Response modulation deficits in psychopathy: evidence from stimulus and response processing

Abstract

The response modulation hypothesis of psychopathy states that psychopaths' inability to adapt their behavior to changing circumstances results from a reduced ability to process peripheral cues in the midst of a dominant response. However, other research suggests that psychopathy may be related to more widespread cognitive processing deficits. This study examined the relationship between psychopathic traits, stimulus and response processing, response modulation, and error monitoring using a lexical decision stop signal task. Processing of the go stimulus was measured using the P3 ERP component and processing of the stop signal was measured using the N1 and P3 components. Processing of errors was examined using the ERN. Participants high in impulsive antisociality (IA) showed no differences in P3 amplitude following the go stimulus but did show reduced ERN amplitude after lexical decision and SS errors, indicating a deficit in their ability to recognize when errors were made. They also show reduced N1 amplitude following SS indicating reduced processing of this cue. Participants' N1 amplitude significantly mediated the relationship between IA and the ERN following SS errors, and that both the N1 to the SS and the ERN following SS errors mediated the relationship between IA and SSRT. Thus, response modulation deficits in the impulsive-antisocial factor of psychopathy lead to deficits in both behavioral inhibition and error monitoring.