The relationship between cerebral asymmetry and measures of psychopathy in a non-clinical sample is moderated by both empathic challenge and biological sex.

This study investigated the relationship between psychopathy, as assessed by the Levenson Self-Report Psychopathy (LSRP) scale, and cerebral laterality. EEG recordings from frontal cortex (L3 and L4) were taken during both resting conditions and while viewing a video of an emergency field amputation, used as an empathic challenge. The ratio of alpha power from the two recording site was taken as an index of relative activity in the two hemispheres. Eighty three students from the University subject pool were recruited as participants. Male participants had a significantly higher mean LSRP score than did female participants. While LSRP scores were unrelated to cerebral laterality under resting conditions, there was both a significant linear and quadratic negative relationship between LSRP scores and relative left-hemisphere alpha activity. As alpha activity has been reported to be inversely related to brain or mental activity, a negative relationship can be inferred between LSRP scores and right hemisphere neural activity. The female participants had a much stronger quadratic relationship than did the combined sample, while the male sample showed only weak, non-significant relationships. Our data suggest that the relationship between psychopathy and cerebral laterality may be sexually dimorphic.