Abstract:  Fairness is one of the basic norms in human societies. Researchers have been focusing on the perception of unfairness and the related decision-making process. The Ultimatum Game and its modified versions were typically employed to explore such issues. A large number of brain imaging studies have investigated people’s neural responses to unfairness and the neural mechanisms underlying unfairness- related decision-making and identified the involvement of several key brain regions, including anterior insula, anterior cingulate cortex, dorsolateral prefrontal cortex, medial prefrontal cortex, amygdala and temporo-parietal junction. Researches among special populations further helps to examine and clarify roles of these brain areas and characteristics of special populations’ social cognitive functions. In recent years, many studies focused on impacts of various contexts on people’s behavioral and brain responses to unfairness. Future studies might consider the usage of multi-modal data analysis methods, in combination with studies on genes and hormones, to achieve a better understanding of psychological and physiological mechanisms of unfairness and its related decision-making process.

Key words:  fairness norm, perception of unfairness, decision-making, cognitive and neural mechanisms, social context