Fairness is at the core of human morality, and the key to maintain social cooperation and promote social development. As a member of the society, people are looking forward to the realization of fairness; and when treated unfairly, they act with a sense of inequity aversion. Fairness and inequity aversion are two sides of one coin. Inequity aversion means the urge to allocate resources equally as a distributor, and the willingness to give up self-interest to move in the direction of a more equitable division as a responder. Inequity aversion is beneficial for the establishment and maintaining of the fairness norm, which is significant for the realization of social fairness. However, previous research mainly focus on children’s inequity aversion as a proposer, or a responder, with no systematic comparison between these two characters. Previous research has also paid much attention to children’s inequity aversion to unfair outcomes, neglecting their aversion to unfair distributive procedures. Empathy for others usually promotes one’s prosocial behavior. However, little has been known about its relationship with inequity aversion. The present research would systematically investigate children’s inequity aversion in distributive outcomes and procedures in three aspects. Study 1 investigated children’s preferences toward fair distributions or procedures as proposers. Study 2 investigated children’s rejection of unfair offers or outcomes coming from unfair procedures as responders. Study 3 tried to find the relationship between empathy and inequity aversion. One hundred and sixty-two 4-8 years old children participated in this study.
Study 1 investigated children’s aversion of keeping unfair outcomes or using biased procedures, as a proposer. The results revealed difference in the development of these two aversions. Even when one’s own material interest was involved, children aged 3 to 8 prefer to allocate resources equally or by need, with little consideration of the different effort paid. When the other was in no need, children mainly distributed resources equally between themselves, avoiding advantageous or disadvantageous allocations. Other’s need decreased children’s inequity aversion, making children’s, including the youngest 3-4-year-old’s, distribution more favorable to the other. Children seldom took the different effort paid into consideration. Seven-8-year-old children, on the other hand, were more likely to satisfy the other’s need for three fruit erasers when it had paid more effort than when it labored less. When choosing distributing procedures (wheels), children developed differently in their aversion to advantageous vs. disadvantageous procedures. Three to 4-year-old children have already shown their aversion to disadvantageous procedure, choosing the fair procedure rather than the unfair one to determine the distribution of resources. When the alternative was more advantageous to the self, however, 7-8-year-old children started to show some inequity aversion.
Study 2 explored as a receptor of the distribution, children’s response toward unequal distributions or biased procedures. Children’s response to other’s equal or unequal distribution (advantageous or disadvantageous toward oneself) shew that as that is, when a distribution was more associated with the proposer’s interest, it was more likely to be rejected by 5-6 and 7-8- year-old children. Study 2 explored as a receptor of the distribution, children’s response toward unequal distributions or biased procedures. Children’s response to other’s equal or unequal distribution (advantageous or disadvantageous toward oneself) shew that as age grew, children were more ready to give up their resources to reject unequal offers, whether they were advantageous or not. At the age of 7-8, disadvantageous aversion was much stronger than advantageous aversion. T-year-old children accepted any offer proposed, regardless of its fairness. Five-6-year-old children began to reject advantageous and disadvantageous unequal distributions, with no difference between these two rejections. Seven-8-year-old children’s AI and DI both increased, with stronger DI than AI. In addition, proposer’s intention toward the material resource context could enhance children’s inequity aversion. When an unequal distribution was proposed by a second-party whose self-interest involved instead of a neutral third-party, that is, when a distribution was more associated with the proposer’s interest, it was more likely to be rejected by 5-6 and 7-8- year-old children.
Study 2 also found that as a responder, children generally tended to accept the outcomes generated through fair or unfair procedures. When the unfair procedure was chosen, however, 7-8-year-olds were more likely to reject its outcomes, whether advantageous or not, than when a fair procedure chosen. Results from study 2 generally suggested that children’s aversion toward biased procedures was much later developed than their aversion to unequal outcomes.
Study 3 investigated the relationship between children’s empathy and inequity aversion and found different measurements of empathy were associated differently with inequity aversion. Affective empathy was not related with inequity aversion. Higher cognitive empathy could be positively related with the rejection of unfair offers, but also with the acceptance of unequal offers, and the inclination to maximize self-interest, depending on the specific measurement of cognitive empathy. Perspective taking of friends’ emotions and the gaffe’s intention was positively correlated with inequity aversion. Other scores reflecting cognitive empathy, such as theory of mind, questionnaire of cognitive empathy, and understanding the belief and emotion about the gaffe, on the other hand, were positively related with the acceptation of unfair offers and selecting self-beneficial distributive procedures.
In conclusion, the present research revealed that different aspects of inequity aversion follow distinct developmental path. But most of them will get stronger with age, and be enhanced by the sociability of distribution context. Children at 3-4 were able to initiate an equal distribution of resources, and avoid self-disadvantageous procedures. As a responder, however, older children can reject other’s unequal distributions, mainly based on outcomes. At the age of 7-8, children can reject distributions based on the inequity of procedures. Considerations of other’s need would decrease children’s inequity aversion, but the difference in effort has no impact on the distribution. The development of inequity aversion is associated with inequity aversion. But as the construct of empathy is rather complex, different component and measurement might shape different relationship with inequity aversion. The current research contributed to our knowledge of children’s development of fairness, and provided theoretical evidence for promoting children’s prosocial behavior and