Sex-based Difference In Fairness Norm Compliance And Its Neural Mechanism In Different Situations

In society,fairness norm is the guarantee of goods exchange.Laws that define norms may restrain people and establish social order by punishing unfair behavior.And in this situation,humans comply with acceptable behaviors of their social groups.Social norms,is formed through reinforcement by social interaction and feedback,can guide humans' economic behaviors by setting boundaries around what is socially acceptable versus less acceptable.Social norms can take a variety of forms,ranging from moral valence to laws.Therefore,behavior will be based on internalized value and enforceable rules to show different levels of fairness.People often need to make continuous decisions and adjust their behavior based on empirical feedback.Consequently,it is worth our attentions to whether we can strike a balance between punishment and internal value,and then reach the most effective normative constraints.As an important factor affecting human cognition and behavior,gender has also become a topic of concern in the field of cognitive neuroscience.The neural networks govern the social behavioral performance.Previous studies have shown that males and females could differ in their neural.We also found that they show difference in social decision-making.Moreover,there may be different cognitive mechanisms behind the same behavioral results.Therefore,it is important to understand sex differences at the cognitive and behavioral levels by investigating the differences in neural activities.In conclusion,this study uses the ultimatum game and dictator game as paradigms.And with the functional magnetic resonance imaging(fMRI)and transcranial direct current stimulation(tDCS),it explores the fairness behavior and neural activities of proposers under the different situation(voluntary vs punishment).And focus on continuous decision making,and clarify the impact of punishment on subsequent fairness decision.Finally,we investigate whether there is sex difference in neural circuits under different situation.Combining behavior data,questionnaire data and brain imaging data,we found that:(1)In non-punishment situation,individual's behaviors are more self-interested,but not absolute selfish.Compare to transfers in voluntary condition,the transfers increased when a sanctioning threat became present.Transfers slightly decreased after punishment.However,the females and males show more consistent behavior trends in different situations,the psychological mechanisms behind them are different.(2)Neural mechanisms in fair decision-making generally involve psychological networks(anterior wedges,left cingulate gyrus),reward system(orbitofrontal cortex,striatum),emotional arousal(hippocampus,cingulate gyrus)and cognitive control(prefrontal cortex).And there are different brain activities under different situation.However,the females and males show more consistent behavior trends in different situations,they have different behaviors in brain activity.Therefore,there are sex-based neural differences in fairness compliance.(3)The rDLPFC plays an important role in fairness compliance.With the tDCS,we found that rDLPFC is involved in both voluntary and sanction-induced fairness norm compliance,it has an opposite role in the two type of compliances.Moreover,there is sex-based differences in the rDLPFC role in fairness norm compliance.From the perspective of behavioral,many social problems originate from behavioral issues,which are result of individuals' decision-making.Consequently,this study focuses on fairness norm compliance,explore how it affects people's economic decisions and its neural mechanism.Furthermore,clarifying the psychological mechanism and neural mechanism of males and females can help us guide people of different sex to make fair decisions more effectively.The study can help us understand people's fairness norm compliance,so as to explain and intervene with individuals' behaviors.Moreover,the results also help various organizations to formulate and implement policies.