The effects of reward and punishment on response inhibition in non-clinical psychopathy

Response inhibition is an important control mechanism in reacting effectively to sudden changes in the environment, and a deficit in this mechanism is thought to be a main feature of various impulse control disorders, including psychopathy. This study investigated the effects of reward and punishment on the inhibitory capabilities of non-clinical participants with both high and low levels of psychopathy. Forty participants performed a stop-signal task under three conditions in a mixed factorial design: a no reward or punishment (N) condition, a low magnitude reward and punishment (L) condition, and a high magnitude reward and punishment (H) condition. Participants with low psychopathy were more inhibited during both reward and punishment conditions as compared to the no reward/punishment condition. On the other hand, participants with high psychopathy showed increased response inhibition only during the L condition. The presence of reward and/or punishment, regardless of magnitude, increases response inhibition in participants with low psychopathy, whereas high levels of reward and/or punishment do not affect response inhibition in high psychopathy participants. These results suggest that a deficit in response inhibition under incentive conditions could constitute a dimensional feature or aspect of clinical and non-clinical psychopathy.