Emotion Based Moral Judgment: Differential Effects of Disgust and Anger

From the perspective of evolutionary psychology, emotions are adaptations to the recurring specific problems in the ancestral environment. Disgust is pertinent to cues connoting infectious diseases. Being an integral part of the behavioral immune system, the emotion of disgust is elicited by pathogen-connoting cues in the immediate environment. This emotion functions to minimize the contact with pathogens. In contrast, the origin of anger is irrelevant to diseases. The emotion of anger is relevant to deterring harm from others and minimizing exploitation in social exchange. In social interactions, people who are equipped with anger can reduce potential harm and unfairness from others than those who are not. Emotion is neglected in the traditional moral psychology, but more and more theoretical and empirical studies emphasize the important role played by emotion in morality. The social intuitionist model maintains that intuition based on emotion is the primary factor determining moral judgment, whereas reflection and reasoning act as a defending lawyer who only seeks supportive evidence for the conclusion drawn by the intuition. In addition, there are multiple moral domains rather than only one. These extended moral domains include fairness, harm, purity, authority, and loyalty. Empirical studies reveal that moral judgment involves in brain regions relevant to emotions, is predicted by emotions rather than by reasoning, and does not function well in sociopaths whose emotion-related brain regions are impaired. To conclude emotions involve in moral judgment, but the underlying mechanism is not well understood.;Evolutionary psychology proposes that emotions drive adaptive behaviors, and regulate many physiology and psychology parameters so as to resolve specific recurring problems in the ancestral environment. Moral psychology stresses the importance of emotions in moral judgment. In the present research, by combining these two approaches, I propose that specific emotions will drive adaptive behaviors in order to resolve the relevant context-specific problems. In specific moral domains, violations that may increase the risk of being harmed by specific threats, whether disease contagion or social exploitation, would be condemned more when the domain-relevant emotions are made salient. The emotion of disgust is relevant to pathogen threat, and drives withdrawal behavior to minimize contact with disease cues. Moral judgment derived from disgust should be related to hygienic violations that increase the risk of disease infection. In contrast, anger that is relevant to unfair social exchange drives aggression to deter social harm and exploitation by others. Thus, moral judgment derived from anger would condemn and criticize social violations specifically.;Within this evolutionary framework, I conducted three studies to explore the differential effects of disgust and anger on moral judgment. Specifically, these studies explicitly addressed the hypothesis that disgust would increase moral condemnation of hygiene violations, whereas anger would increase moral criticism of fairness violations. These differential effects were predicted to emerge when violations were related to the self. In Study 1, the two emotions were elicited by watching film clips. In Study 2, they were elicited by writing personal experiences. In Study 3, disgust and anger were elicited and measured by reading relevant behavioral transgressions. Generally, the hypothesis was supported. As predicted, disgust elicited harsher moral judgment toward hygiene violations but not fairness violations. This effect emerged mainly when hygiene violations concerned the self. In contrast, anger predicted moral criticism of fairness violations. These results show that, different from some of the existing literature, disgust specifically influences moral judgment of hygiene violations but not omnibus moral violations. These findings help to clarify the existing literature some of which erroneously equates moral and physical disgust. Consistent with the function of disgust which is to avoid diseases, the emotion is only associated with hygiene-related but not other moral violations. Another important finding about disgust is that it influences hygiene violations only when the violations concern the self. The findings also show that the relationship between anger and fairness moral judgment. This and other implications are discussed in detail.