Psychopathy comprises affective (eg lack of empathy, superficial charm, shallow emotions) and antisocial lifestyle features (eg criminal behaviour, impulsivity). The nature of the deficits in empathie responding remain poorly understood but recently authors have claimed that psychopaths know right from wrong but do not care.

To explore the relationship between moral judgement and psychopathic traits in a healthy population (n = 198 females and n = 103 males).

We used a number of online questionnaires to assess key features of psychopathy including primary and secondary psychopathy (Levenson's Psychopathy Scale), moral judgement (Moral Judgement Test), impulsivity (Barratt Impulsivity Scale), life history of aggression (Life History of Aggression questionnaire), and cognitive and affective empathy (Questionnaire of Cognitive and Affective Empathy) in a healthy student population. We explored relationships between moral judgement scores and the other constructs using correlational analysis and comparisons between upper and lower quartiles.

We found correlations that were consistent with current literature for example, total BIS scores correlated strongly with Secondary Psychopathy scores (r = 0.57, p < 0.01). Primary psychopathy correlated with cognitive empathy (r = 0.3, p < 0.01). However, we did not observe any significant correlations between moral judgement scores and psychopathy scores.

In this healthy control population moral judgment scores do not show a significant relationship with psychopathy scores. Low empathy and high impulsivity scores observed in individuals with high psychopathy scores may not be related to a lack of understanding of moral concepts. These findings will have to be confirmed in a clinical population.