Disgust, but not anger provocation, enhances levator labii superioris activity during exposure to moral transgressions

Physical disgust is elicited by, and amplifies responses to, moral transgressions, suggesting that moral disgust may be a biologically expanded form of physical disgust. However, there is limited research comparing the effects of physical disgust to that of other emotions like anger, making it difficult to determine if the link between disgust and morality is unique. The current research evaluated the specificity of the relationship between disgust and morality by comparing links with anger, using state, physiological and trait measures of emotionality. Participants (N = 90) were randomly allocated to have disgust, anger or no emotion induced. Responses to images depicting moral, negative non-moral, and neutral themes were then recorded using facial electromyography. Inducing disgust, but not anger, increased psychophysiological responses to moral themes. Trait disgust, but not trait anger, correlated with levator labii responses to moral themes. These findings provide strong evidence of a unique link between physical disgust and morality.