Abstract
Background: Disgust is, at its core, an emotion that responds to cues of parasites and infection, likely to be evolved to protect human organism from the risk of disease. Interestingly, a growing body of research implicates disgust as an emotion central to human morality. The fact that disgust is associated with appraisals of moral transgressions and that this emotion influences moral judgments implies a remarkable puzzle: Why does an emotion that originally functions in the domain of infectious entities become such a good candidate to play the role of a moral arbiter? The aim of the present review is to clarify the nature of the relationship between disgust and morality. Method: First, we examine the relevant features of disgust in order to explore whether the phenomenology of disgust favors its implementation as a defensive mechanism against offensive social entities. Second, we critically review the most striking findings about the effects of disgust on moral judgments. Results: The revisited analysis of the literature strongly suggests a bidirectional causal link between disgust and moral cognition. Conclusions: We propose that the particular phenomenology of disgust (which involves a sense of offensiveness and rejection) favored the co-adaptation of this emotion to the moral domain.
