Testing the left hemisphere activation hypothesis in psychopathic offenders using the Stroop task

Prior investigations of selective attention using the Stroop task have indicated individuals with high levels of psychopathic traits show reduced Stroop interference only when there is spatial separation of conflicting information. However, theories of psychopathy such as the left hemisphere activation hypothesis make specific predictions regarding the impact of rewards which have yet to be tested. Ninety-nine incarcerated male participants were assessed for psychopathy trait levels using the Psychopathy Checklist-Revised (PCL-R Hare, 1999) and completed four Stroop task variants, in which the spatial separation of conflicting information and the presence of financial reward/punishment contingencies varied. While the study failed to replicate previous findings of reduced interference on spatially separated Stroop tasks in individuals with high levels of psychopathy, the novel finding of reduced facilitation under reward conditions provides evidence corroborating the left hemisphere activation hypothesis of psychopathy.