Render help or stand by? The effect of group size on third-party punishment and its neural mechanisms.

Third-party punishment (TPP) is the punishment that an individual executes on a violator as a third party or observer to maintain social norms. Many studies have provided insights into the neural mechanisms of third-party punishment in group environments. Still, only some studies have focused on the neural mechanisms of third-party punishment in different group sizes. This study used EEG analysis to explore the effects of group size on third-party punishment and its neural activity characteristics from the context of gain and loss. The results show that the punishment rate and amount of the third party in the small group size and loss context were significantly higher than that in the large group size and gain context. EEG results showed that third-party punishment in small groups induced greater P2 than in large groups. In the loss context, the third-party punishment in the large group size induced more negative LNP and activated more theta band activation than in the small group. The results showed that the motivation of the third party to seek a positive reputation in the small size exceeds the balance of its economic interests and tends to punish the violator for maintaining fair norms. The loss context plays a promoting role in this process. However, in the large size, the third-party consideration of its interests was stronger than the willingness to maintain social norms. This study provided neuroscientific evidence for third-party punishment to maintain fair norms in a group environment and further explanations from neuroscience for understanding Indirect Reciprocity Theory.

Receivers' responses are integrated into costly third-party punishment in a way that interacts with the unfairness of allocations.

Costly third-party punishment (TPP) is an effective way to enforce fairness norms and promote cooperation. Recent studies have shown that the third party considers not only the proposer's suggested allocation but also the receiver's response to the allocation, which was typically ignored in traditional TPP studies when making punishment decisions. However, it remains unclear whether and how the varying unfair allocations and receivers' responses are integrated into third-party punishment. The current study addressed these issues at behavioral and electrophysiological levels by employing a modified third-party punishment task involving proposers' highly or moderately unfair allocations and the receivers' acceptance or rejection responses. At the behavioral level, participants punished proposers more often when receivers rejected relative to accepted unfair allocations. This effect was further modulated by the unfairness degree of allocations, indicated by a more pronounced rejection-sensitive effect when participants observed the moderately unfair offers. Electrophysiologically, when the receiver rejected the moderately unfair allocations, a stronger late-stage component P300/LPP, which was considered to be involved in allocations of attention resources, was found. Meanwhile, separated from the P300/LPP, the P200 associated with early attention capture demonstrated a rejection-sensitive effect. Together, in the costly TPP studies, the receiver is typically designated as passive and silent, and her/his responses to unfairness are conventionally ignored. However, our results indicate that except for the proposer's distribution behavior, the receiver's response does have an impact on third-party punishment in a way that interacts with the unfairness of allocations.

The promoting effect of the absence of second-party's punishment power on third-party punishment in maintaining social fairness norms: An EEG hyper-scanning study.

Third-party punishment (TPP) plays an irreplaceable role in maintaining social fairness. Punishment power is a significant area of study within economic games. However, the impact of whether or not the second-party possesses punishment power on TPP remains unexplored. The present study utilizes the high temporal resolution of EEG and time-frequency analysis, intra-barin functional connectivity analysis, inter-brain synchronization (IBS) analysis, and granger causality analysis(GCA) to comprehensively explore the neural mechanism of TPP from the perspective of third-party individual's decision-making and IBS in the real-time social interaction. Time-frequency results found that, the absence of the punishment power activated more theta-band and alpha-band power compare to when second-party has punishment power. When second-party has no punishment power, functional connection results observed stronger functional connectivity in theta band for medium unfair offers between rTPJ and PFC. Dual-brain analysis revealed that when the second-party has no punishment power, there is a significantly higher IBS in the alpha band between the frontal and frontal-central lobes of the second-party and the parietal and parietal occipital lobes of the third-party. GCA results further showed that the direction of IBS from third-party to second-party was significantly stronger than from second-party to third-party. This study demonstrates that the absence of the second-party's punishment power promote TPP, and similar cognitive process of thinking on how to maintain social fairness enhances IBS. The current study emphasizes the influence of punishment power on TPP, broadens the research perspective and contributes crucial insights into maintain social fairness.

Height matters: An EEG study of the relative height disadvantage promoting third-party punishment.

The study employed event-related potential (ERP), time-frequency analysis, and functional connectivity to comprehensively explore the influence of male's relative height on third-party punishment (TPP) and its underlying neural mechanism. The results found that punishment rate and transfer amount are significantly greater when the height of the third-party is lower than that of the recipient, suggesting that male's height disadvantage promotes TPP. Neural results found that the height disadvantage induced a smaller N1. The height disadvantage also evoked greater P300 amplitude, more theta power, and more alpha power. Furthermore, a significantly stronger wPLI between the rTPJ and the posterior parietal and a significantly stronger wPLI between the DLPFC and the posterior parietal were observed when third-party was at the height disadvantage. These results imply that the height disadvantage causes negative emotions and affects the fairness consideration in the early processing stage; the third-party evaluates the blame of violators and makes an appropriate punishment decision later. Our findings indicate that anger and reputation concern caused by height disadvantage promote TPP. The current study holds significance as it underscores the psychological importance of height in males, broadens the perspective on factors influencing TPP, validates the promoting effect of personal disadvantages on prosocial behavior, enriches our understanding of indirect reciprocity theory, and extends the application of the evolution theory of Napoleon complex.

Win-win or lose-lose: Children prefer the form of equality.

In middle childhood, children's sense of fairness further develops, they are willing to pay a cost to maintain equality. Win-win and lose-lose are two forms of equality. Win-win equality refers to both parties maximizing benefits, while lose-lose equality means both parties incurring the maximum loss. Win-win equality allows third party upholding fairness to gain more reputational benefits without the violator being punished, embodying the principle of "benefiting oneself without harming others". On the other hand, lose-lose equality is a more deterrent form of fairness with the violator getting punished, and the third-party might experience a situation of "effort without appreciation." However, the specific form of equality which school-aged children prefer still requires further exploration. Therefore, adopting the dictator game paradigm of third-party punishment, we design two experiments to investigate the fairness preference of first to fourth-grade children when acting as a third party and to clarify patterns of age-related changes. Study 1 (N = 111) explored children's preferred form of fairness under advantageous inequity conditions. Study 2 (N = 122) further examined children's fairness preferences in disadvantageous inequity situations. The findings suggest that when confronted with inequitable distributions, whether rooted in disadvantageous or advantageous inequity, children display a notable tendency to utilize third-party punishment to achieve an equal allocation. Meanwhile, this tendency strengthens as they progress in grade levels. Notably, children consistently manifest a preference for win-win equality, highlighting their inclination towards mutually beneficial outcomes.

Context Modulates Perceived Fairness in Altruistic Punishment: Neural Signatures from ERPs and EEG Oscillations.

Social norms and altruistic punitive behaviours are both based on the integration of information from multiple contexts. Individual behavioural performance can be altered by loss and gain contexts, which produce different mental states and subjective perceptions. In this study, we used event-related potential and time-frequency techniques to examine performance on a third-party punishment task and to explore the neural mechanisms underlying context-dependent differences in punishment decisions. The results indicated that individuals were more likely to reject unfairness in the context of loss (vs. gain) and to increase punishment as unfairness increased. In contrast, fairness appeared to cause an early increase in cognitive control signal enhancement, as indicated by the P2 amplitude and theta oscillations, and a later increase in emotional and motivational salience during decision-making in gain vs. loss contexts, as indicated by the medial frontal negativity and beta oscillations. In summary, individuals were more willing to sanction violations of social norms in the loss context than in the gain context and rejecting unfair losses induced more equity-related cognitive conflict than accepting unfair gains, highlighting the importance of context (i.e., gain vs. loss) in equity-related social decision-making processes.

The shorter a man is, the more he defends fairness: relative height disadvantage promoting third-party punishment-evidence from inter-brain synchronization.

Third-party punishment occurs in interpersonal interactions to sustain social norms, and is strongly influenced by the characteristics of the interacting individuals. During social interactions, height is the striking physical appearance features first observed, height disadvantage may critically influence men's behavior and mental health. Herein, we explored the influence of height disadvantage on third-party punishment through time-frequency analysis and electroencephalography hyperscanning. Two participants were randomly designated as the recipient and third party after height comparison and instructed to complete third-party punishment task. Compared with when the third party's height is higher than the recipient's height, when the third party's height is lower, the punishment rate and transfer amount were significantly higher. Only for highly unfair offers, the theta power was significantly greater when the third party's height was lower. The inter-brain synchronization between the recipient and the third party was significantly stronger when the third party's height was lower. Compared with the fair and medium unfair offers, the inter-brain synchronization was strongest for highly unfair offers. Our findings indicate that the height disadvantage-induced anger and reputation concern promote third-party punishment and inter-brain synchronization. This study enriches research perspective and expands the application of the theory of Napoleon complex.

Enforcement of Fairness Norms by Punishment: A Comparison of Gains and Losses.

Although in everyday life decisions about losses are prevalent (e.g., the climate crisis and the COVID-19 crisis), there is hardly any research on decisions in the loss domain. Therefore, we conducted online experiments with a sample of 672 participants (mostly students), using third-party punishment dictator games (DGs) in the loss domain to explore the impact of losses and punishment threats on the conformity to the fairness norm. Subjects in the treatment condition have to divide a loss of -10 € with the threat of a third-party punishment with different strengths (control: gains, no punishment). Overall, the statistical evidence seems rather weak, but when it comes to losses, subjects are more rational and straightforward with their words and deeds than with gains. Therefore, in the loss domain, subjects are more likely to believe that the fairness norm should be followed, and they subjectively perceive that the others do as well. Furthermore, although dictators' decisions are more selfish in the loss domain, dictators there react more strongly to the punishment threat by reducing their demands than in the gains domain. This holds as long as the punishment threat is strong enough, as judged from a rational perspective.

Voice attractiveness and decision making in third-party punishment.

This study examined the impact of an attractive voice compared to an unattractive voice in an economic game. Results showed that proposers with an attractive voice were perceived as more reasonable in their monetary allocations and were less likely to receive punishment for unfair allocation.

The science of justice: The neuropsychology of social punishment.

The social punishment (SP) of norm violations has received much attention across multiple disciplines. However, current models of SP fail to consider the role of motivational processes, and none can explain the observed behavioral and neuropsychological differences between the two recognized forms of SP: second-party punishment (2PP) and third-party punishment (3PP). After reviewing the literature giving rise to the current models of SP, we propose a unified model of SP which integrates general psychological descriptions of decision-making as a confluence of affect, cognition, and motivation, with evidence that SP is driven by two main factors: the amount of harm (assessed primarily in the salience network) and the norm violator's intention (assessed primarily in the default-mode and central-executive networks). We posit that motivational differences between 2PP and 3PP, articulated in mesocorticolimbic pathways, impact final SP by differentially impacting the assessments of harm and intention done in these domain-general large-scale networks. This new model will lead to a better understanding of SP, which might even improve forensic, procedural, and substantive legal practices.

Group membership and adolescents' third-party punishment: a moderated chain mediation model.

Third-party punishment (TPP) reflects people's social preference for fairness norms and is fundamental to maintaining fairness norms on a large scale. Several empirical studies have shown that the offender's group membership impacts TPP, but the detailed mechanisms have yet to be fully elucidated. The current study used the third-party punishment game task to explore the relationship between group membership, perceived unfairness, anger, and adolescents' TPP. A total of 306 teenagers aged 12 to 15 were chosen as subjects through cluster sampling. The results showed that group membership (classmate vs. stranger) and gender can affect adolescents' TPP together, which manifests as adolescents enacting significantly harsher punishments on strangers than on classmates, especially for boys. Group membership indirectly affects TPP through the mediating effects of perceived unfairness, anger and through a chain mediation of perceived unfairness and anger. Moreover, gender positively moderate the relationship between group membership and perceived unfairness. Specifically, group membership significantly affects boys' perceived unfairness, but cannot predict girls' perceived unfairness. The above results can be used to guide adolescents toward appropriate justice concepts and moral awareness, thus enhancing TPP.

Third-party punishers who express emotions are trusted more.

Third party punishment (TPP) is thought to be crucial to the evolution and maintenance of human cooperation. However, this type of punishment is often not rewarded, perhaps because punishers' underlying motives are unclear. We propose that the expression of moral emotions could solve this problem by advertising such motives. In each of three experiments (n = 1711), a third-party punishment game was followed by a trust game. Third parties expressed anger or disgust instead of, or in addition to, financial punishment. Results showed that third parties who expressed these emotions were trusted more than those who didn't express (Experiment 1), and more than those who financially punished (Experiment 2). Moreover, third parties who expressed while financially punishing were trusted more than those who punished without expressing (Experiment 3). Findings suggest that emotion expression might play a role in the evolution and maintenance of cooperation by facilitating TPP.

Punishment in the public goods game is evaluated negatively irrespective of non-cooperators' motivation.

The evolution of human cooperation toward strangers remains puzzling. While the punishment of non-cooperators is a possible explanation, whether punishments can help cooperation evolve depends on how people evaluate punishers. Thus, it is of vital importance to elucidate the perception of punishers. Previous studies have found that punishment is evaluated differently in different contexts; punishers are negatively and positively evaluated in the public goods game with punishment (PGG-P) and in the third-party punishment game (TPP), respectively. To disentangle the mixed evidence, our research focused on motivations for non-cooperation and examined whether different motivations for non-cooperation could explain the inconsistent findings. We hypothesized that people positively evaluate punishers when they punish those who non-cooperated to exploit others (greed), e.g., in a TPP situation. Contrastingly, people negatively evaluate punishers when they punish those who non-cooperated to avoid exploitation (fear), e.g., in a PGG-P situation. If so, in either game, punishers would be evaluated positively in situations where greed dominates, and negatively in situations where fear dominates the non-cooperation motivation. To test this, we conducted two online experiments with hypothetical scenarios in which the decision-making order was used to manipulate the motivations of non-cooperators. The results of Study 1 (N = 240) using only PGG-P and Study 2 (N = 602) using both PGG-P and TPP showed that the non-cooperation motivation did not have a significant effect on the evaluations of punishers and non-punishers. Punishers (vs non-punishers) were evaluated negatively in PGG-P and positively in TPP regardless of the decision-making order of non-cooperation. We discussed the role of higher-order information in the evaluation of punishment.

Group bias under uncertain environment: A perspective of third-party punishment.

Third-party punishment (TPP) effectively promotes social cooperation and maintains social norms in which equity plays a decisive role. When third-party and players are affiliated with different groups, there are two distinct phenomena-in-group favoritism (IGF) and black sheep effect (BSE)-in a certain environment. Equity loses its function as a benchmark when the environment is uncertain (de Kwaadsteniet et al., 2013). Thus, we hypothesized that individuals have a stronger IGF because there is more room for interpretations of their behaviors when an uncertain environment results in ambiguous social norms. We utilized a common resource dilemma (CRD) to manipulate the environmental uncertainty by varying the range of the resource size: a certain environment is represented by a resource size of fixed tokens (i.e., 500 tokens) and an uncertain one is represented by that of 300 to 700 tokens. Additionally, group affiliation is manipulated by the alumni relation between the third-party and players. The present study revealed that the uncertain environment led to stricter costly punishment. The experiment confirms the IGF rather than the BSE. We found boundary conditions between IGF and out-group derogation (OGD). When the players' harvest was not obviously violated, the size of TPP for a control group without group affiliation manipulation anchored those of the in-group and OGD occurred. Opposite, when the harvest was obviously violated, the size of TPP for the control group anchored those of the out-group and IGF occurred. The gender of the third-party affects its decision to punish, with men anchoring the control group's punishment to the in-group and showing OGD, whereas women anchoring the control group's punishment to the out-group and showing IGF.

Emergence of specialized third-party enforcement.

The question of how cooperation evolves and is maintained among nonkin is central to the biological, social, and behavioral sciences. Previous research has focused on explaining how cooperation in social dilemmas can be maintained by direct and indirect reciprocity among the participants of the social dilemma. However, in complex human societies, both modern and ancient, cooperation is frequently maintained by means of specialized third-party enforcement. We provide an evolutionary-game-theoretic model that explains how specialized third-party enforcement of cooperation (specialized reciprocity) can emerge. A population consists of producers and enforcers. First, producers engage in a joint undertaking represented by a prisoner's dilemma. They are paired randomly and receive no information about their partner's history, which precludes direct and indirect reciprocity. Then, enforcers tax producers and may punish their clients. Finally, the enforcers are randomly paired and may try to grab resources from each other. In order to sustain producer cooperation, enforcers must punish defecting producers, but punishing is costly to enforcers. We show that the threat of potential intraenforcer conflict can incentivize enforcers to engage in costly punishment of producers, provided they are sufficiently informed to maintain a reputation system. That is, the "guards" are guarded by the guards themselves. We demonstrate the key mechanisms analytically and corroborate our results with numerical simulations.

Electrophysiological correlates of third-party punishment: ERP study.

Human societies benefit from social norms that increase cooperation and support social order. Hence, the understanding of effective mechanisms enforcing norms is crucial. One of such mechanisms is "third-party punishment" (TPP) - a form of social punishment that could be delivered by a third-party, not directly affected by the actions of the norm violator. Previous electrophysiological studies (ERP) reported that perceived violations of norms evoked the medial frontal negativity in third-parties. The current study further probed the link between the medial frontal negativity (MFN) and actual TPP of norm violation, as it was not shown directly before. Participants played a dictator game as third-parties, being able to select different levels of punishment of an unfair violator's decisions. We replicated previous findings and showed the amplitude of the MFN correlated with the intensity of TPP (Fz, r = -0.516, p = 0.034, FCz, r = -0.509; p = 0.037). Overall, our findings further support the direct link between the MFN and the intensity of TPP.

Children endorse deterrence motivations for third-party punishment but derive higher enjoyment from compensating victims.

Children's punishment behavior may be driven by both retribution and deterrence, but the potential primacy of either motive is unknown. Moreover, children's punishment enjoyment and compensation enjoyment have never been directly contrasted. Here, British, Colombian, and Italian 7- to 11-year-old children (N = 123) operated a Justice System in which they viewed different moral transgressions in Minecraft, a globally popular video game, either face-to-face with an experimenter or over the internet. Children could respond to transgressions by punishing transgressors and compensating victims. The purpose of the system was framed in terms of retribution, deterrence, or compensation between participants. Children's performance, endorsement, and enjoyment of punishment and compensation were measured, along with their endorsement of retribution versus deterrence as punishment justifications, during and/or after justice administration. Children overwhelmingly endorsed deterrence over retribution as their punishment justification irrespective of age. When asked to reproduce the presented frame in their own words, children more reliably reproduced the deterrence frame rather than the retribution frame. Punishment enjoyment decreased while compensation enjoyment increased over time. Despite enjoying compensation more, children preferentially endorsed punishment over compensation, especially with increasing age and transgression severity. Reported deterrent justifications, superior reproduction of deterrence framing, lower enjoyment of punishment than of compensation, and higher endorsement of punishment over compensation together suggest that children felt that they ought to mete out punishment as a means to deter future transgressions. Face-to-face and internet-mediated responses were not distinguishable, supporting a route to social psychology research with primary school-aged children unable to physically visit labs.

To help or not: negative aging stereotypes held by younger adults could promote helping behaviors toward older adults.

Aging stereotypes affect older adults' behaviors, however, it is unclear whether and how (negative) aging stereotypes influence younger adults' behaviors toward older adults. Two possibilities arose, such that aging stereotypes would reduce helping behaviors according to TMT and SIT; while based on the BIAS map, we would expect the opposite. The present study aimed to further compare the two possibilities by examining the effect of negative aging stereotypes on younger adults' helping behaviors, and testing which theory would fit the data better. In a cross-sectional study (Study 1), 112 Chinese younger adults (M = 22.67, SD = 2.56) were recruited. Aging stereotypes were measured by the Ambivalent Ageism Scale and the abbreviated ageism questionnaire. And their prosocial behaviors were measured by the modified third-party punishment task. The results revealed that high benevolent ageism would increase helping behaviors toward older adults. In the following experiment with aging stereotype priming (positive, neutral vs. negative) among 130 Chinese younger adults (M = 26.82, SD = 3.70), we confirmed the influence of negative aging stereotypes on prosocial behaviors measured by both third-party punishment and Social Value Orientation tasks. Study 2 further demonstrated that pity might mediate the association between negative aging stereotypes and behaviors. Our results indicated that younger adults' negative aging stereotypes could increase their prosociality toward older adults through pity in line with BIAS maps. It also had significant theoretical and practical implications for future research. For example, with more education and intergenerational contact in younger generation which could evoke pity feelings for older adults, could help to build harmonious intergenerational relations. Supplementary Information: The online version contains supplementary material available at 10.1007/s12144-023-04371-0.

Time Pressure Weakens Social Norm Maintenance in Third-Party Punishment.

Decision-making under time pressure may better reflect an individual's response preference, but few studies have examined whether individuals choose to be more selfish or altruistic in a scenario where third-party punishment is essential for maintaining social norms. This study used a third-party punishment paradigm to investigate how time pressure impacts on individuals' maintenance of behavior that follows social norms. Thirty-one participants observed a Dictator Game and had to decide whether to punish someone who made what was categorized as a high unfair offer by spending their own Monetary units to reduce that person's payoff. The experiment was conducted across different offer conditions. The study results demonstrated that reaction times were faster under time pressure compared with no time pressure. Time pressure was also correlated with less severe punishment. Specifically, participants were less likely to punish the dictator under time pressure compared with no time pressure when the offer was categorized as a high unfair. The findings suggested that individuals in these game conditions and under time pressure do not overcome their pro-selves and that time pressure weakens an individual's willingness to punish high unfair offers.

Doesn't everybody jaywalk? On codified rules that are seldom followed and selectively punished.

Rules are meant to apply equally to all within their jurisdiction. However, some rules are frequently broken without consequence for most. These rules are only occasionally enforced, often at the discretion of a third-party observer. We propose that these rules-whose violations are frequent, and enforcement is rare-constitute a unique subclass of explicitly codified rules, which we call 'phantom rules' (e.g., proscribing jaywalking). Their apparent punishability is ambiguous and particularly susceptible to third-party motives. Across six experiments, (N = 1440) we validated the existence of phantom rules and found evidence for their motivated enforcement. First, people played a modified Dictator Game with a novel frequently broken and rarely enforced rule (i.e., a phantom rule). People enforced this rule more often when the "dictator" was selfish (vs. fair) even though the rule only proscribed fractional offers (not selfishness). Then we turned to third person judgments of the U.S. legal system. We found these violations are recognizable to participants as both illegal and commonplace (Experiment 2), differentiable from violations of prototypical laws (Experiments 3) and enforced in a motivated way (Experiments 4a and 4b). Phantom rule violations (but not prototypical legal violations) are seen as more justifiably punished when the rule violator has also violated a social norm (vs. rule violation alone)-unless the motivation to punish has been satiated (Experiment 5). Phantom rules are frequently broken, codified rules. Consequently, their apparent punishability is ambiguous, and their enforcement is particularly susceptible to third party motives.