Psychopathic traits predict moral judgements in five moral domains: The mediating effect of unpleasantness

Purpose The relationship between psychopathic traits and moral judgements has evoked passionate debates among researchers. Psychopathic traits have been characterized as risk factors for immoral behaviours in both non-forensic and forensic populations; however, whether individuals with elevated psychopathic traits display atypical moral judgements has been controversial. Here, we aim to examine how psychopathic traits are related to moral judgements in five moral foundations (Care, Fairness, Loyalty, Authority, and Sanctity) and further explore how unpleasantness mediates the relationship in non-forensic and forensic samples. Methods Two hundred and twenty five college students and 219 detainees were recruited in two separate surveys. All the participants were asked to complete the moral judgement task in everyday moral scenarios, the unpleasantness ratings for the immoral behaviours and the Levenson Self-Report Psychopathy Scale (LSRP). Results Psychopathic traits predicted the binary moral distinction (moral vs. immoral category) in the Care foundation in the non-forensic sample. Moreover, psychopathic traits predicted moral acceptability ratings (continuous category) in all of the moral foundations in the non-forensic sample but only for the Care and Loyalty foundations in the forensic sample. Finally, unpleasantness fully mediated the relationship between psychopathic traits and moral judgements in both samples. Conclusions Our findings provide further evidence that individuals with elevated psychopathic traits have atypical moral judgements - emphasizing the role of unpleasantness in contributing to this phenomenon. Our study has implications for understanding and treating various deviant behaviours in psychopathic individuals.