population heterogeneity and explores the impact of individuals' learning ability on personal bias and cooperative behavior. [ABSTRACT FROM AUTHOR]

Punishment promotes cooperation among selfish agents. Unlike previous studies, we propose a new supervision (heterogeneous preference supervision, HPS) mechanism based on the original random supervision (ORS) mechanism considering regulators' limited supervision ability and agents' heterogeneous preferences. The concepts of exemption list capacity, observation period, and removal time are introduced as the variables under the HPS mechanism. A public goods game model is built to verify the supervision effects under the ORS and HPS mechanisms. The simulation results show that the HPS mechanism can promote cooperation more than the ORS mechanism. Increasing the exemption list capacity can make regulators pay more attention to defectors and improve the cooperation level. Setting a relatively moderate observation period benefits a better supervision effect, while a too-small or too-large observation period leads to the collapse of cooperation. Shortening the removal time can increase the updating speed of the exemption list and enhance the role of the exemption list, resulting in improving the fraction of cooperators. [ABSTRACT FROM AUTHOR]

Purpose The theory of third order inference is a theory of how cultural beliefs influence individuals' decisions under conditions of interdependence and uncertainty. In this study, I build on prior work extending the theory to the role of third order information on social trust in public goods dilemmas. Namely, I argue that when second order information on the beliefs of those relevant to the group task are present, this information should influence decision-making over first and third order. Methodology I test this argument in an experimental public goods game. After measuring first order social trust, participants are randomly sorted into one of four conditions-two that pair third and second order information on social trust as parallel and two that pair them as in conflict. Findings The results suggest that in the presence of second order information on social trust, third order information doesn't have an effect on cooperation. Originality The study extends the theory of third order inference to understanding the role of social trust at the first, second, and third levels in public goods dilemmas. It puts second order information in competition with third order in predicting cooperation. It suggests that resolving the uncertainty over the second order beliefs of a collective is key to preventing inefficient equilibriums when second and third order beliefs conflict. [ABSTRACT FROM AUTHOR]

Cooperation is essential for the survival of human society. Understanding the nature of cooperation and its underlying mechanisms is crucial for studying human behavior. This paper investigates the impact of leadership on public cooperation by employing repeated sequential public goods games, as well as by examining whether leading by example (through rewards and punishments) can promote cooperation and organizational success. The leaders were assigned randomly and were given the authority to reward or punish. As a result, (1) the leaders showed a strong tendency toward reciprocity by punishing free riders and rewarding cooperators at their own expense, which enhanced the intrinsic motivation for others to follow their example; and (2) both rewards and punishments were effective in promoting cooperation, but punishment was more effective in sustaining a high level of collaboration. Additionally, leaders preferred using rewards and were more reluctant to use punishments. These findings are crucial for creating organizational structures that foster cooperation.

In this study we tested whether economic inequality and democratic choices affected individuals' cooperative behavior. We expected two main effects: First one of inequality on cooperation and another of democratic choice on cooperation. We used the public goods game (N = 479), in which participants were given a certain number of tokens and decided how many they wanted to keep in their private fund and how many they wanted to share in the public goods. To manipulate economic inequality, we distributed participants’ initial tokens either equally, unequally or very unequally. To manipulation democratic choice, we presented a prescriptive norm to punish the free-riders, either chosen by the participants or imposed. Cooperative behavior was measured by the number of tokens that participants invested in the public goods ark. A mix design was used, including one between participants manipulated factor (democratic choice) and another one manipulated within participants (inequality distribution). As predicted, our findings showed a significant difference between the high and the low inequality condition on cooperative behavior. Participants cooperate with more tokens in the low (vs. high) inequality condition. However, when the prescriptive norm was introduced, this difference between inequality conditions disappeared. No differences in cooperation were found when the prescriptive norm was either democratically voted or imposed. Our findings showed evidence about the reduction of cooperation in unequal contexts. Additionally, prescriptive norms could reduce differences in cooperative behavior independently of inequality levels. The results show that the study of prescriptive norms could contribute to foment redistribution and tax compliance.

Various regions often adopt punish strategies to solve traffic congestion problems. Punishing defectors is an effective strategy to solve the first-order free-rider problem in a public goods game. But this behavior is costly because the punisher is often also involved in the original joint venture and therefore vulnerable, which jeopardizes the effectiveness of this incentive. As an option, we could hire special players whose sole duty would be to monitor the population and punish defectors. The fines collected by various regions will also be used to subsidize the construction of public transportation. Thereby, we derive inspiration, and propose an improved public goods game model based on bonus and mercenary punishment. Research has shown that after cooperator gives the punisher an appropriate bonus, cooperators can strengthen the punisher, thereby weakening the defector's advantage and indirectly promoting cooperation by stabilizing the punisher's position in the system. In addition, the mechanism of reusing the fines collected from defectors and then subsidize to other players in the system can directly promote the emergence of cooperation.

Many mechanisms behind the evolution of cooperation, such as reciprocity, indirect reciprocity, and altruistic punishment, require group knowledge of individual actions. But what keeps people cooperating when no one is looking? Conformist norm internalization, the tendency to abide by the behavior of the majority of the group, even when it is individually harmful, could be the answer. In this paper, we analyze a world where (1) there is group selection and punishment by indirect reciprocity, but (2) many actions (half) go unobserved and therefore unpunished. Can norm internalization fill this "observation gap" and lead to high levels of cooperation, even when agents may in principle cooperate only when likely to be caught and punished? Specifically, we seek to understand whether adding norm internalization to the strategy space in a public goods game can lead to higher levels of cooperation when both norm internalization and cooperation start out rare. We found the answer to be positive, but, interestingly, not because norm internalizers end up making up a substantial fraction of the population, nor because they cooperate much more than other agent types. Instead, norm internalizers, by polarizing, catalyzing, and stabilizing cooperation, can increase levels of cooperation of other agent types, while only making up a minority of the population themselves. Significance statement: What keeps people cooperating when no one is looking? Group selection favoring cooperative groups does not require observers, but often works best when there is some other norm enforcement mechanism to supplement it. But most norm enforcement mechanisms require observers in order to function. Here, we examine whether norm internalization could fill this enforcement gap, by acting as an "internal enforcer" of norms. Perhaps surprisingly, we discovered in our simulations that the population of norm internalizers always remained quite small, and norm internalizers did not necessarily cooperate more than other agent types. Nevertheless, under certain conditions, they were able to spark significantly higher mean levels of cooperation, by causing other agents to cooperate more—partly by setting off bouts of high cooperation after periods of very low cooperation, and partly by helping maintain those bouts of high cooperation for longer. [ABSTRACT FROM AUTHOR]

Abstract Community‐based conservation is a widely adopted wildlife governance approach, but questions remain about the conditions under which this form of wildlife governance achieves success. Particularly, participating communities are often marked by considerable wealth and risk heterogeneities that are driven by differences in livestock or agricultural holdings and varying exposure to wildlife depredation of those holdings. The effect of these types of heterogeneity on successful conservation collective action is understudied, particularly in the case of risk heterogeneity. This lacuna limits policymakers' ability to effectively match the design of community‐based programs to their particular settings. Using established behavioural experimental techniques, we model the incentive structures underlying community‐based wildlife conservation where actors differ in wealth and exposure to human–wildlife conflict. We conduct a modified binary linear voluntary contribution mechanism game, in which we vary subject endowments and risk of incurring a loss when participating in collective action and we find that the type of heterogeneity matters to collective action success. On their own, the presence of either economic or risk heterogeneities (but not both) dampen cooperation compared with homogeneous groups, as do ‘balanced’ distributions of both heterogeneities (where individuals facing high risk levels receive high endowments and vice versa). However, groups with ‘unbalanced’ heterogeneities (where those facing high risk levels receive low endowments and vice versa) demonstrate cooperation at similar levels to that of homogeneous groups. At the individual level, risk drives cooperative behaviour, although its impact is influenced by relative wealth levels when both forms of heterogeneity are present. These findings suggest the need for a more in‐depth look at the role and interaction of risk and wealth heterogeneities in conservation management. Read the free Plain Language Summary for this article on the Journal blog.

This paper provides novel evidence for links between historic farming practices and current norms of cooperative behaviour. We hypothesise that the cooperation required in wetland rice farming gives rise to strong cultural norms of cooperativeness. We compare participants from prefecture cities that predominately practice wetland rice cultivation to those from non-rice regions. A public goods game with and without punishment is the main measure for cooperative behaviour. Results indicate a strong and robust positive effect of wetland rice farming on cooperative behaviour and pro-social punishment. Complementary, consistent evidence from a natural field experiment and a survey further enriches our data. [ABSTRACT FROM AUTHOR]

With a linear public goods game played in six different variants, this article studies two channels that might moderate social dilemmas and increase cooperation without using pecuniary incentives: moral framing and shaming. We find that cooperation is increased when noncontributing to a public good is framed as morally debatable and socially harmful tax avoidance, while the mere description of a tax context has no effect. However, without social sanctions in place, cooperation quickly deteriorates due to social contagion. We find 'shaming' free-riders by disclosing their misdemeanor to act as a strong social sanction, irrespective of the context in which it is applied. Moralizing tax avoidance significantly reinforces shaming, compared with a simple tax context. [ABSTRACT FROM AUTHOR]

We study experimentally cooperation in group contests under a new sharing rule that captures elements of coopetitive setups that are often characterized by the tension between cooperation and competition. It introduces an allocation of the obtained prize which is inversely proportional to individual efforts. We use it to study if the pervasive over-expenditure observed in group contests remains even when individual effort is extremely disincentivized and compare its effects with the egalitarian sharing rule. Participants in our experiment make more effort with the egalitarian than with the inverse proportional rule, but we document a sizeable over-expenditure even with the inverse proportional rule. We find that contribution in a public goods game is positively associated with effort in the group contest. Social value orientation, risk attitudes, competitiveness, or other personality traits do not predict behavior consistently. [ABSTRACT FROM AUTHOR]

Past experiments show systematic differences in contributions to public goods under various framing conditions. Several explanations of these differences have been presented. Some suggest that social frames affect subjects' preferences, while others suggest that framing changes subjects' beliefs about others, and thus in turn affects behavior. In this paper, we test the effect of framing on the level of contributions in a series of public goods games designed to separate the impact of preferences from beliefs in shaping cooperative decisions. This is achieved by implementing a social value orientation measure to elicit social preferences from decision makers, which are then analyzed in concert with reported beliefs about others' cooperation and own contribution decisions from the linear public goods games. While we find mixed results on framing effects, our study demonstrates that preferences and beliefs are significant predictors of cooperation. Furthermore, the degree to which they influence cooperation is either strengthened or weakened by framing. [ABSTRACT FROM AUTHOR]

Community‐based conservation is a widely adopted wildlife governance approach, but questions remain about the conditions under which this form of wildlife governance achieves success. Particularly, participating communities are often marked by considerable wealth and risk heterogeneities that are driven by differences in livestock or agricultural holdings and varying exposure to wildlife depredation of those holdings.The effect of these types of heterogeneity on successful conservation collective action is understudied, particularly in the case of risk heterogeneity. This lacuna limits policymakers' ability to effectively match the design of community‐based programs to their particular settings.Using established behavioural experimental techniques, we model the incentive structures underlying community‐based wildlife conservation where actors differ in wealth and exposure to human–wildlife conflict. We conduct a modified binary linear voluntary contribution mechanism game, in which we vary subject endowments and risk of incurring a loss when participating in collective action and we find that the type of heterogeneity matters to collective action success.On their own, the presence of either economic or risk heterogeneities (but not both) dampen cooperation compared with homogeneous groups, as do 'balanced' distributions of both heterogeneities (where individuals facing high risk levels receive high endowments and vice versa). However, groups with 'unbalanced' heterogeneities (where those facing high risk levels receive low endowments and vice versa) demonstrate cooperation at similar levels to that of homogeneous groups.At the individual level, risk drives cooperative behaviour, although its impact is influenced by relative wealth levels when both forms of heterogeneity are present.These findings suggest the need for a more in‐depth look at the role and interaction of risk and wealth heterogeneities in conservation management. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Since the ingenious discovery of zero-determinant (ZD) strategies by Press and Dyson, many efforts have been devoted to the evolutionary performance of ZD strategies. Recently, the effects of higher-order interactions on evolutionary games have attracted widespread interests, whereas it remains unknown how higher-order interactions affect the evolutionary performance of ZD strategies. This paper focuses on the role of higher-order interactions on evolutionary ZD strategies in iterated public goods game, where the baseline payoff is a key parameter to describe nodes’ extent of reciprocity in both first-order and second-order interactions. Through the adaptive-like dynamics, we found that there is a critical value of each network, above which the networked game will converge to a consensus state where all the nodes obtain the same payoff. This critical value is significantly affected by the relative strength of higher-order interactions with a U-shaped trend. Numerical simulations are carried out to explore how the network structures affect the dynamics. The results in networks with different sizes indicate that networks with higher average degree are more easily to converge to the consensus state. The simulations on a real-world network further support the theoretical conclusions.

A good group reputation often facilitates more efficient synergistic teamwork in production activities. Here we translate this simple motivation into a reputation-based synergy and discounting mechanism in the public goods game. Specifically, the reputation type of a group, either good or bad determined by a reputation threshold, modifies the nonlinear payoff structure described by a unified reputation impact factor. Results show that this reputation-based incentive mechanism could effectively promote cooperation compared with linear payoffs, despite the coexistence of synergy and discounting effects. Notably, the complicated interactions between reputation impact and reputation threshold result in a sharp phase transition from full cooperation to full defection. We also find that the presence of a few discounting groups could increase the average payoffs of cooperators, leading to an interesting phenomenon that when the reputation threshold is raised, the gap between the average payoffs of cooperators and defectors increases while the overall payoff decreases. We further extend our framework to heterogeneous situations and show how the variability of individuals affect the evolutionary outcomes. Our work provides important insights into facilitating cooperation in social groups.

Mobilizing domestic resources is vital in financing domestic investment and social programmes, which are essential for reducing poverty in developing countries. We consider citizens' willingness to contribute to public goods as one mechanism for domestic resource mobilization. In particular, we are interested in how willingness to contribute varies on three dimensions: inequality in initial endowments, public good outreach (local vs. national), and the expected impact of giving. We conducted a preregistered (AEARCTR-0007746) online experiment with a sample of 900 respondents in South Africa. First, public goods game tasks with equal and unequal endowments were compared to estimate inequality impacts. Second, a dictator game decision with donations to a national charity was compared to the local public goods game to study the effect of project outreach. Finally, to estimate donation impact, charity decisions with quadrupled contributions were compared to those with doubled contributions. We find overall high levels of contribution, with much overlap across the different contexts considered. We note that the highest endowment proportion is contributed in the unequal context, with low endowment players giving the highest share of their endowments. Response time data shows that decisions take longer where donation impact is higher, and where endowments are unequal, particularly for those receiving lower endowments. [ABSTRACT FROM AUTHOR]

Do economic games show evidence of altruistic or self-interested motivations in humans? A huge body of empirical work has found contrasting results. While many participants routinely make costly decisions that benefit strangers, consistent with the hypothesis that humans exhibit a biologically novel form of altruism (or "prosociality"), many participants also typically learn to pay fewer costs with experience, consistent with self-interested individuals adapting to an unfamiliar environment. Key to resolving this debate is explaining the famous "restart effect," a puzzling enigma whereby failing cooperation in public goods games can be briefly rescued by a surprise restart. Here we replicate this canonical result, often taken as evidence of uniquely human altruism, and show that it 1) disappears when cooperation is invisible, meaning individuals can no longer affect the behavior of their groupmates, consistent with strategically motivated, self-interested, cooperation; and 2) still occurs even when individuals are knowingly grouped with computer players programmed to replicate human decisions, consistent with confusion. These results show that the restart effect can be explained by a mixture of self-interest and irrational beliefs about the game's payoffs, and not altruism. Consequently, our results suggest that public goods games have often been measuring self-interested but confused behaviors and reject the idea that conventional theories of evolution cannot explain the results of economic games. [ABSTRACT FROM AUTHOR]

The established imitation protocol mandates that participants observe and learn strategies from the most successful individuals in their vicinity. Previous studies have highlighted the critical role of this protocol in understanding the mechanisms that drive the evolution of cooperation. Nevertheless, individuals often exhibit a natural reluctance to adopt substantial changes rapidly. In this context, we integrate the concept of investment trustworthiness into the strategy updating process and explore the outcomes of dynamic beliefs through numerical simulations. Our results demonstrate that dynamic trustworthiness significantly supports cooperation. Cooperators impede the incursion of defectors by progressively reducing their willingness to invest, thus fostering the formation of cooperative clusters. Our findings suggest that while sensitivity to higher payoffs bolsters cooperation, a tempered response to negative payoffs is advantageous. Additionally, the initial distribution of willingness is pivotal for the success of this dynamic. Our study expands the repertoire of strategy update techniques in investigating the evolution of cooperation and offers profound insights into the complexities of human cooperative behaviour. • Dynamic trustworthiness aids in strategy updates. • Sensitivity to payoffs enhances cooperation. • Moderate response to losses promotes success. • Initial willingness distribution is key for dynamics. • Formation of large clusters critical for cooperative success. [ABSTRACT FROM AUTHOR]

As a social welfare, pension insurance has provided a great assistance to retiree in maintaining their livelihoods. In order to reward the contributions made by cooperators, an additional pension income is provided to them. In this paper, we study a public goods game based on the pension system on population structure, in which only cooperators can purchase pension insurance and receive pension benefits upon meeting specified conditions. In the simulation, we demonstrate the evolution of cooperation frequency over time and investigate the influence of insurance premium, pension baseline, the number of defected neighbors of cooperators, and the enhancement factor on the cooperation frequency. Additionally, we examine the impact of the pension system on cooperative behavior in triangular and hexagonal networks. Our results suggest that in the public goods game on networked structure, the pension system not only fails to promote cooperation but actually inhibits it, even when cooperators do not have to pay any costs and can receive pensions when conditions are met. [ABSTRACT FROM AUTHOR]

For cooperation to be beneficial, cooperators should be able to differentiate individuals who are willing to cooperate from free-riders. In the absence of kin or of familiar individuals, phenotypic similarity (e.g. in terms of language) can be used as a cue of how likely two or more individuals are to behave similarly (whether they will cooperate or free-ride). Thus, phenotypic similarity could affect cooperation. However, it is unclear whether humans respond to any type of phenotypic similarity or whether only salient phenotypic traits guide cooperation. We tested whether within-group, non-salient phenotypic similarity affects cooperation in 280, 3 to 10 year old children and in 76 young adults (mean 19.8 years old) in the UK. We experimentally manipulated the degree of phenotypic similarity in three computer-based experiments. We found no evidence of a preference for, or greater cooperation with, phenotypically similar individuals in children, even though children displayed ingroup preference. Conversely, young adults cooperated more with phenotypically similar than with phenotypically diverse individuals to themselves. Our results suggest that response to non-salient phenotypic similarity varies with age and that young adults may pay more attention to non-salient cues of diversity then children.

Inequality affects how people make social decisions. Laboratory research has shown that when income inequality is simulated using cooperative economic games, groups with higher inequality often generate less wealth overall, with poorer group members receiving the worst outcomes. This study links these experimental findings to real world inequality and applies a decision model to explain the effects in terms of social decision-making dynamics. Using a pre-existing dataset from 255 groups playing a public goods game in thirteen economically diverse societies, we show that in nations with higher inequality, groups contribute less (Research question (RQ) 1). Further, we find that higher inequality is associated with lower optimism regarding others’ contributions at the outset of the game and increased sensitivity to others’ contributions, which accelerates the decay of cooperation (RQ2). These effects might be explained by national differences in social capital as expressed by trust and adherence to civic norms (RQ3). Using the European Values Survey, we replicate the negative association between inequality and contributions to a public good by examining national volunteering rates (RQ4).

Who is cooperative? Although Big Five (B5) Agreeableness and HEXACO Honesty-Humility are correlates of charitable prosociality, distinctions between "charity" and "cooperation" suggest that additional traits could be associated with cooperative prosociality. Echoing prior theoretical and empirical indications that B5 Openness/Intellect may play a role in cooperation, Study 1 (N = 119; exploratory) revealed a significant correlation between Openness/Intellect and cooperativeness in the one-shot Public Goods Game that did not generalize to charitableness in the Dictator Game. We therefore conducted three preregistered replications to discern the robustness of this Openness/Intellect–cooperativeness link. As expected, Openness/Intellect showed no consistent correlation with charitable behavior. Surprisingly, the predicted correlation between Openness/Intellect and cooperative behavior was also inconsistent, partially replicating in Study 3 (N = 304) but not Studies 2 or 4 (Ns = 131; 552). Across our replications, cooperative behavior was most strongly correlated with Honesty-Humility (internal meta-analytic ρ =.15, p =.005). The correlation between Openness/Intellect and cooperative behavior across our replications was significant and identical in magnitude to that between Agreeableness and cooperative behavior, though this effect-size was weak (internal meta-analytic ρ =.08, p <.001). We therefore conclude that Openness/Intellect is a nonnull but very modest correlate of cooperativeness. [ABSTRACT FROM AUTHOR]