Әділдікке ұмтылыс және теңсіздікке қарсылық

Preference for fairness and resistance to incidental inequalities
Inequity aversion (IA) is the preference for fairness and resistance to incidental inequalities. The social sciences that study inequity aversion include sociology, economics, psychology, anthropology, and ethology. Researches on inequity aversion aim to explain behaviors that are not purely driven by self interests but fairness considerations. In some literature, the terminology inequality aversion was used in the places of inequity aversion. The discourses in social studies argue that "inequality" pertains to the gap between the distribution of resources, while "inequity" pertains to the fundamental and institutional unfairness. Therefore, the choice between using inequity or inequality aversion may depend on the specific context.

Inequity aversion research on humans mostly occurs in the discipline of economics though it is also studied in sociology. Research on inequity aversion began in 1978 when studies suggested that humans are sensitive to inequities in favor of as well as those against them, and that some people attempt overcompensation when they feel "guilty" or unhappy to have received an undeserved reward. A more recent definition of inequity aversion (resistance to inequitable outcomes) was developed in 1999 by Fehr and Schmidt. James H. Fowler and his colleagues also argue that inequity aversion is essential for cooperation in multilateral settings. In particular, they show that subjects in random income games (closely related to public goods games) are willing to spend their own money to reduce the income of wealthier group members and increase the income of poorer group members even when there is no cooperation at stake. Thus, individuals who free ride on the contributions of fellow group members are likely to be punished because they earn more, creating a decentralized incentive for the maintenance of cooperation.

Surveys of employee opinions within firms have shown modern labor economists that inequity aversion is very important to them. Employees compare not only relative salaries but also relative performance against that of co workers. Where these comparisons lead to guilt or envy, inequity aversion may lower employee morale. According to Bewley (1999), the main reason that managers create formal pay structures is so that the inter employee comparison is seen to be "fair", which they considered "key" for morale and job performance. It is natural to think of inequity aversion leading to greater solidarity within the labor pool, to the benefit of the average employee. However, a 2008 paper by Pedro Rey Biel shows that this assumption can be subverted, and that an employer can use inequity aversion to get higher performance for less pay than would be possible otherwise. This is done by moving away from formal pay structures and using off equilibrium bonus payments as incentives for extra performance. He shows that the optimal contract for inequity aversion employees is less generous at the optimal production level than contracts for "standard agents" (who don't have inequity aversion) in an otherwise identical two employee model.

Fehr and Schmidt's model may partially explain the widespread opposition to economic inequality in democracies, but a distinction should be drawn between inequity aversion's "guilt" and egalitarianism's "compassion", which does not necessarily imply injustice. Inequity aversion should not be confused with the arguments against the consequences of inequality. For example, the pro publicly funded health care slogan "Hospitals for the poor become poor hospitals" directly objects to a predicted decline in medical care, not the health care apartheid that is supposed to cause it. The argument that average medical outcomes improve with reduction in healthcare inequality (at the same total spending) is separate from the case for public healthcare on the grounds of inequity aversion.