Social value orientation modulates fairness processing during social decision-making: evidence from behavior and brain potentials

Altruistic or fair? The influence of empathy on third-party punishment: an event-related potential study

Although most individuals strongly prefer social fairness and punish behaviours that violate fairness norms, recent psychological studies have shown that empathy towards 'perpetrators' who violate fairness norms can affect people's fairness decision-making, resulting in tolerance for unfair behaviour, even as direct 'victims' of unfair behaviour. However, in real life, people more often view unfair events from a third-party perspective, and little is known about how empathy affects fairness decisions by third parties whose self-interests are not threatened and their neurocognitive mechanisms. The present study examined effects of empathy directed towards a 'perpetrator' on third-party punishment using event-related potentials. The results suggest that, in the nonempathy condition, unfair offers induced stronger unfairness aversion in third-party decision makers and increased motivation and cognitive resource investment to alleviate this negative emotion compared to fair offers, reflecting the greater amplitude differences of fairness effects on the anterior N1 component, medial frontal negative, and smaller late positive components in the nonempathy condition. However, in the empathy condition, the differential impact of the fairness effect disappeared. These findings reveal the neural basis for trade-offs between altruistic and fairness motives in third-party fairness decision-making processes involving empathy.

Neural correlates of how egoistic, altruistic, and mixed motivations modulate the influence of self-deception on deceptive behavior

Using event-related potentials, this study investigated the interplay between self-deception and varying motivations in influencing deceptive behavior. Participants in either the self-deception or nonself-deception condition were instructed to make deceptive decisions under different motivational contexts. Behavioral responses and neural activity were recorded throughout the decision-making process. Behaviorally, there were no significant differences in deception proportions between the self-deception and nonself-deception conditions under egoistic or mixed motivations. However, under altruistic motivation, participants in the self-deception condition engaged in more deceptive behavior compared to those in the nonself-deception condition. Event-related potential results revealed no significant differences in P2 and N2 amplitudes between the self-deception and nonself-deception conditions under egoistic or mixed motivations. However, under altruistic motivation, the self-deception condition was associated with reduced P2 amplitudes and more negative N2 amplitudes relative to the nonself-deception condition. Additionally, no significant interaction in P3 amplitudes was found between self-deception and different motivations. These findings suggest that the effect of self-deception on deceptive behavior is modulated by different motivations. Specifically, egoistic or mixed motivations might be associated with a self-serving tendency in deceptive behavior, while altruistic motivation appeared to enhance deceptive behavior in the self-deception condition, potentially to foster a prosocial image.

Relative social status alters the synchrony of attribute integration in altruistic decisions

Social status, which represents the relative dominance structure in societies, forms the backdrop against which most social decisions are made. Effective social decision-making demands flexible integration of decision attribute weight (importance of an attribute) and attribute latency (when attributes start to affect decisions). However, current understanding of how attribute weight and latency are influenced by relative social status is limited. In three experiments, we dynamically manipulated subjects' relative social status before they engaged in an altruistic decision task and found that their altruistic behavior was better explained by a time-varying drift diffusion model, in which relative social status selectively modulated attribute latency but not attribute weights. Furthermore, prosocial subjects exhibited higher sensitivity to attribute latency in response to changes in relative social status compared with individualistic subjects. Our results introduce a new dimension to the computational mechanisms underlying the intricate interplay between relative social status and attribute integration.

The impact of inequality on social value orientation: an eye-tracking study

Introduction

Researchers have developed the social value orientation (SVO) framework to describe prosocial tendencies. However, existing tools for measuring SVO lack sufficient attention to the effect of option inequality, driven by the inequality-aversion motive. In this research, we conducted an eye-tracking experiment to compare the traditional SVO measure with the inequality-controlled condition, investigating how it influences estimated SVO values and underlying process mechanisms.

Methods

A within-subjects eye-tracking experiment was conducted with 65 university students recruited from a university's human subjects pool. Participants received 20 yuan (RMB; approximately US $2.9) in cash for their participation.

Results

SVOs were lower in the inequality-controlled condition than in the traditional SVO measure. Information processing, including complexity, depth, and direction, differed when fairness was controlled. The predictive effect of relative time advantage was also enhanced under controlled inequality conditions. In addition, the predictive effect of relative time advantage was stronger when controlling for option inequality, suggesting that controlling for option inequality enhances bottom-up information processing.

Discussion

These findings suggest that traditional SVO measures may overestimate prosocial tendencies due to a lack of inequality control. The study highlights the role of fairness evaluation in SVO assessments and provides insights into the cognitive mechanisms underlying prosocial decision-making, offering guidance for future SVO measurements.

Neural correlates of reciprocity bias: social debts modulate unfairness perception of violation during third-party observation

The phenomenon of beneficiaries ignoring benefactors' violations, ranging from everyday favors to bribes, is widespread yet lacks targeted theoretical and empirical attention. We propose a conceptual framework that includes "social debt" and "reciprocity bias," where "social debt" is defined as information about benefits bestowed by benefactors and "reciprocity bias" as the influence of social debt on beneficiaries' perceptions and decisions in situations involving the benefactor. To investigate this bias in moral perception and its cognitive-neural mechanisms, we manipulated three levels of social debt (none, less, more) by varying the amount of unasked benefits that benefactors bestowed upon participants. Participants then observed the distributor's fair or unfair allocation of resources to another person, while their electroencephalography (EEG) was recorded. Results indicate that more (vs. none/less) social debt reduces perceptions of unfairness toward benefactors' violations and enhances fairness perceptions of their norm adherence. This was, accompanied by the diminished fairness effect on fronto-centered P2 and a reversal fairness effect on the power of theta oscillations (4 to 7 Hz). These findings support a multilevel reciprocity bias in fairness perception, suggesting that strong social debt may heighten concern for benefactor's interests and increase the adaptive value of their violations at the cognitive-neural level.

Good luck or bad luck? The influence of social comparison on risk-taking decision and the underlying neural mechanism

The present study aimed to investigate the impact of social comparison on risk-taking behaviors and the neural underpinnings within a competitive context. Participants who thought they were playing against a stranger in a gambling task were actually playing against a programmed computer. Eighty-eight college students were assigned to one of three comparison conditions (downward, upward, and parallel) by varying the probability of gain. Behavioral results showed that disadvantage led to increased risk-taking. Event-related potential data analyses showed, in the parallel comparison condition, a significantly larger Feedback-Related Negativity (FRN) was induced by the self's safe decision than the risky decision and by loss rather than gain. However, in the upward and downward comparison conditions, larger FRN emerged solely in response to the loss of risky rather than safe decisions. On the P3 component, participants in the upward comparison condition showed no significant difference in response to their gain or loss, while the other two conditions did. The highest P3 amplitude, delta/theta power, and aperiodic activity were found in the closely matched condition. Finally, in the downward comparison condition, a stronger delta/theta power was correlated with a less risky decision. Overall, the findings indicate that parity heightens emotional arousal and engages more cognitive resources.

Distributive fairness during the transition to adolescence: The role of peer comparison and social value orientation

Combining the dictator game (DG) and the ultimatum game (UG), this study recruited 546 Chinese children (321 boys, aged 9-12 years) as distributors, and found that both peer comparison and social value orientation (SVO) significantly influenced children's distributive fairness from late childhood to early adolescence. Results showed that as the unfairness of peer proposals increased, participants decreased the amount of gold coins distributed to the receiver in both tasks, revealing a peer comparison effect. This effect was more pronounced for adolescents than for children in both tasks. In addition, participants' fair distribution behaviors in the DG showed a three-way interaction effect of SVO, grade, and peer comparison. Specifically, for proselfs, children were not influenced by peers and consistently proposed self-interested distributions, whereas adolescents exhibited a peer comparison effect; for prosocials, both children and adolescents were influenced by peers, but children decreased the amount of their distributions only when they saw peers make extremely unfair distributions, whereas adolescents decreased the amount of their distributions when they saw peers make both mildly and extremely unfair distributions. This study highlights the importance of social environment and personal trait in shaping children's fair distribution behavior during the transition from late childhood to early adolescence.

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.

Neural mechanisms of fairness decision-making: An EEG comparative study on opportunity equity and outcome equity

Social equity consists of opportunity equity and outcome equity, where outcome equity refers to the equitable distribution of resource, while opportunity equity refers to equivalent sets of opportunities to obtain a satisfactory outcome, ensuring equality in expected payoffs rather than the actual payoffs. Previous studies showed the existence of inequity aversion for opportunity inequality and identified some differences between opportunity equity and outcome equity in the behavior pattern of evaluation and reaction processes. However, the commonalities and distinctions in brain activity during the fairness decision-making of opportunity equity and outcome equity remain unclear. Our study used a modified version of the ultimatum game (UG) and the classic UG, and recorded electroencephalogram (EEG) data to investigate underlying neural mechanisms of fairness decision-making of opportunity equity and outcome equity. The EEG results revealed that both shared the same components of the P300 and delta bands associated with reward processing. Compared to outcome equity, opportunity equity did not identify conflict-related medial frontal negativity (MFN) and theta bands, but showed differences in the P2 and beta bands. Moreover, we used a computational modeling approach to estimate the utility for each trial, and found that larger P2 amplitudes were associated with lower utility in opportunity distribution, while larger P300 amplitudes were associated with higher utility in outcome distribution. Our findings provide electrophysiological evidence for the existence of opportunity equity and shed light on the cognitive processing disparities between opportunity equity and outcome equity. These results not only validate and expand the theory of inequality aversion but also empirically support the targeted resolution of social inequalities in various contexts.

Interpersonal distance affects advisors' responses to feedback on their advice: Evidence from event-related potentials

Advisors typically receive two types of feedback: whether their advice is accepted and benefits the advisee. However, the effect of interpersonal distance on advisors' feedback responses remains unexplored. Therefore, to examine this association, we used an advice-giving task in which participants acted as advisors to either friends or strangers through event-related potentials (ERP). Participants received feedback reflecting whether their advice was accepted or rejected and the advisee's outcome (gains or losses). Participants' electroencephalograms were recorded when receiving feedback. Results revealed that rejections from friends elicited stronger feedback-related negativity (FRN) than acceptances from friends. Furthermore, acceptances from friends triggered larger late positive components (LPCs) than rejections from friends. No such effects were observed when the advisee was a stranger. Moreover, a stronger FRN was observed for losses than gains when strangers accepted the advice; however, this difference was not observed when strangers rejected the advice. In addition, friends' gains elicited a larger P300 than losses, regardless of whether friends accepted the advice; however, for strangers, this P300 difference was observed only when the advice was accepted. When strangers accepted the advice, gains elicited larger LPCs than losses; however, this difference was not observed when strangers rejected the advice. These results revealed that the interpersonal distance between people affected how they responded to feedback on advice. This was demonstrated by the neural responses related to expectations, motivational significance, and emotional arousal. It also suggests that the psychological processes by which interpersonal distance influences feedback processing change over the stages.

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 interplay between the proposer's role model and moral behavior modulates proposal processing in the Ultimatum Game: An ERP study

Economic decision-making plays a paramount role in both individual and national interests. Individuals have fairness preferences in economic decision-making, but a proposer's moral-related information may affect fairness considerations. In prior ERP studies, researchers have suggested moral identity influences fairness preferences in the Ultimatum Game (UG), but there are discrepancies in the results. Furthermore, whether role models (individuals whom someone else looks to help decide suitable behaviors), who can modulate people's moral standards, can affect fairness concerns in UG is still understudied. To address the questions, we selected the moral-related statements by eliminating those with illegal information and employed the ERP technique to explore whether the interplay of the proposer's role model and moral-related behavior influenced fairness processing in the modified UG and the corresponding neural mechanisms. We mainly found that the aforementioned interaction effect on proposal considerations in UG could be mirrored in both rejection rates and P300 variations. The results demonstrate that the interaction between the proposer's role model and moral behavior can modulate fairness concerns in UG. Our current work provides new avenues for elucidating the time course of the influencing mechanism of fair distributions in complicated social environments.

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.

Social observation modulates the influence of socioeconomic status on pro-environmental behavior: an event-related potential study

Understanding the psychological antecedents of socioeconomic status (SES) on pro-environmental behavior is crucial for effectively encouraging individuals from different socioeconomic backgrounds to address environmental issues. Previous research has separately examined the influence of SES and social observation on pro-environmental behavior. However, little is known about whether social observation moderates the influence of SES on pro-environmental behavior, and the underlying neurophysiological mechanisms remain uncharacterized. Using event-related potential (ERPs), we adopted the green purchase paradigm and manipulated subjective SES, to examine whether the influence of SES on pro-environmental behavior is moderated by social observation. The behavioral results revealed that individuals of high SES tended to purchase more eco-friendly products under the observable condition than those in the non-observable condition. The ERP results revealed that participants with high SES exhibited more negative N2 and N400 amplitude during environmental decisions in the non-observable condition than in the observable condition, indicating that high SES individuals experience less cognitive conflict during environmental decisions, which may reflect the attenuated cost-benefit trade-off due to reputational incentives in the presence of observers. Additionally, individuals with high SES exhibited greater reputational motivation when observed, as indicated by larger P3 amplitude. However, these differences were not observed among individuals with low SES. These findings suggest that SES is associated with distinct psychological and behavioral differences in pro-environmental behavior, moderated by social observation, evident across both the early and later stages of environmental decisions in the brain.

Are Deaf College Students More Sensitive to Unfair Information? Evidence from an ERP Study

To better understand the individual differences in fairness, we used event-related potentials (ERPs) to explore the fairness characteristics of deaf college students through the ultimatum game task. Behaviorally, the significant main effect of the proposal type was found, which meant both deaf and hearing college students showed a lower acceptance rate for the more unfair proposal. Interestingly, we found a significant interaction between group and proposal type in the early stage (N1). Moreover, in the deaf college group, N1 (induced by moderately and very unfair proposals) was significantly larger than that of fair proposals. However, we found that deaf college students had smaller amplitudes on P2 and P3 than hearing college students. These results suggested that deaf college students might pursue more equity strongly so they are more sensitive to unfair information in the early stage. In a word, we should provide more fair allocations for deaf college students in our harmonious society.

High- and low-social-anxiety individuals process the outcomes of ability comparisons differently: an event-related potential study

Individuals engage in upward or downward comparisons with superiors or inferiors, respectively. Social comparison is associated with social anxiety. Utilizing event-related potentials, we investigated how individuals with high social anxiety (HSA) and low social anxiety (LSA) evaluate self- versus other-outcomes in upward and downward comparison contexts. We found significant valence effects of self- or other-outcomes on feedback-related negativity (FRN) and P300 for both groups, with loss inducing larger FRN and smaller P300 than gain. In the early stage, the valence effect of other-outcomes was significant when LSA participants gained money, but not when they lost money, revealing a social comparison effect on FRN. Conversely, this valence effect was significant whether HSA participants gained or lost money. At the late stage, the valence effect of other-outcomes was significant when HSA or LSA participants gained money but not when they lost, revealing social comparison effects on the P300. Notably, only the social comparison effect in the LSA group was further moderated by comparison direction. These findings suggest that LSA participants engaged in social comparison throughout all evaluation stages, whereas HSA participants started at the late stage. Moreover, LSA participants were more sensitive to different comparison directions in the late stage.

Proposer's moral identity modulates fairness processing in the ultimatum game: Evidence from behavior and brain potentials

Economic decision-making is pivotal to both human private interests and the national economy. People pursue fairness in economic decision-making, but a proposer's moral identity can influence fairness processing. Previous ERP studies have revealed that moral identity has an effect on fairness considerations in the Ultimatum Game (UG), but the findings are inconsistent. To address the issue, we revised the moral-related sentences and used the ERP technique to measure the corresponding neural mechanism. We have observed that the fairness effect in UG can be mirrored in both MFN and P300 changes, whereas the moral identity effect on fairness in UG can be reflected by MFN but not P300 changes. These findings indicate that the moral identity of the proposer can modulate fairness processing in UG. The current study opens new avenues for clarifying the temporal course of the relationship between the proposer's moral identity and fairness in economic decision-making, which is beneficial for understanding the influencing mechanism of fairness processing and fair allocations in complex social contexts.

Belief Updating during Social Interactions: Neural Dynamics and Causal Role of Dorsomedial Prefrontal Cortex

In competitive interactions, humans have to flexibly update their beliefs about another person's intentions in order to adjust their own choice strategy, such as when believing that the other may exploit their cooperativeness. Here we investigate both the neural dynamics and the causal neural substrate of belief updating processes in humans. We used an adapted prisoner's dilemma game in which participants explicitly predicted the coplayer's actions, which allowed us to quantify the prediction error between expected and actual behavior. First, in an EEG experiment, we found a stronger medial frontal negativity (MFN) for negative than positive prediction errors, suggesting that this medial frontal ERP component may encode unexpected defection of the coplayer. The MFN also predicted subsequent belief updating after negative prediction errors. In a second experiment, we used transcranial magnetic stimulation (TMS) to investigate whether the dorsomedial prefrontal cortex (dmPFC) causally implements belief updating after unexpected outcomes. Our results show that dmPFC TMS impaired belief updating and strategic behavioral adjustments after negative prediction errors. Taken together, our findings reveal the time course of the use of prediction errors in social decisions and suggest that the dmPFC plays a crucial role in updating mental representations of others' intentions.

Observing heroic behavior and its influencing factors in immersive virtual environments

Studying heroism in controlled settings presents challenges and ethical controversies due to its association with physical risk. Leveraging virtual reality (VR) technology, we conducted a three-study series with 397 participants from China to investigate heroic actions. Participants unexpectedly witnessed a criminal event in a simulated scenario, allowing observation of their tendency to physically intercept a thief. We examined situational factors (voluntariness, authority, and risk) and personal variables [gender, impulsivity, empathy, and social value orientation (SVO)] that may influence heroism. Also, the potential association between heroism and social conformity was explored. In terms of situational variables, voluntariness modulated participants' tendency to intercept the escaping thief, while perceived risk demonstrated its impact by interacting with gender. That is, in study 3 where the perceived risk was expected to be higher (as supported by an online study 5), males exhibited a greater inclination toward heroic behavior compared to females. Regarding other personal variables, the tendency to engage in heroic behavior decreased as empathy levels rose among males, whereas the opposite trend was observed for females. SVO influenced heroic behavior but without a gender interaction. Finally, an inverse relationship between heroism and social conformity was observed. The robustness of these findings was partly supported by the Chinese sample (but not the international sample) of an online study 4 that provided written descriptions of VR scenarios, indicating cultural variations. These results advance insights into motivational factors influencing heroism in the context of restoring order and highlight the power of VR technology in examining social psychological hypotheses beyond ethical constraints.

Impact of Empathic Concern on Prosocial Behavior in Gain and Loss Contexts: Evidence from Event-Related Potential

This study employs event-related potential (ERP) to examine the impact of empathic concern on prosocial decision-making with costs in both gain and loss contexts. In this experiment, participants can choose between two types of lottery tickets and pay lottery money to help the target person gain more money or lose less money. The behavioral results showed that regardless of the context of the decision (financial loss or gain), participants tended to help individuals who had induced high empathic concern. ERP results show that compared to the low-empathic-concern condition, the high-empathic-concern condition induced greater P3 amplitude in the gain context. However, this change in P3 amplitude caused by empathic concern did not occur in the context of loss. These findings indicate that empathic concern has different psychological mechanisms that moderate prosocial behavior in gain and loss contexts.

Same allocation proposed by an individual or a group elicits distinct responses: Evidence from event-related potentials and neural oscillation

People tend to perceive the same information differently depending on whether it is expressed in an individual or a group frame. It has also been found that the individual (vs. group) frame of expression tends to lead to more charitable giving and greater tolerance of wealth inequality. However, little is known about whether the same resource allocation in social interactions elicits distinct responses depending on proposer type. Using the second-party punishment task, this study examined whether the same allocation from different proposers (individual vs. group) leads to differences in recipient behavior and the neural mechanisms. Behavioral results showed that reaction times were longer in the unfair (vs. fair) condition, and this difference was more pronounced when the proposer was the individual (vs. group). Neural results showed that proposer type (individual vs. group) influenced early automatic processing (indicated by AN1, P2, and central alpha band), middle processing (indicated by MFN and right frontal theta band), and late elaborative processing (indicated by P3 and parietal alpha band) of fairness in resource allocation. These results revealed more attentional resources were captured by the group proposer in the early stage of fairness processing, and more cognitive resources were consumed by processing group-proposed unfair allocations in the late stage, possibly because group proposers are less identifiable than individual proposers. The findings provide behavioral and neural evidence for the effects of "individual/group" framing leading to cognitive differences. They also deliver insights into social governance issues, such as punishing individual and/or group violations.

The impact of social hierarchies on neural response to feedback evaluations after advice giving

Advisors generally evaluate advisee-relevant feedback after advice giving. The response to these feedback-(1) whether the advice is accepted and (2) whether the advice is optimal-usually involves prestige. Prior literature has found that prestige is the basis by which individuals attain a superior status in the social hierarchy. However, whether advisors are motivated to attain a superior status when engaging in advice giving remains uncharacterized. Using event-related potentials, this study investigates how advisors evaluate feedback after giving advice to superior (vs. inferior) status advisees. A social hierarchy was first established based on two advisees (one was ranked as superior status and another as inferior status) as well as participants' performance in a dot-estimation task in which all participants were ranked as medium status. Participants then engaged in a game in which they were assigned roles as advisors to a superior or inferior status advisee. Afterward, the participants received feedback in two phases. In Phase 1, participants were told whether the advisees accepted the advice provided. In Phase 2, the participants were informed whether the advice they provided was correct. In these two phases, when the advisee was of superior status, participants exhibited stronger feedback-related negativity and P300 difference in response to (1) whether their advice was accepted, and (2) whether their advice was correct. Moreover, the P300 was notably larger when the participants' correct advice led to a gain for a superior-status advisee. In the context of advice giving, advisors are particularly motivated to attain a superior status when the feedback involving social hierarchies, which is reflected in higher sensitivity to feedback associated with superior status advisees at earlier and later stages during feedback evaluations in brains.

The influence of altruistic personality, interpersonal distance and social observation on prosocial behavior: An event-related potential (ERP) study

The psychological mechanisms that high and low altruists exhibit in different contexts remain unknown. This study examined the underlying mechanisms of the effect of altruistic personality, social observation, and interpersonal distance on prosocial behavior using event-related potentials (ERPs). Participants with high and low altruism were asked to make prosocial or non-prosocial choices toward different interpersonal distances (friends, acquaintances, or strangers) under the (non)observer condition. The electrophysiological responses to the choice stimuli were simultaneously recorded. The behavioral results demonstrated that high altruists had more prosocial choices, and these choices were unaffected by interpersonal distance and social observation. However, low altruists made more prosocial choices toward friends and acquaintances under the observer than nonobserver conditions, whereas their prosocial choices toward strangers showed no difference. The ERP results demonstrated that low altruists showed more negative N2 when the choice stimuli were toward strangers and acquaintances or under the nonobserver condition. Furthermore, low altruists showed larger P3 under the observer than nonobserver conditions when the choice stimuli were toward friends and acquaintances, while this difference was absent when the choice stimuli were toward strangers. However, for high altruists, no effect of interpersonal distance and social observation was observed in N2 and P3. These results suggest that the prosocial behavior of low altruists is mainly driven by reputational incentives, whereas high altruists are primarily motivated by concern about the well-being of others. Our findings provide insights into the prosocial behavior of high and low altruists in different contexts and support the empathy-altruism hypothesis.

The role of procedural justice and risk preference-based mechanisms in acceptance of public policy

The current study examines the relationship between procedural justice and acceptance of public policy, the mediating effect of uncertainty as well as the moderating effect of risk preference in this relationship. Study 1 conducted a questionnaire survey on 154 residents from Beijing. The results showed that risk preference moderated the effect of procedural justice on acceptance of public policy. Accordingly, Study 2 conducted a scenario experiment on 136 college students from Beijing to examine the mediating role of uncertainty, while retesting the moderating mechanism of risk preference in more detail. Results showed that risk preference significantly moderated the effect of procedural justice on acceptance of public policy. Specifically, uncertainty was more negatively associated with acceptance of public policy among the risk-averse individuals than risk-seeking individuals. Risk preference indirectly moderated the relationship between procedural justice and acceptance of public policy by moderating the relationship between uncertainty and acceptance of public policy.

Which is More Important, Proposer Identity or Allocation Motive? Event-Related Potential in Economic Decision-Making

Purpose

Most studies have supported the view that individuals prefer to reward the in-group and discriminate against the out-group in response to unfair offers in the Ultimatum Game. However, the current study advanced a different view, that is, the "black sheep effect", in which in-group members were punished more severely compared with out-group members. This study aimed to incorporate proposer identity and allocation motive as possible explanations for offer rejection.

Methods

In the current study, the in-group and out-group identities were distinguished by their health condition, and the allocation motive was defined according to its benefit maximization. With a total of 89 healthy college student participants, a mixed design of 2 (proposer identity: out-group vs in-group) × 2 (allocation motive: selfish vs random) × 2 (offer type: unfair vs fair) was used in the Ultimatum Game. Event-related potential (ERP) technology was used, and ERPs were recorded while participants processed the task.

Results

The behavioral result showed that the "black sheep effect" was found on the fair offer when a random allocation motive was used. Our ERP result suggested that feedback-related negativity (FRN) and P300 were modulated by proposer identity but not by allocation motive. However, the allocation motive interacted with proposer identity affecting FRN and P300 when the fair offer was proposed.

Conclusion

These findings demonstrated that the "black sheep effect" was related to the experience of the out-group member, such as disadvantage or distress, but it was also modulated by allocation motive. Meanwhile, the out-group (depressed college students) captured more attention because they violated individual expectations, according to the P300. This finding plays an integral role in understanding the mechanism of response to the "black sheep effect".

Social preferences trump emotions in human responses to unfair offers

People commonly reject unfair offers even if this leaves them worse off. Some explain this as a rational response based on social preferences. Others argue that emotions override self-interest in the determination of rejection behavior. We conducted an experiment in which we measured responders' biophysical reactions (EEG and EMG) to fair and unfair offers. We measured biophysical trait anger using resting-state EEG (frontal alpha-asymmetry), state anger using facial expressions, offer expectancy processing using event-related EEG (medial-frontal negativity; MFN) and self-reported emotions. We systematically varied whether rejections led proposers to lose their share (Ultimatum Game; UG) or not (Impunity Game; IG). Results favor preference-based accounts: Impunity minimizes rejection despite increasing subjectively reported anger. Unfair offers evoke frowning responses, but frowning does not predict rejection. Prosocial responders reject unfair UG offers more often after unmet fairness expectations. These results suggest that responders do not reject unfairness out of anger. Rather, people seem motivated to reject unfair offers when they violate their behavioral code but only when rejection has payoff consequences for the proposer, allowing them to reciprocate and restore equity. Thus, social preferences trump emotions when responding to unfair offers.

Distinct inter-brain synchronization patterns underlying group decision-making under uncertainty with partners in different interpersonal relationships

Humans may behave in different manners when making decisions with friends and strangers. Whether the interpersonal relationship and the characteristics of the individuals in the group affected the group decision-making under uncertainty in the real-time interaction remains unknown. Using the turn-based Balloon Analogue Risk Task (BART), the present study examined the group decision-making propensity under uncertainty with partners in different interpersonal relationships and interpersonal orientations. Corresponding inter-brain synchronization (IBS) patterns at the prefrontal cortex (PFC) were also uncovered with the fNIRS-based hyperscanning approach. Behavioral results identified that dyads in the friend group exhibited the uncertainty-averse propensity when comparing with the stranger group. The fNIRS results reported that feedback-related IBS at the left inferior frontal gyrus (l-IFG) and medial frontopolar cortex (mFPC) during different feedbacks was modulated by interpersonal relationships. The IBS at all channels in the PFC during the positive and negative feedbacks, respectively, predicted the decision-making propensity under uncertainty in the stranger and friend groups based on the support vector machine (SVM) algorithm. The moderating role of the social value orientation (SVO) was also verified in the mediation effect of the dyad closeness on the decision-making propensity under uncertainty via the IBS at the right lateral frontopolar cortex (r-FPC). These findings demonstrated disparate behavioral responses and inter-brain synchronization patterns underlying group decision-making under uncertainty with partners in different interpersonal relationships.

Role of right temporoparietal junction for counterfactual evaluation of partner's decision in ultimatum game

Humans assess the distributions of resources based on their aversion to unfairness. If a partner distributes in an unfair manner even though the partner had a less unfair distribution option, a recipient will believe that the partner should have chosen the counterfactual option. In this study, we investigated the neural basis for fairness evaluation of actual and counterfactual options in the ultimatum game. In this task, a partner chose one distribution option out of two options, and a participant accepted or rejected the option. The behavioral results showed that the acceptance rate was influenced by counterfactual evaluation (CE), among others, as defined by the difference of monetary amount between the actual and counterfactual options. The functional magnetic resonance imaging results showed that CE was associated with the right ventral angular gyrus (vAG) that provided one of convergent inputs to the supramarginal gyrus related to decision utility, which reflects gross preferences for the distribution options. Furthermore, inhibitory repetitive transcranial magnetic stimulation administered to the right vAG reduced the behavioral component associated with CE. These results suggest that our acceptance/rejection of distribution options relies on multiple processes (monetary amount, disadvantageous inequity, and CE) and that the right vAG causally contributes to CE.

Moral transgression modulates fairness considerations in the ultimatum game: Evidence from ERP and EEG data

People tend to dislike and punish unfair behaviors in social interactions, and this disposition may be moderated by the characteristics of their interaction partner. We used a modified ultimatum game (UG) to investigate players' responses to fair and unfair offers from proposers described as having performed either a moral transgression or a neutral behavior, and recorded an electroencephalogram. The participants' behavior in the UG suggests that people quickly demand more fairness from proposers who have committed moral transgressions rather than neutral behavior. Event-related potentials (ERPs) revealed a significant effect of offer type and of proposer type on P300 activity. The prestimulus α-oscillation power in the neutral behavior condition was significantly lower than that in the moral transgression condition. The post-stimulus β-event-related synchronization (β-ERS) was larger for the moral transgression condition than the neutral behavior condition in response to the least fair offers, and larger for neutral behavior than the moral transgression condition in response to the fairest offers. In summary, β-ERS was influenced by both proposer type and offer type, which revealed different neural responses to the offer from either a morally transgressive or a neutral behavior proposer.

Social distance modulates the influence of social observation on pro-environmental behavior: An event-related potential (ERP) study

Pro-environmental behavior benefits the environment but is individually costly. Therefore, understanding the neural processes of pro-environmental behavior can advance our knowledge of its implicit cost-benefit calculations and mechanisms. Previous studies have focused separately on the effects of social distance and social observation on explicit pro-environmental behavior responses, yet the underlying neurophysiological mechanism remains unknown. Using the event-related potentials (ERPs), we investigated the neural responses to the effects of social distance and social observation on pro-environmental behavior. Participants were instructed to decide between self-interest and pro-environmental choices towards different social distance targets (family members, acquaintances, or strangers) under observable and non-observable conditions. The behavioral results demonstrated that the rate of pro-environmental choices towards acquaintances and strangers was higher under the observable condition than under the non-observable condition. Nonetheless, the rate of pro-environmental choices was higher-unaffected by social observation-towards family members than towards acquaintances and strangers. The ERP results showed that the P2 and P3 amplitudes were smaller under the observable than under the non-observable condition when the potential bearers of environmental decisions were acquaintances and strangers. However, this difference did not emerge when the potential bearers of environmental decisions were family members. The ERP findings of smaller P2 and P3 amplitudes suggest that social observation may reduce the deliberate calculation of personal costs, thereby promoting individuals' pro-environmental behaviors towards acquaintances and strangers.

Interpersonal relationships modulate subjective ratings and electrophysiological responses of moral evaluations

This study explored how interpersonal relationships modulate moral evaluations in moral dilemmas. Participants rated moral acceptability in response to altruistic (prescriptive) and selfish (proscriptive) behavior conducted by allocators (i.e., a friend or stranger), toward the participants themselves or another stranger in a modified Dictator Game (Experiments 1 and 2). Event-related potential (ERP) data were recorded as participants observed the allocators' behavior (Experiment 2). Moral acceptability ratings showed that when the allocator was a friend, participants evaluated the friend's altruistic and selfish behavior toward another stranger as being less morally acceptable than when their friend showed the respective behavior toward the participants themselves. The ERP results showed that participants exhibited more negative medial frontal negativity (MFN) amplitude whether observing a friend's altruistic or selfish behavior toward a stranger (vs. participant oneself), indicating that friends' altruistic and selfish behaviors toward strangers (vs. participants) were processed as being less acceptable at the earlier and semi-automatic processing stage in brains. However, this effect did not emerge when the allocator was a stranger in subjective ratings and MFN results. In the later-occurring P3 component, no interpersonal relationship modulation occurred in moral evaluations. These findings suggest that interpersonal relationships affect moral evaluations from the second-party perspective.

Intuitive thinking impedes cooperation by decreasing cooperative expectations for pro-self but not for pro-social individuals

This study conducted two experiments to explore the effects of intuitive thinking and social value orientation (SVO) on cooperative behavior and assess the mediating effect of cooperative expectations. It manipulated intuitive thinking by increasing the participants' need for cognitive closure, classified SVO using the triple-dominance measure, measured cooperative behavior using the prisoner's dilemma game, and considered cooperative expectations based on participants' assessments of the cooperativeness of their counterparts. Both experiments showed that intuitive thinking increased and decreased the cooperation of pro-social and pro-self individuals, respectively. In pro-self individuals, cooperative expectations mediated the effect of intuitive thinking on cooperation.

The Role of Social Value Orientation in Chinese Adolescents' Moral Emotion Attribution

Previous studies have explored the role of cognitive factors and sympathy in children's development of moral emotion attribution, but the effect of personal dispositional factors on adolescents' moral emotion expectancy has been neglected. In this study, we address this issue by testing adolescents' moral emotion attribution with different social value orientation (SVO). Eight hundred and eighty Chinese adolescents were classified into proselfs, prosocials and mixed types in SVO and asked to indicate their moral emotions in four moral contexts (prosocial, antisocial, failing to act prosocially (FAP) and resisting antisocial impulse (RAI)). The findings revealed an obvious contextual effect in adolescents' moral emotion attribution and the effect depends on SVO. Prosocials evaluated more positively than proselfs and mixed types in the prosocial and RAI contexts, but proselfs evaluated more positively than prosocials and mixed types in the antisocial and FAP contexts. The findings indicate that individual differences of adolescents' moral emotion attribution have roots in their social value orientation, and suggest the role of dispositional factors in the processing of moral emotion.

The impact of social comparison and (un)fairness on upstream indirect reciprocity: Evidence from ERP

Event-related potential (ERP) technology and the dictator game paradigm are used to explore the formation mechanism of upstream indirect reciprocity behaviors. We design a within subject experiment of 3 (social comparison: upward versus parallel versus downward) × 2 (treatment: fair versus unfair) involving 49 subjects. In the first round of allocations, subjects are forced to accept a monetary amount allocated to them by another player. In the second round, subjects assume the role of allocator and divide a monetary amount between themselves and a third party. Our results show the following: 1) Having received fair treatment from someone else, individuals engaged in downward comparison are more inclined to reciprocate the fairness they had received to a third party compared to individuals in parallel and upward comparison conditions. If individuals receive unfair treatment, they tend to repeat this behavior to a third party regardless of which social comparison condition they are in; 2) Under the condition of upward comparison, individuals receiving unfair treatment exhibit greater FRN amplitude and less P300 amplitude, but in parallel and downward comparison conditions, there is no significance in FRN and P300 amplitude between individuals receiving fair and unfair treatment.

I am entitled to it! Social power and context modulate disadvantageous inequity aversion

Previous research consistently indicated that social power influences one's fairness consideration. However, it is unclear how social power and context jointly affect inequity aversion and whether these processes would be manifested in brain activities. In this study, participants were randomly assigned into either high or low power condition and then took part in a modified ultimatum game (UG) as responders in both gain and loss contexts, with their event-related potentials (ERPs) recorded. Behavioral results showed that powerful participants were more likely to reject unfair offers in both contexts compared with powerless ones. In addition, powerful participants showed a more negative feedback-related negativity (FRN) loss-win difference wave (d-FRN) upon presentation of proposed offers compared with powerless participants only in the gain context. Interestingly, in a later time window, differences of P300 responses to proposed offers were modulated by social power in both gain and loss contexts. These results suggested that powerful people were more sensitive to fairness levels and FRN may manifest fairness consideration in a gain context, but not in a loss context. Meanwhile, P300 is sensitive to fairness considerations in both gain and loss contexts.

Self-interest is intuitive during opportunity (in)equity: Evidence from multivariate pattern analysis of electroencephalography data

Fairness is a remarkable preference for human society, involving both outcome and opportunity equity. Most previous studies have explored whether fairness itself or self-interest is intuitive during outcome (in)equity. However, intuition during outcome (in)equity can be affected by both fairness level and actual payoff. Since opportunity (in)equity is only affected by the fairness level, we explored only intuition during fairness by measuring event-related potential responses to opportunity (in)equity. Participants played a social non-competitive two-person choice game with advantage opportunity inequity (AI), opportunity equity (OE), and disadvantage opportunity inequity (DI). The behavioral results suggested an opportunity inequity bias, with greater feelings of fairness and pleasantness during OE than during AI and DI. However, multivariate pattern analysis of the event-related potential (ERP) data suggested that AI, OE, and DI can be significantly distinguished from each other in relatively early windows overlapping with early positive negativity (EPN), and AI and DI can be significantly further distinguished during a relatively late window overlapping with late positive potential (LPP). Moreover, the conventional ERP analysis found that EPN amplitudes were more negative for AI than for OE and DI, as well as for OE than for DI, suggesting a pleasure bias for increased self-interest. LPP amplitudes were greater for DI than for AI and OE, suggesting enhanced sensitivity to DI. These results suggest that self-interest is intuitive during opportunity (in)equity.

The rewarding compensatory mechanism of music enhances the sense of fairness

Whether music can influence moral judgment is controversial in the aesthetics and philosophy of music. Aesthetic Autonomy pointed out that music had a morally educational function because of its lyrics or a particular context. The key to resolving the divergence is to select absolute music without lyrics or specific context as the eliciting material. In this study, 84 participants were recruited and randomly divided into three groups to complete the Ultimatum Game (UG) after listening to different stimuli: absolute music, white noise, and no sound. Behavioral results indicated that the participants’ acceptance of unfair offers was significantly lower in the music group. Also, participants in the music group have a shorter reaction time for rejecting an unfair offer than other unfair conditions. However, ERP comparison showed no significant difference in medial frontal negativity (MFN) amplitude, which reflects fairness levels, between the music group and the no sound group for either accepting or rejecting the moderately unfair offer. Brain network analyses revealed that participants in the music group showed stronger activation of rewarding circuits, including the ventral striatum, during the decision-making process of rejecting unfair offers, before the decision especially, compared to the no sound group. These results suggest that absolute music can influence fair decision-making. The reward activated by music compensates participants vicariously for the reward they receive for choosing self-interest in an unfair offer, participants no longer have to choose between self-interest and fairness norms, so the participants reject the unfair offer due to the negative emotions induced by the unfair offer.

Prosociality moderates outcome evaluation in competition tasks

The current study investigated the effect of prosociality on outcome evaluation without involving social comparison and reward processing in face-to-face competition tasks. The results showed that when faced with medium and large outcome feedback, the feedback-related negativity (FRN) amplitude induced in high-prosocial individuals was significantly more negative than that of low-prosocial individuals. In addition, the P300 amplitude induced in high-prosocial individuals was smaller than that in low-prosocial individuals in the face of large outcome feedback; hence, the prosociality score was significantly correlated with FRN amplitude. However, there was no significant difference in FRN between high-and low-prosocial individuals in the face of small outcome feedback. It was concluded that individual prosocial traits can moderate outcome evaluation.

Neural sensitivity to helping outcome predicts helping decision in real life

Prosocial helping behavior is a highly valued social practice across societies, but the willingness to help others varies among persons. In our opinion, that willingness should be associated with the sensitivity to helping outcome at the individual level - that is, increasing as a function of positive outcome sensitivity but decreasing as a function of negative outcome sensitivity. To examine this possibility, we asked participants to make helping decisions in a series of hypothetical scenarios, which provided outcome feedback (positive/negative) of those decisions. Event-related potential (ERP) response to helping outcome was recorded, such that the feedback-related negativity (FRN) and P300 were supposed to reflect the sensitivity to negative outcome and positive outcome, respectively. After the formal task, participants were asked if they would like to donate money to a charity. Consistent with our hypothesis, we found that compared to those who were not willing to donate, the participants who donated money (22 of 41 individuals) showed a smaller FRN but a larger P300. Among these participants, the amount of donation was negatively correlated with FRN response to negative outcome, but positively correlated with P300 response to positive outcome. These findings support the importance of helping outcome sensitivity to prosocial behavior.

The Relation Between Belief in a Just World and Early Processing of Deserved and Undeserved Outcomes: An ERP Study

We used event-related potentials (ERPs) to examine how quickly people in general, and certain people in particular, process deservingness-relevant information. Female university students completed individual difference measures, including individual differences in the belief in a just world (BJW), a belief that people get what they deserve. They then read stories in which an outcome was deserved, undeserved, or neither deserved nor undeserved (i.e., "neutral") while their ERPs were recorded with scalp electrodes. We found no overall differentiation between early ERP responses (< 300 ms post stimulus onset) to deserved, undeserved, and neutral outcomes. However, BJW correlated with the difference between early ERP responses to these forms of information (rs from |.44| to |.61|; ps from .018 to < .001). The early nature of our effects (e.g., 96 ms after stimulus onset) suggests individual differences in socially-relevant information processing that begins before conscious evaluation of the stimuli. Potential underlying processes include automatic attention to schema-relevant information and to unexpected (and therefore salient) information and automatic processing of belief-consistent information. Our research underscores the importance of the concept of deservingness in human information processing as well as the utility of ERP technology and robust statistical analyses in investigations of complex social stimuli.

You are excusable! Neural correlates of economic neediness on empathic concern and fairness perception

There is ample experimental evidence showing that the proposers' social role is related to individuals' fairness perception in the Ultimatum Game (UG). However, various social roles, e.g., degree of economic neediness, have different influences on fairness perception, yet it has not been well studied. In this study, we adapted the UG paradigm and recorded electroencephalography (EEG) to probe the neural signatures of whether and how the degree of neediness influences fairness perception. Behavioral results showed that responders are prone to accept unfair offers from proposers in need more than those who are not in need. At the brain level, MFN (medial frontal negativity) was more negative-going in response to unfair than fair offers for not-in-need proposers. In contrast, we found a reversed MFN difference response to unfair and fair offers for in-need proposers, showing a strongly pure altruistic phenomenon. Moreover, we found smaller P300 amplitude was induced in the proposer-in-need condition, compared with its counterpart, while a negative correlation between empathy rating and P300 amplitude in the proposer-in-need condition regardless of the offers' fairness. The current results indicate that the degree of neediness might reduce fairness perception by promoting the empathic concern toward the in-need proposers rather than decreasing the empathic concern for the not-in-need proposers.

Effects of Transcranial Direct Current Stimulation Over the Right Dorsolateral Prefrontal Cortex on Fairness-Related Decision-Making

Neuroimaging studies suggest that the right dorsolateral prefrontal cortex (rDLPFC) is an important brain area involved in fairness-related decision-making. In the present study, we used transcranial direct current stimulation (tDCS) over the rDLPFC to investigate the effects of changed cortical excitability on fairness norm enforcement in social decision-making. Participants received anodal, cathodal, or sham stimulation before performing a modified ultimatum game (UG) task, in which participants were asked to accept or reject the proposer's offer and self-rate the intensity of their anger at offers on a 7-point scale. The results showed that the rejection rate of unfair offers and anger level were higher in the anodal compared to the sham and cathodal groups, and that the level of anger at unfair offers can predict the rejection rate. Furthermore, the fairness effect of RTs was more prominent in the anodal group than in the sham and cathodal groups. Our findings validate the causal role of the rDLPFC in fairness-related decision-making through tDCS, suggesting that strengthening the rDLPFC increases individuals' reciprocal fairness in social decision-making, both in subjective rating and behaviors.

The choice levels modulate outcome processing during outcome independent of behavior selection: Evidence from event-related potentials

Having a choice is a basic demand to influence human behavior. However, how various choice levels modulate outcome processing when the outcome is independent of the choices remains unclear. In this event-related potential (ERP) study, thirty-seven participants were instructed to perform a one-person choice task in which they were required to choose one card from 1 (no-choice level), 2 (medium-choice level), and 8 cards (high-choice level) to win a reward, with a 50% chance. Behavioral results indicated that pleasure and perceived control rating scores were linearly promoted with increased choice levels. ERP results revealed that having choices (medium- and high-choice level) elicited greater original-RewP and PCA-RewP amplitudes than having no choice (no-choice level), suggesting the amplification of the reward prediction error by quickly detecting whether there is a choice or not. Moreover, ERP results revealed that the original-P300 amplitudes were linearly enhanced with increased choice levels, suggesting the increased attentional allocation based on the motivational and emotional significance, due to advanced processing of the value of choice levels. Therefore, these results suggest that choice levels can modulate outcome processing, even when the outcome is independent of the choices, and provide further evidence to support the intrinsic value of having choices.