|Other Abstract||Opportunity equity is an essential component of social equity and outcome equity. Some researchers believed that opportunity equity was the better interpretation of distributive equity. However, most studies in the field of fairness decision-making have focused only on outcome equity, and the discussions of opportunity equity are insufficient. This thesis was guided by the inequity aversion theory, focused on the individual's emotional and cognitive control system, and tried to explore the psychological and neural mechanisms of fairness decision-making of opportunity equity in gain and loss contexts using the behavior, meta-analysis, event-related potentials and functional magnetic resonance imaging, to reduce the inequity and contribute to a more harmony and sustainable society. This thesis consists of two studies (6 experiments), which are described as follows:
Study 1 (Experiment 1-3): Experiment 1:In this part, a modified UG of probabilistic equity was designed to investigate the behavioral and psychological mechanisms of decision-making of probabilistic equity and outcome equity in the context of gain and loss. For the unfair probability distribution, we found the similar behavior pattern as in the outcome distribution, that is, people would choose to reject and evaluate lower for the unfair probability distribution. The results expanded inequity aversion theory by pointing out that people care about not only equality of actual payoffs but also expected payoffs. Experiment 2: In this part, the experimental paradigm was further modified to investigate the behavioral and psychological mechanisms of decision-making of opportunity equity and outcome equity in the context of gain and loss. The results showed that inequality of opportunity can induce a sense of unfairness even if the expected payoffs are equal. With the decrease of the fairness level of the opportunity distribution, the acceptance rates also decreased. At the same time, the results also demonstrated the effect of the gain-loss context in opportunity equity, i.e. inequality aversion was greater in the loss context than in the gain context. Experiment 2 further extends the inequity aversion theory by pointing out that people still care about equality of opportunity even if the number of choices does not affect the actual payoffs. Experiment 3:In this part, we used the same paradigm in Experiment 2. The difference was that after the subjects chose to accept the offer and got the feedback, they needed to evaluate the fairness of the offer again to investigate the influence of actual payoff on fairness perception of opportunity equity. Experiment 3 repeated the results of Experiment 2, that is, people would reject unfair opportunity distribution, and evaluate less fair for unfair offers. At the same level of fairness, the absence of actual payoff did not reduce fairness perceptions of opportunity equity, but better actual payoff increased fairness perceptions, suggesting that actual payoff and advantageous or same social comparisons could reduce inequity aversion and increase fairness ratings. In summary, Study 1 developed a paradigm for opportunity fairness decision-making based on the ultimatum game. The findings demonstrated that procedural equity and opportunity equity also influenced fairness perceptions and led to rejections that sacrifices self-interest to punish unfair proposers.
It also extended the inequity aversion theory by showing that people care not only about actual material payoffs, but also about expected payoffs and opportunities.
Study 2 (Experiment 4-6): Experiment 4: In this part, a meta-analysis of previous neuroimaging studies on human cooperation was conducted to examine the neural mechanisms of outcome fairness decision-making and the specific and common brain regions associated with another sub-component of cooperation, reciprocity. The results showed that the core brain networks involved in cooperative enforcement, fairness and reciprocity were the right ventral striatum (caudate-thalamus) and the right ventral medial prefrontal cortex. The neural networks of cooperative violation, unfairness, and betrayal include the insula, dorsal anterior cingulate cortex, inferior parietal lobule, and red nucleus. This part enables us to have a more comprehensive understanding of the neural basis of outcome equity and provides a good foundation for the subsequent research on the neural basis of opportunity equity. Experiment 5: We investigated the cognitive processing of decision-making of opportunity equity using ERP The results showed that unfair offer induced more positive P2 and more negative P3, suggesting that individuals showed enhanced attention on early stage and a more deliberative process for unfair opportunity distribution on late stage. Moreover, compared to the gain context, the latency of P2 was shorter while the latency of P3 was longer in the loss context, indicating a higher level of arousal and a tendency to avoid losses in the loss context. Experiment 6: In this part, participants were recruited to investigate the neural basis of decision-making of opportunity equity using fMRI. The results showed that, for the evaluation: the dorsal anterior cingulate cortex, dorsolateral prefrontal cortex, left insula, and bilateral inferior parietal lobule were activated for unfair offer; the ventral medial prefrontal cortex, posterior cingulated cortex and r rejection activated the dorsal anterior cingulate cortex, dorsolateral prefrontal cortex precuneus, bilateral insula and bilateral inferior parietal lobule; acceptance activated the caudate, posterior cingulate cortex, and bilateral posterior insula.ight inferior parietal lobule were activated for fair offer. For the decision:
Overall, this thesis explored the psychological and neural mechanisms of opportunity fairness decision-making in the gain and loss context. Study 1 explored the decision-making behavior of opportunity equity using a modified UG paradigm, and the results showed that people cared about opportunity equity as well as outcome equity. Study 2 revealed that individuals have similar neural mechanisms in the decision-making of opportunity equity as those in outcome equity, namely, reward for fair distribution, aversion to unfair distribution, and conflict between self-interest and social norms. These results expanded the inequity aversion theory by pointing out that people care about not only equity of actual payoffs but also opportunity equity. Furthermore, these results also supported the dual-system model of fairness decision-making by pointing out that there is an automatic, fast intuitive system and a controlled, slow cognitive control system. This thesis provided important enlightenment for promoting social equity.|