Reputation, a universal currency for human social interactions

The importance of need-altruism and kin-altruism to blood donor behaviour for black and white people

BACKGROUND

Need-altruism (a preference to help people in need) and kin-altruism (a preference to help kin over non-kin) underlie two hypotheses for voluntary blood donation: (i) Need-altruism underlies motivations for volunteer blood donation and (ii) Black people express a stronger preference for kin-altruism, which is a potential barrier to donation. This paper tests these hypotheses and explores how need- and kin-altruism are associated with wider altruistic motivations, barriers, and strategies to encourage donation.

METHODS

We assessed need- and kin-altruism, other mechanisms-of-altruism (e.g., reluctant-altruism), barriers, strategies to encourage donation, donor status, and willingness-to-donate across four groups based on ethnicity (Black; White), nationality (British; Nigerian), and country-of-residence: (i) Black-British people (n = 395), and Black-Nigerian people (ii) in the UK (n = 97) or (iii) across the rest of the world (n = 101), and (v) White-British people in the UK (n = 452). We also sampled a Black-Nigerian Expert group (n = 60).

RESULTS

Need-altruism was higher in donors and associated with willingness-to-donate in non-donors. Levels of kin-altruism did not differ between Black and White people, but need-altruism was lower in Black-British people. Kin-altruism was associated with a preference for incentives, and need-altruism with a preference for recognition (e.g., a thank you) as well as an increased willingness-to-donate for Black non-donors. Need-altruism underlies a blood-donor-cooperative-phenotype.

CONCLUSION

Need-altruism is central to blood donation, in particular recruitment. Lower need-altruism may be a specific barrier for Black-British people. Kin-altruism is important for Black non-donors. The blood donor cooperative phenotype deserves further consideration. Implications for blood services are discussed.

Children are eager to take credit for prosocial acts, and cost affects this tendency

We report two experiments on children's tendency to enhance their reputations through communicative acts. In the experiments, 4-year-olds (N = 120) had the opportunity to inform a social partner that they had helped him in his absence. In a first experiment, we pitted a prosocial act ("Let's help clean up for Doggie!") against an instrumental act ("Let's move these out of our way"). Children in the prosocial condition were quicker to inform their partner of the act and more likely to protest when another individual was given credit for it. In a second experiment, we replicated the prosocial condition but with a new manipulation: high-cost versus low-cost helping. We manipulated both the language surrounding cost (i.e., "This will be pretty tough to clean up" vs. "It will be really easy to clean this up") and how difficult the task itself was. As predicted, children in the high-cost condition were quicker to inform their partner of the act and more likely to take back credit for it. These results suggest that even 4-year-old children make active attempts to elicit positive reputational judgments for their prosocial acts, with cost as a moderating factor.

Reputations for treatment of outgroup members can prevent the emergence of political segregation in cooperative networks

Reputation systems promote cooperation and tie formation in social networks. But how reputations affect cooperation and the evolution of networks is less clear when societies are characterized by fundamental, identity-based, social divisions like those centered on politics in the contemporary U.S. Using a large web-based experiment with participants (N = 1073) embedded in networks where each tie represents the opportunity to play a dyadic iterated prisoners' dilemma, we investigate how cooperation and network segregation varies with whether and how reputation systems track behavior toward members of the opposing political party (outgroup members). As predicted, when participants know others' political affiliation, early cooperation patterns show ingroup favoritism. As a result, networks become segregated based on politics. However, such ingroup favoritism and network-level political segregation is reduced in conditions in which participants know how others behave towards participants from both their own party and participants from the other party. These findings have implications for our understanding of reputation systems in polarized contexts.

Warming up cool cooperators

Explaining why someone repeats high-cost cooperation towards non-reciprocating strangers is difficult. Warm glow offers an explanation. We argue that warm glow, as a mechanism to sustain long-term cooperation, cools off over time but can be warmed up with a simple intervention message. We tested our predictions in the context of repeat voluntary blood donation (high-cost helping of a non-reciprocating stranger) across 6 studies: a field-based experiment (n = 5,821) comparing warm-glow and impure-altruism messages; an implementation study comparing a 3-yr pre-implementation period among all first-time donors in Australia (N = 270,353) with a 2-yr post-implementation period (N = 170, 317); and 4 studies (n = 716, 1,124, 932, 1,592) exploring mechanisms. We show that there are relatively warm and cool cooperators, not cooling cooperators. Cooperation among cool cooperators is enhanced by a warm-glow-plus-identity message. Furthermore, the behavioural facilitation of future cooperation, by booking an appointment, is associated with being a warm cooperator. Societal implications are discussed.

Co-evolution of conditional cooperation and social norm

The co-evolution of conditional cooperation and social norms has garnered significant attention, yet the underlying mechanisms remain elusive. Social norms result from empirical expectations, individual expectations of group behavior, and normative expectations, the population's expectations of individual behavior. Aligning these expectations aids in norm formation, but diverse individual reactions to observed behavior and their sensitivity to norm conformity can be challenging. In our study, the agents are initially endowed with diverse conditional expectations, which mirror their anticipations regarding group behavior and their inherent inclination to conform to social norms, indicative of their sensitivity to psychic costs. These agents engage in a repeated public goods game, where their decisions to cooperate are shaped by their conditional expectations and the observed levels of cooperation within their group. Concurrently, free riders experience psychic costs determined by the overall level of cooperation, contribution costs, and the individual's inclination to adhere to social norms. Remarkably, our simulations unveil that agents commencing with random conditional expectations and a propensity to conform to norms can adapt to lower conditional expectations and moderate their propensity to conform to norms when initial cooperation levels are high and the contribution cost is reduced. Interestingly, increasing contribution costs intensify the population's response to norm enforcement, but this doesn't always result in a corresponding increase in cooperation. By incorporating population diversity and accounting for empirical and normative expectations within our model, we gain valuable insights into the intricate relationship between conditional cooperation and the emergence of social norms.

An Asymmetric Effect: Physical and Simulated Confederate's Mere Presence Induce a Preference for Deontological Over Utilitarian Judgment

People may behave differently in a shared physical context due to the mere presence of others. The study examined whether individual moral judgments were subject to the confederate's presence. Experiment 1 supported the hypothesis that the confederate's presence, relative to the control group, increased deontological judgment, disapproving of sacrificing a person's lifetime or interest for preserving the greater good of others. Experiment 2 investigated whether the results extend to mental space. The result revealed that simulating a positive interaction with the confederate significantly increased the preference for deontological judgments relative to the control group. However, the effect disappeared if the participants were required to simulate only the person from the scenario that did not include any additional background contexts. These results demonstrated that the confederate's physical presence and simulated confederate's presence always preferred deontological judgments over utilitarian judgments. The findings suggested that the asymmetric moral effect occurred in the physical realm and mental space.

Reputation and reciprocity

Reputation and reciprocity are key mechanisms for cooperation in human societies, often going hand in hand to favor prosocial behavior over selfish actions. Here we review recent researches at the interface of physics and evolutionary game theory that explored these two mechanisms. We focus on image scoring as the bearer of reputation, as well as on various types of reciprocity, including direct, indirect, and network reciprocity. We review different definitions of reputation and reciprocity dynamics, and we show how these affect the evolution of cooperation in social dilemmas. We consider first-order, second-order, as well as higher-order models in well-mixed and structured populations, and we review experimental works that support and inform the results of mathematical modeling and simulations. We also provide a synthesis of the reviewed researches along with an outlook in terms of six directions that seem particularly promising to explore in the future.

Effects of co-players' identity and reputation in the public goods game

Players' identity and their reputation are known to influence cooperation in economic games, but little is known about how they interact. Our study aimed to understand how presenting pre-programmed co-players' identities (face photos; names) along with their previous cooperation history (reputation) could influence participants' cooperative decisions in a public goods game. Participants (N = 759) were allocated to one of six experimental groups: (i) control (no information); (ii) only reputation (neutral, free-rider, or cooperative); (iii) only face; (iv) face with reputation; (v) only name; (vi) name with reputation. In the reputation group, cooperation significantly decreased when free-riders were playing and significantly increased when they were cooperators. Person's identity affected cooperativeness only when combined with reputation: face photo mitigated the negative effect of the free-rider reputation, while name identity mitigated any significant effect expected for reputation. Our study suggests a hierarchy: reputation changes cooperation, but a person's identity can modulate reputation.

Score-mediated mutual consent and indirect reciprocity

Helping strangers at a cost to oneself is a hallmark of many human interactions, but difficult to justify from the viewpoint of natural selection, particularly in anonymous one-shot interactions. Reputational scoring can provide the necessary motivation via "indirect reciprocity," but maintaining reliable scores requires close oversight to prevent cheating. We show that in the absence of such supervision, it is possible that scores might be managed by mutual consent between the agents themselves instead of by third parties. The space of possible strategies for such "consented" score changes is very large but, using a simple cooperation game, we search it, asking what kinds of agreement can i) invade a population from rare and ii) resist invasion once common. We prove mathematically and demonstrate computationally that score mediation by mutual consent does enable cooperation without oversight. Moreover, the most invasive and stable strategies belong to one family and ground the concept of value by incrementing one score at the cost of the other, thus closely resembling the token exchange that underlies money in everyday human transactions. The most successful strategy has the flavor of money except that agents without money can generate new score if they meet. This strategy is evolutionarily stable, and has higher fitness, but is not physically realizable in a decentralized way; when conservation of score is enforced more money-like strategies dominate. The equilibrium distribution of scores under any of this family of strategies is geometric, meaning that agents with score 0 are inherent to money-like strategies.

Clustering drives cooperation on reputation networks, all else fixed

Reputation-based cooperation on social networks offers a causal mechanism between graph properties and social trust. Using a simple model, this paper demonstrates the underlying mechanism in a way that is accessible to scientists not specializing in networks or mathematics. The paper shows that when the size and degree of the network is fixed (i.e. all graphs have the same number of agents, who all have the same number of connections), it is the clustering coefficient that drives differences in how cooperative social networks are.

Communicating the cost of your altruism makes you cool—competitive altruism and sexual selection in a real-life charity situation

Abstract

Maintaining a good reputation is crucial for humans. Altruism, e.g. charity, may serve as a costly signal that enhances reputation based on the real or communicated cost. Fundraising via charity running triggers competitive altruism when potential donors donate in reaction to the reputation increase of the fundraiser. Using real-life data of marathonists and half-marathonists (388 runners) and their 9281 donors, the present research focuses on how the communicated cost and goal of a charity run affected the potential donors. We analysed the introductory texts of the runners presented online according to the cost and the social benefit of the fundraising communicated by them. We have shown that emphasizing more the subjective cost of running and the social benefit of the goal, or writing a longer text, attracted more donors and, even though the average amount of donation per donor did not increase, still lead to a greater amount of donations collected overall by the fundraiser. It was also shown that a higher communicated subjective cost resulted in a higher ratio of opposite-sex donors, both in the case of male and female runners, suggesting that the communication of the cost of an altruistic act might be the object of sexual selection.

Significance statement

A good reputation is crucial for humans, as a reputable person enjoys several benefits. One way to maintain a good reputation is to be altruistic, e.g. doing charity. A seemingly high cost and a socially accepted goal may result in a higher reputation. Using data from a charity running community we demonstrate that fundraisers who emphasize their subjective cost (how difficult to run), and emphasize the good goal of the charity, attract more donors, and even though the average amount of each donation does not increase, a higher number of donors results in a greater amount of donations collected overall. Talking about the difficulties of the charity run results in a higher ratio of opposite-sex donors. Our results may be helpful to plan more successful charity events or to make a human community more altruistic and cooperative in general.

Workplace gossip and the evolution of friendship relations: the role of complex contagion

Gossip is a pervasive phenomenon in organizations causing many individuals to have second-hand information about their colleagues. However, whether it is used to inform friendship choices (i.e., friendship creation, friendship maintenance, friendship discontinuation) is not that evident. This paper articulates and empirically tests a complex contagion model to explain how gossip, through its reputational effects, can affect the evolution of friendship ties. We argue that hearing gossip from more than a single sender (and about several targets) impacts receivers’ friendships with the gossip targets. Hypotheses are tested in a two-wave sociometric panel study among 148 employees in a Dutch childcare organization. Stochastic actor-oriented models reveal positive gossip favors receiver-target friendships, whereas negative gossip inhibits them. We also find evidence supporting that, for damaging relationships, negative gossip needs to originate in more than a single sender. Positive gossip about a high number of targets discourages friendships with colleagues in general, while negative gossip about many targets produces diverging trends. Overall, the study demonstrates that second-hand information influences the evolution of expressive relations. It also underscores the need to refine and extend current theorizing concerning the multiple (and potentially competing) psychological mechanisms causing some of the observed effects.

Why do people gossip? Reputation promotes honest reputational information sharing

Gossip, sharing information about an absent person, is an important way of spreading reputational information, crucial in fostering human cooperation. However, why should information possessors engage in gossip, and why should they be honest? We addressed this question based on a reputational account. In study 1, we found that when observed by potential investors, people were willing to pay more to share reputational information with those in need. Moreover, engaging in gossip did confer reputational benefits for gossipers by receiving more trust from investors, and gossipers' willingness to gossip predicted their subsequent trustworthiness. Study 2 further verified that observability promoted only honest information sharing and deterred dishonest gossiping. Consistently, only honest gossipers were trusted more, while dishonest gossipers were perceived to be even less trustworthy than non-gossipers, and only the motivation for honest gossiping could reflect gossipers' trustworthiness. These findings suggest that reputation can provide a solution to encourage gossiping and secure honesty.

Factors related to the social network of core members of elderly care service social organizations: a cross-sectional study

Background

The social network of the core members of elderly care service social organizations could affect the performance of the organization, while studies concerning its related factors are limited. We aimed to explore factors that are associated with the social network of core members from elderly care service social organizations and provide references and suggestions for improving elderly care services.

Methods

This cross-sectional study employed a multi-stage stratified sampling method, and collected data concerning social network, demographic information and occupation. Univariate analysis and binary logistic regression were used to analyze factors that could affect the social network of the core members.

Results

Our results demonstrated that there is low social network of core members of elderly care social organizations. Out of the total membership, men (AOR = 1.708; 95%CI: 1.034–2.823), those with senior high school education (AOR = 1.923; 95%CI: 1.053–3.511), those with a college degree and above (AOR = 3.010; 95%CI: 1.591–5.692) and those that receive awards related to elderly care services (AOR = 2.260; 95%CI: 1.285–3.976) were associated with higher social network scores.

Conclusions

Our data successfully characterized the social status of core members of elderly care organizations. Therefore, health care professionals and policy makers in social organizations should use this knowledge in the care and service provision to the elderly; and implement actions that would promote networking in social organizations.

Holds enable one-shot reciprocal exchange

Strangers routinely cooperate and exchange goods without any knowledge of one another in one-off encounters without recourse to a third party, an interaction that is fundamental to most human societies. However, this act of reciprocal exchange entails the risk of the other agent defecting with both goods. We examine the choreography for safe exchange between strangers, and identify the minimum requirement, which is a shared hold, either of an object, or the other party; we show that competing agents will settle on exchange as a local optimum in the space of payoffs. Truly safe exchanges are rarely seen in practice, even though unsafe exchange could mean that risk-averse agents might avoid such interactions. We show that an 'implicit' hold, whereby an actor believes that they could establish a hold if the other agent looked to be defecting, is sufficient to enable the simple swaps that are the hallmark of human interactions and presumably provide an acceptable trade-off between risk and convenience. We explicitly consider the particular case of purchasing, where money is one of the goods.

How ‘who someone is’ and ‘what they did’ influences gossiping about them

To understand, predict, and help correct each other’s actions we need to maintain accurate, up-to-date knowledge of people, and communication is a critical means by which we gather and disseminate this information. Yet the conditions under which we communication social information remain unclear. Testing hypotheses generated from our theoretical framework, we examined when and why social information is disseminated about an absent third party: i.e., gossiped. Gossip scenarios presented to participants (e.g., “Person-X cheated on their exam”) were based on three key factors: (1) target (ingroup, outgroup, or celebrity), (2) valence (positive or negative), and (3) content. We then asked them (a) whether they would spread the information, and (b) to rate it according to subjective valence, ordinariness, interest level, and emotion. For ratings, the scenarios participants chose to gossip were considered to have higher valence (whether positive or negative), to be rarer, more interesting, and more emotionally evocative; thus showing that the paradigm was meaningful to subjects. Indeed, for target, valence, and content, a repeated-measures ANOVA found significant effects for each factor independently, as well as their interactions. The results supported our hypotheses: e.g., for target, more gossiping about celebrities and ingroup members (over strangers); for valence, more about negative events overall, and yet for ingroup members, more positive gossiping; for content, more about moral topics, with yet all domains of social content communicated depending on the situation—context matters, influencing needs. The findings suggest that social knowledge sharing (i.e., gossip) involves sophisticated calculations that require our highest sociocognitive abilities, and provide specific hypotheses for future examination of neural mechanisms.

Gossip promotes cooperation only when it is pro-socially motivated

Humans are often shown to cooperate with one another. Most of the mechanisms that foster cooperation among humans rely on reputation, which itself relies on the acquisition of information about other people’s behaviors. Gossip has been proposed as a cheap yet efficient tool to acquire information, and it has largely been proved to be an effective means to foster and maintain cooperation. However, empirical studies supporting this claim have ignored two aspects: (1) they often compared gossip to treatments in which no reputation was available, impeding a direct assessment of whether it is gossip that promotes cooperation or rather the introduction of a reputation system; and (2) they focused on pro-social gossip (e.g., gossip aimed at helping the receiver), neglecting the impact of other types of gossip. We show here that, in contrast with the widespread notion that gossip promotes cooperation, gossip mostly depletes cooperation compared to first-hand information. If lying is fruitful for individuals or if a group’s behavior is largely uncooperative, gossip leads to negative reputational information and decreased cooperation.

Four Puzzles of Reputation-Based Cooperation : Content, Process, Honesty, and Structure

Research in various disciplines has highlighted that humans are uniquely able to solve the problem of cooperation through the informal mechanisms of reputation and gossip. Reputation coordinates the evaluative judgments of individuals about one another. Direct observation of actions and communication are the essential routes that are used to establish and update reputations. In large groups, where opportunities for direct observation are limited, gossip becomes an important channel to share individual perceptions and evaluations of others that can be used to condition cooperative action. Although reputation and gossip might consequently support large-scale human cooperation, four puzzles need to be resolved to understand the operation of reputation-based mechanisms. First, we need empirical evidence of the processes and content that form reputations and how this may vary cross-culturally. Second, we lack an understanding of how reputation is determined from the muddle of imperfect, biased inputs people receive. Third, coordination between individuals is only possible if reputation sharing and signaling is to a large extent reliable and valid. Communication, however, is not necessarily honest and reliable, so theoretical and empirical work is needed to understand how gossip and reputation can effectively promote cooperation despite the circulation of dishonest gossip. Fourth, reputation is not constructed in a social vacuum; hence we need a better understanding of the way in which the structure of interactions affects the efficiency of gossip for establishing reputations and fostering cooperation.

Gossip and reputation in everyday life

Gossip-a sender communicating to a receiver about an absent third party-is hypothesized to impact reputation formation, partner selection, and cooperation. Laboratory experiments have found that people gossip about others' cooperativeness and that they use gossip to condition their cooperation. Here, we move beyond the laboratory and test several predictions from theories of indirect reciprocity and reputation-based partner selection about the content of everyday gossip and how people use it to update the reputation of others in their social network. In a Dutch community sample (N = 309), we sampled daily events in which people either sent or received gossip about a target over 10 days (ngossip = 5284). Gossip senders frequently shared information about targets' cooperativeness and did so in ways that minimize potential retaliation from targets. Receivers overwhelmingly believed gossip to be true and updated their evaluation of targets based on gossip. In turn, a positive shift in the evaluation of a target was associated with higher intentions to help them in future interactions, and with lower intentions to avoid them in the future. Thus, gossip is used in daily life to impact and update reputations in a way that enables partner selection and indirect reciprocity. This article is part of the theme issue 'The language of cooperation: reputation and honest signalling'.

Honesty and dishonesty in gossip strategies: a fitness interdependence analysis

Gossip, or sharing information about absent others, has been identified as an effective solution to free rider problems in situations with conflicting interests. Yet, the information transmitted via gossip can be biased, because gossipers may send dishonest information about others for personal gains. Such dishonest gossip makes reputation-based cooperation more difficult to evolve. But when are people likely to share honest or dishonest gossip? We build formal models to provide the theoretical foundation for individuals' gossip strategies, taking into account the gossiper's fitness interdependence with the receiver and the target. Our models across four different games suggest a very simple rule: when there is a perfect match (mismatch) between fitness interdependence and the effect of honest gossip, the gossiper should always be honest (dishonest); however, in the case of a partial match, the gossiper should make a choice based on their fitness interdependence with the receiver and the target and the marginal cost/benefit in terms of pay-off differences caused by possible choices of the receiver and the target in the game. Moreover, gossipers can use this simple rule to make optimal decisions even under noise. We discuss empirical examples that support the predictions of our model and potential extensions.

This article is part of the theme issue ‘The language of cooperation: reputation and honest signalling’.

The benefits of being seen to help others: indirect reciprocity and reputation-based partner choice

When one individual helps another, it benefits the recipient and may also gain a reputation for being cooperative. This may induce others to favour the helper in subsequent interactions, so investing in being seen to help others may be adaptive. The best-known mechanism for this is indirect reciprocity (IR), in which the profit comes from an observer who pays a cost to benefit the original helper. IR has attracted considerable theoretical and empirical interest, but it is not the only way in which cooperative reputations can bring benefits. Signalling theory proposes that paying a cost to benefit others is a strategic investment which benefits the signaller through changing receiver behaviour, in particular by being more likely to choose the signaller as a partner. This reputation-based partner choice can result in competitive helping whereby those who help are favoured as partners. These theories have been confused in the literature. We therefore set out the assumptions, the mechanisms and the predictions of each theory for how developing a cooperative reputation can be adaptive. The benefits of being seen to be cooperative may have been a major driver of sociality, especially in humans. This article is part of the theme issue 'The language of cooperation: reputation and honest signalling'.

Networks of reliable reputations and cooperation: a review

Reputation has been shown to provide an informal solution to the problem of cooperation in human societies. After reviewing models that connect reputations and cooperation, we address how reputation results from information exchange embedded in a social network that changes endogenously itself. Theoretical studies highlight that network topologies have different effects on the extent of cooperation, since they can foster or hinder the flow of reputational information. Subsequently, we review models and empirical studies that intend to grasp the coevolution of reputations, cooperation and social networks. We identify open questions in the literature concerning how networks affect the accuracy of reputations, the honesty of shared information and the spread of reputational information. Certain network topologies may facilitate biased beliefs and intergroup competition or in-group identity formation that could lead to high cooperation within but conflicts between different subgroups of a network. Our review covers theoretical, experimental and field studies across various disciplines that target these questions and could explain how the dynamics of interactions and reputations help or prevent the establishment and sustainability of cooperation in small- and large-scale societies.

This article is part of the theme issue ‘The language of cooperation: reputation and honest signalling’.

The content and structure of reputation domains across human societies: a view from the evolutionary social sciences

Reputations are an essential feature of human sociality and the evolution of cooperation and group living. Much scholarship has focused on reputations, yet typically on a narrow range of domains (e.g. prosociality and aggressiveness), usually in isolation. Humans can develop reputations, however, from any collective information. We conducted exploratory analyses on the content, distribution and structure of reputation domain diversity across cultures, using the Human Relations Area Files ethnographic database. After coding ethnographic texts on reputations from 153 cultures, we used hierarchical modelling, cluster analysis and text analysis to provide an empirical view of reputation domains across societies. Findings suggest: (i) reputational domains vary cross-culturally, yet reputations for cultural conformity, prosociality, social status and neural capital are widespread; (ii) reputation domains are more variable for males than females; and (iii) particular reputation domains are interrelated, demonstrating a structure consistent with dimensions of human uniqueness. We label these features: cultural group unity, dominance, neural capital, sexuality, social and material success and supernatural healing. We highlight the need for future research on the evolution of cooperation and human sociality to consider a wider range of reputation domains, as well as their social, ecological and gender-specific variability. This article is part of the theme issue 'The language of cooperation: reputation and honest signalling'.

Reputation and socio-ecology in humans

Reputation is a fundamental feature of human sociality as it sustains cooperative relationships among unrelated individuals. Research from various disciplines provides insights on how individuals form impressions of others, condition their behaviours based on the reputation of their interacting partners and spread or learn such reputations. However, past research has often neglected the socio-ecological conditions that can shape reputation systems and their effect on cooperation. Here, we outline how social environments, cultural values and institutions come to play a crucial role in how people navigate reputation systems. Moreover, we illustrate how these socio-ecological dimensions affect the interdependence underlying social interactions (e.g. potential recipients of reputational benefits, degree of dependence) and the extent to which reputation systems promote cooperation. To do so, we review the interdisciplinary literature that illustrates how reputation systems are shaped by the variation of prominent ecological features. Finally, we discuss the implications of a socio-ecological approach to the study of reputation and outline potential avenues for future research. This article is part of the theme issue 'The language of cooperation: reputation and honest signalling'.

The language of cooperation: reputation and honest signalling

Large-scale non-kin cooperation is a unique ingredient of human success. This type of cooperation is challenging to explain in a world of self-interested individuals. There is overwhelming empirical evidence from different disciplines that reputation and gossip promote cooperation in humans in different contexts. Despite decades of research, important details of reputation systems are still unclear. Our goal with this theme issue is to promote an interdisciplinary approach that allows us to explore and understand the evolution and maintenance of reputation systems with a special emphasis on gossip and honest signalling. The theme issue is organized around four main questions: What are the necessary conditions for reputation-based systems? What is the content and context of reputation systems? How can reputations promote cooperation? And, what is the role of gossip in maintaining reputation systems and thus cooperation? This article is part of the theme issue 'The language of cooperation: reputation and honest signalling'.

Evaluating mechanisms that could support credible reputations and cooperation: cross-checking and social bonding

Gossip is believed to be an informal device that alleviates the problem of cooperation in humans. Communication about previous acts and passing on reputational information could be valuable for conditional action in cooperation problems and pose a punishment threat to defectors. It is an open question, however, what kind of mechanisms can make gossip honest and credible and reputational information reliable, especially if intense competition for reputations does not exclusively dictate passing on honest information. We propose two mechanisms that could support the honesty and credibility of gossip under such a conflict of interest. One is the possibility of voluntary checks of received evaluative information from different sources and the other is social bonding between the sender and the receiver. We tested the efficiency of cross-checking and social bonding in a laboratory experiment where subjects played the Prisoner's Dilemma with gossip interactions. Although individuals had confidence in gossip in both conditions, we found that, overall, neither the opportunities for cross-checking nor bonding were able to maintain cooperation. Meanwhile, strong competition for reputation increased cooperation when individuals' payoffs depended greatly on their position relative to their rivals. Our results suggest that intense competition for reputation facilitates gossip functioning as an informal device promoting cooperation.

This article is part of the theme issue ‘The language of cooperation: reputation and honest signalling’.

Altruism as an Explanation for Human Consanguinity

BACKGROUND

Human inbreeding is a sociobiological puzzle. Despite widespread knowledge of its potential for genetic disorders, human consanguinity remains surprisingly common. The current reasons explaining its continued persistence in today's modern world have major shortcomings.

SUMMARY

We propose that the Neolithic Agrarian revolution modified the structure of populations. It increased competition for the limited resources in which a larger group had better chances of survival. As a result, small, drifting, socially open bands of hunter-gatherers were transformed into bigger, less mobile, and more powerful kinship groups (tribes). In this transformation, a central role was played by human trust - an aspect of human altruism which is a universal sociobiological principle of behavior. Altruism (and trust) is an essential premise of social contracts such as economic cooperation, marriage arrangement, and creation of alliances between people. In kinship groups, human trust is limited to kin, so tribes remain small, economically poor, and consanguineous due to lack of nonkin mates. The expanding of trust from kin to that of nonbiological relatives increases the size of human groups, fosters economic wealth, and decreases the rate of consanguinity. Key Messages: The lack of nonkin altruism leads to: (a) poverty (due to poor economic cooperation with nonkin), (b) maintaining small group size, and (c) inbreeding.

What blood and organ donation can tell us about cooperation?

High-cost cooperation directed towards strangers is difficult to explain from an evolutionary perspective. Here, it is argued that by studying the behaviours, motivations, and preferences of real-world high-cost cooperators - blood and organ donors - insights can be uncovered into the mechanisms supporting cooperation. In this respect, this article details two novel mechanisms to enhance cooperation in the face of free-riding, (1) 'reactive reluctant altruism' whereby people help because they do not trust others to help and (2) the 'Good Shepherd' effect whereby cooperation is enhanced when people observed others cooperate although the social norm is to free-ride. Finally, it is argued that repeated acts of high-cost cooperation are sustained by a self-selection process based on the reinforcing effect of warm-glow.

Prosocial and punishment behaviors in everyday life

Theory and experiments suggest people have different strategies (1) to condition their prosocial behavior in ways that maximize individual benefits and (2) to punish others who have exploited their own and others' prosocial behaviors. To date, most research testing existing theories has relied on experiments. However, documenting prosocial and punishment behaviors outside of the laboratory via experience sampling and diary methods can yield additional, rich insights. Recent work demonstrates these methods can describe social behaviors in daily life and be used to test theory about how behaviors change across situations and relationships. These methods have exposed discrepancies between what people experience in daily life and the problems researchers want to solve to understand the nature of human prosociality.

Gossip drives vicarious learning and facilitates social connection

Complex language and communication is one of the unique hallmarks that distinguishes humans from most other animals. Interestingly, the overwhelming majority of our communication consists of social topics involving self-disclosure and discussions about others, broadly construed as gossip. Yet the precise social function of gossip remains poorly understood as research has been heavily influenced by folk intuitions narrowly casting gossip as baseless trash talk. Using a novel empirical paradigm that involves real interactions between a large sample of participants, we provide evidence that gossip is a rich, multifaceted construct, that plays a critical role in vicarious learning and social bonding. We demonstrate how the visibility or lack thereof of others' behavior shifts conversational content between self-disclosure and discussions about others. Social information acquired through gossip aids in vicarious learning, directly influencing future behavior and impression formation. At the same time, conversation partners come to influence each other, form more similar impressions, and build robust social bonds. Consistent with prior work, gossip also helps promote cooperation in groups without a need for formal sanctioning mechanisms. Altogether these findings demonstrate the rich and diverse social functions and effects of this ubiquitous human behavior and lay the groundwork for future investigations.

Dealing With Negative Workplace Gossip: From the Perspective of Face

In this study, we investigate the coping response of individuals who are being gossiped about. Drawing on face research and affective events theory, we propose that employees who are targets of negative gossip will actively respond to the gossip about them via engagement in negative gossip themselves. The findings showed that negative workplace gossip stimulated fear of losing face and led to subsequent behavioral responses, namely, engaging in negative gossip. Moreover, self-monitoring, as a moderating mechanism, mitigated the negative impacts of negative workplace gossip on the targets. We discuss theoretical implications for gossip research and note its important practical implications.

Evolution of altruistic punishments among heterogeneous conditional cooperators

It has been known that altruistic punishments solve the free rider problem in public goods games. Considering spatial structure and considering pure strategies significant advances have been made in understanding the evolution of altruistic punishments. However, these models have not considered key behavior regularities observed in experimental and field settings, where the individuals behave like conditional cooperators who are more willing to donate and are also more willing to punish free riders. Considering these behavioral regularities, without imposing a spatial structure on the population, I propose an evolutionary agent-based model in which agents behave like conditional cooperators, each agent’s donation conditional on the difference between the number of donations in the past and the threshold value and the propensity value of the agent. Altruistic punishment depends on the difference between the threshold value of the focal agent and the randomly matched another agent. The simulations show that, for certain inflicted costs of punishments, generous altruistic punishments evolve and stabilize cooperation. The results show that, unlike previous models, it is not necessary to punish all free riders equally; it is necessary to do so in the case of the selfish free riders but not in the case of negative reciprocators.

Emotion expressions shape human social norms and reputations

The emergence of pro-social behaviors remains a key open challenge across disciplines. In this context, there is growing evidence that expressing emotions may foster human cooperation. However, it remains unclear how emotions shape individual choices and interact with other cooperation mechanisms. Here, we provide a comprehensive experimental analysis of the interplay of emotion expressions with two important mechanisms: direct and indirect reciprocity. We show that cooperation in an iterated prisoner's dilemma emerges from the combination of the opponent's initial reputation, past behaviors, and emotion expressions. Moreover, all factors influenced the social norm adopted when assessing the action of others - i.e., how their counterparts' reputations are updated - thus, reflecting longer-term consequences. We expose a new class of emotion-based social norms, where emotions are used to forgive those that defect but also punish those that cooperate. These findings emphasize the importance of emotion expressions in fostering, directly and indirectly, cooperation in society.

Specialized Donor Care Facility Model and Advances in Management of Thoracic Organ Donors

BACKGROUND

Donor hearts and lungs are more susceptible to the inflammatory physiologic changes that occur after brain death. Prior investigations have shown that protocolized management of potential organ donors can rehabilitate donor organs that are initially deemed unacceptable. In this review we discuss advances in donor management models with particular attention to the specialized donor care facility model. In addition we review specific strategies to optimize donor thoracic organs and improve organ yield in thoracic transplantation.

METHODS

We performed a literature review by searching the PubMed database for medical subject heading terms associated with organ donor management models. We also communicated with our local organ procurement organization to gather published and unpublished information first-hand.

RESULTS

The specialized donor care facility model has been shown to improve the efficiency of organ donor management and procurement while reducing costs and minimizing travel and its associated risks. Lung protective ventilation, recruitment of atelectatic lung, and hormone therapy (eg, glucocorticoids and triiodothyronine/thyroxine) are associated with improved lung utilization rates. Stroke volume-based resuscitation is associated with improved heart utilization rates, whereas studies evaluating hormone therapy (eg, glucocorticoids and triiodothyronine/thyroxine) have shown variable results.

CONCLUSIONS

Lack of high-quality prospective evidence results in conflicting practices across organ procurement organizations, and best practices remain controversial. Future studies should focus on prospective, randomized investigations to evaluate donor management strategies. The specialized donor care facility model fosters a collaborative environment that encourages academic inquiry and is an ideal setting for these investigations.

Donor management using a specialized donor care facility is associated with higher organ utilization from drug overdose donors

Drug overdoses have tripled in the United States over the last two decades. With the increasing demand for donor organs, one potential consequence of the opioid epidemic may be an increase in suitable donor organs. Unfortunately, organs from donors dying of drug overdose have poorer utilization rates than other groups of brain-dead donors, largely due to physician and recipient concerns about viral disease transmission. During the study period of 2011 to 2016, drug overdose donors (DODs) account for an increasingly greater proportion of the national donor pool. We show that a novel model of donor care, known as specialized donor care facility (SDCF), is associated with an increase in organ utilization from DODs compared to the conventional model of hospital-based donor care. This is likely related to the close relationship of the SDCF with the transplant centers, leading to improved communication and highly efficient donor care.

Banking on cooperation: an evolutionary analysis of microfinance loan repayment behaviour

Microfinance is an economic development tool that provides loans to low-income borrowers to stimulate economic growth and reduce financial hardship. Lenders typically require joint liability, where multiple borrowers share the responsibility of repaying a group loan. We propose that this lending practice creates a cooperation dilemma similar to that faced by humans and other organisms in nature across many domains. This could offer a real-world test case for evolutionary theories of cooperation from the biological sciences. In turn, such theories could provide new insights into loan repayment behaviour. We first hypothesise how group loan repayment efficacy should be affected by mechanisms of assortment from the evolutionary literature on cooperation, i.e. common ancestry (kin selection), prior interaction (reciprocity), partner choice, similarity of tags, social learning, and ecology and demography. We then assess selected hypotheses by reviewing 41 studies from 32 countries on micro-borrowers' loan repayment, evaluating which characteristics of borrowers are associated with credit repayment behaviour. Surprisingly, we find that kinship is mostly negatively associated with repayment efficacy, but prior interaction and partner choice are both more positively associated. Our work highlights the scope of evolutionary theory to provide systematic insight into how humans respond to novel economic institutions and interventions.

Cooperation through Image Scoring: A Replication

“Image scoring” is a type of social evaluation, originally used in agent-based models, where the reputation of another is numerically assessed. This phenomenon has been studied in both theoretical models and real-life psychology experiments (using human participants). The latter are aimed to create conditions in the laboratory where image scoring can be elicited. One influential paper is that of Wedekind and Milinski (2000), WM. Our paper is a replication of that study, deliberately employing very similar methodology to the original. Accordingly, we had six groups of ten participants play an economic game. In each round, each player was randomly paired with another player whose identity was unknown. The participant was given a binary choice of either (1) donating money to that person, or (2) not donating money. In each round, the player was passively exposed to information about the past generosity of the other player. In our study, we successfully replicated the central result of WM. Participants in our replication gave significantly more money to partners with higher image scores (more generous reputations) than those with lower image scores (less generous reputations). This paper also provides a critical review of the methodology of WM and the study of image scoring.

Testing the two sides of indirect reciprocity in tufted capuchin monkeys

We addressed two different aspects of indirect reciprocity in tufted capuchin monkeys (Sapajus spp.) studying two common cooperative behaviours, grooming and food sharing. In an observational study, we tested whether capuchin monkeys were more likely to groom an individual that had just groomed a group mate than an individual that had not groomed anybody. In an experimental study, we tested whether capuchin monkeys were more likely to share their food with a partner when in the presence of a bystander (or of an image of the eyes of a conspecific) than when alone with their partner. In the observational study, we found an increase in the likelihood of receiving grooming after giving grooming, but this effect seemed to depend on social facilitation rather than on indirect reciprocity, as we found a similar effect after receiving (rather than giving) grooming. In the experimental study, the presence of a bystander or of an image of eyes did not affect the amount of food transferred to a group mate. Overall, these results suggest capuchin monkeys do not engage in indirect reciprocity.

A branded bandage is worth a thousand words: blood branded bandages signal men's generosity and morality

BACKGROUND AND OBJECTIVE

Recruiting and retaining male donors remain an ongoing challenge for blood collection agencies. Research suggests that interventions based on costly signalling theory that allows donors to unobtrusively but publicly signal their donor status may be effective. However, what functions as such a signal and how it is interpreted has not been determined.

MATERIALS AND METHODS

A total of 242 Australian residents (127 female; 115 male) recruited through an online research platform rated their perceptions of a male target wearing (a) no bandage, (b) a regular unmarked bandage or (c) a blood donor branded bandage.

RESULTS

The target wearing a blood donor branded bandage was rated as significantly more generous by female participants and moral compared to both the target who wore no bandage and the target wearing a regular unmarked bandage. The target wearing the unmarked bandage was perceived as significantly less healthy and competent compared to the target not wearing a bandage.

CONCLUSION

A public signal of public donor status conveys the generosity and morality of the wearer. The bandage applied to donors after they have donated can act as such an effective signal, but only when these bandages are clearly branded as resulting from donating blood.

How evolutionary behavioural sciences can help us understand behaviour in a pandemic

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

Behavioral and neural evidence for an evaluative bias against other people's mundane interracial encounters

Evaluating other people’s social encounters from a third-person perspective is an ubiquitous activity of daily life. Yet little is known about how these evaluations are affected by racial bias. To overcome this empirical lacuna, two experiments were conducted. The first experiment used evaluative priming to show that both Black (n = 44) and White Americans (n = 44) assess the same mundane encounters (e.g. two people chatting) less favorably when they involve a Black and a White individual rather than two Black or two White individuals. The second experiment used functional magnetic resonance imaging to demonstrate that both Black (n = 46) and White Americans (n = 42) respond with reduced social reward processing (i.e. lower activity in the ventral striatum) and enhanced mentalizing (e.g. higher activity in the bilateral temporal–parietal junction) toward so-called cross-race relative to same-race encounters. By combining unobtrusive measures from social psychology and social neuroscience, this work demonstrates that racial bias can affect impression formation even at the level of the dyad.

Evolution of conditional cooperation in public good games

Cooperation declines in repeated public good games because individuals behave as conditional cooperators. This is because individuals imitate the social behaviour of successful individuals when their payoff information is available. However, in human societies, individuals cooperate in many situations involving social dilemmas. We hypothesize that humans are sensitive to both success (payoffs) and how that success was obtained, by cheating (not socially sanctioned) or good behaviour (socially sanctioned and adds to prestige or reputation), when information is available about payoffs and prestige. We propose and model a repeated public good game with heterogeneous conditional cooperators where an agent's donation in a public goods game depends on comparing the number of donations in the population in the previous round and with the agent's arbitrary chosen conditional cooperative criterion. Such individuals imitate the social behaviour of role models based on their payoffs and prestige. The dependence is modelled by two population-level parameters: affinity towards payoff and affinity towards prestige. These affinities influence the degree to which agents value the payoff and prestige of role models. Agents update their conditional strategies by considering both parameters. The simulations in this study show that high levels of cooperation are established in a population consisting of heterogeneous conditional cooperators for a certain range of affinity parameters in repeated public good games. The results show that social value (prestige) is important in establishing cooperation.

How dominance hierarchies emerge from conflict: A game theoretic model and experimental evidence

We develop a game theoretic model of conflict and empirically test its predictions to study the emergence of social hierarchies in small groups. Previous research shows uncertainty about actors' ability may lead to more conflict; conflict demonstrates actors' ability and establishes relationships of dominance and submissiveness. Since we assume uncertainty regarding ability to be a crucial cause of conflict, we focus on the effects of different information conditions. We posit that actors know the distribution of abilities in their group and vary whether or not they know (1) their own ability and (2) their interaction partners' interaction histories. Our results from a laboratory experiment closely match qualitative model predictions. Most importantly, conflict produces information about actors' ability, which reduces subsequent conflict. In an exploratory analysis we investigate to what extent gender, social value orientation, risk preferences and a competitive personality account for the quantitative discrepancies between model predictions and subject behavior.

Watching eyes do not stop dogs stealing food: evidence against a general risk-aversion hypothesis for the watching-eye effect

The presence of pictures of eyes reduces antisocial behaviour in humans. It has been suggested that this ‘watching-eye’ effect is the result of a uniquely human sensitivity to reputation-management cues. However, an alternative explanation is that humans are less likely to carry out risky behaviour in general when they feel like they are being watched. This risk-aversion hypothesis predicts that other animals should also show the watching-eye effect because many animals behave more cautiously when being observed. Dogs are an ideal species to test between these hypotheses because they behave in a risk-averse manner when being watched and attend specifically to eyes when assessing humans’ attentional states. Here, we examined if dogs were slower to steal food in the presence of pictures of eyes compared to flowers. Dogs showed no difference in the latency to steal food between the two conditions. This finding shows that dogs are not sensitive to watching-eyes and is not consistent with a risk-aversion hypothesis for the watching-eye effect.

To help or punish in the face of unfairness: men and women prefer mutually-beneficial strategies over punishment in a sexual selection context

Consistent with a sexual selection account of cooperation, based on female choice, men, in romantic contexts, in general display mutually-beneficial behaviour and women choose men who do so. This evidence is based on a two-choice-architecture (cooperate or not). Here we extend this to include punishment options using a four-choice-architecture ('punishing a transgressor', 'compensating a victim', 'both punishing and compensating' or 'doing nothing'). Both compensation (a self-serving mutually-beneficial behaviour) and self-serving punishment, are associated with positive mate qualities. We test which is preferred by males and chosen by female undergraduates. We further explore effects of trait empathy and political ideology on these preferences. In a series of three studies using a third-party punishment and compensation (3PPC) game we show (Study One), that romantically-primed undergraduate males, express a preference to either 'compensate' or 'both compensate and punish', and undergraduate women find males who 'compensate' or 'compensate and punish' the most attractive (Studies Two and Three). Compensating men are perceived as compassionate, fair and strong by undergraduate women (Study Three). High trait empathy (Studies One and Three) and a left-wing political ideology (Study Three) are associated with a preference for compensation. Thus, self-serving mutually-beneficial behaviour can be preferred over self-serving punishment as a signal of mate quality in undergraduates. Implications for the evolution of cooperation are discussed with respect to sexual selection.

Silence Is Golden. Six Reasons Inhibiting the Spread of Third-Party Gossip

Most of the current literature on gossip describes gossipmongers as incessantly sharing evaluative and valuable information about an absent third party in teams, groups, communities, and organizations. However, potential gossipers can similarly decide not to share what they know, depending on the content, the context, or their relationship with the other actors in the gossip triad. We argue that understanding the reasons why people do not gossip may provide useful insights into individual motives, group dynamics, and collective behaviors. This theoretical contribution first critically surveys the existing gossip literature with the aim of highlighting the conditions under which people might refrain from sharing third party information. We then propose to apply Goal Framing theory as a way to bridge a theory of the micro-foundations of human behavior with an analytical model of the gossip triad that disentangles the various ways through which senders, receivers, and objects of gossip may be interrelated. From a goal framing perspective, most research on gossip illustrates the mechanisms in which the hedonic gratification derived from gossiping is reinforced by gain or normative goals. However, a normative or a gain goal frame can prevent the gossip monger from spreading the information, and we argue that depending on different configurations of frames and relations between actors the perceived costs of sending gossip may be far higher than much of the previous literature suggests.