Psychopaths know right from wrong but don't care

Abstract

Adult psychopaths have deficits in emotional processing and inhibitory control, engage in morally inappropriate behavior, and generally fail to distinguish moral from conventional violations. These observations, together with a dominant tradition in the discipline which sees emotional processes as causally necessary for moral judgment, have led to the conclusion that psychopaths lack an understanding of moral rights and wrongs. We test an alternative explanation: psychopaths have normal understanding of right and wrong, but abnormal regulation of morally appropriate behavior. We presented psychopaths with moral dilemmas, contrasting their judgments with age- and sex-matched (i) healthy subjects and (ii) non-psychopathic, delinquents. Subjects in each group judged cases of personal harms (i.e. requiring physical contact) as less permissible than impersonal harms, even though both types of harms led to utilitarian gains. Importantly, however, psychopaths' pattern of judgments on different dilemmas was the same as those of the other subjects. These results force a rejection of the strong hypothesis that emotional processes are causally necessary for judgments of moral dilemmas, suggesting instead that psychopaths understand the distinction between right and wrong, but do not care about such knowledge, or the consequences that ensue from their morally inappropriate behavior.

Fig. 1

The left column presents the results for subjects’ judgments of all 21 dilemmas. There were no differences between healthy controls (white bar, n = 35), non-psychopathic delinquents (gray bar, n = 23), and psychopaths (hashed bar, n = 14) for the mean proportion (+s.d.) of Yes judgments. The right column presents the results for subjects’ judgments on impersonal (top) and personal dilemmas. Again, there were no differences between groups. However, all three groups judged impersonal dilemmas as more permissible (i.e. a higher proportion of Yes judgments) than personal dilemmas.

Fig. 2

Scatterplot of subjects’ judgments (mean proportion of Yes responses) for all personal moral dilemmas, divided into self-serving (far left, first three cases) and other-serving (right, 11 cases) vignettes. Healthy controls are indicated by white circles, non-psychopathic delinquents by gray circles, and psychopaths by hashed squares.

Fig. 3

(A) Scatterplot of psychopathy factor 1 scores for offenders [psychopaths and non-psychopathic delinquents[ [N = 15*] grouped by the proportion of yes judgments for all personal moral dilemmas. (B) Scatterplot of psychopathy factor 2 scores for offenders [N = 15*] grouped by the proportion of yes judgments for the personal moral dilemmas. *: For 20 individuals, crime files documented the administration of a PCL-R interview. However, these juridical file records only described PCL-R total score without mentioning both factor scores.

Fig. 4

(A) Scatterplot of psychopathy scores (PCL-R; N = 12*) grouped by type of crime, against the proportion of yes judgments for all personal moral dilemmas. (B) Scatterplot of psychopathy scores (PCL-R; N = 12*) grouped by type of crime, against the proportion of yes judgments for the high conflict, other-serving personal moral dilemmas. *: For two individuals, crime files documented the administration of a PCL-R interview. However, these juridical file records only described these subjects as being a psychopath without mentioning the exact PCL-R score.