Psychopathy is a personality disorder that has been frequently linked to instrumental aggression (i.e., aggression for the purpose of obtaining a specified goal). Additionally, previous findings suggest that psychopathic traits are related to limited perception of distress in others, including victim distress. This low reactivity may be the underlying mechanism between psychopathic traits and increased instrumental aggression. The purpose of the study was to examine the relationship between psychopathic traits and instrumental aggression evinced in order to dominate an ostensible co-participant. This relationship was examined as a function of victim distress. Participants received feedback on an ostensible co-participants distress (i.e., high vs. low levels of distress) and then assigned pain for the co-participant to endure. Aggression was measured by intensity of pain (via several stimuli) that participants assigned. Overall, hypotheses from the study were largely supported. Participants generally assigned less pain to the ostensible co-participant endorsing high-distress. Additionally, high levels of psychopathic traits were frequently related to group assignment (i.e., participants high on psychopathic traits assigned similar pain amounts to the co-opponent despite level of distress while individuals lower on psychopathic traits assigned less pain to the distressed co-opponent). Exploratory analyses revealed these findings were moderated by sex such that men were less influenced by group assignment (when high on psychopathic traits) than their female counterparts. Findings are discussed in context of relevant theoretical models of psychopathic behavior with implications drawn for future research.
