Inconsistent handers show higher psychopathy than consistent handers.

Three hundred and forty-two university students completed the Short Dark Triad (SD3) and the Edinburgh Handedness Inventory (EHI). Inconsistent handers showed higher psychopathy scores than consistent handers, and no handedness differences were observed for narcissism or Machiavellianism. Participants were further subdivided by quartile into low, moderately low, moderately high, and high psychopathy groups (non-clinical). Absolute EHI scores were equally distributed among low and moderate groups, but were significantly lower for the high psychopathy group. These findings suggest that inconsistent handedness is only associated with the upper quartile of psychopathy scores. Also, males showed significantly higher psychopathy scores than females, and the ratio of male to female inconsistent handers decreased as psychopathy score increased. No gender × handedness interaction indicated that both female and male inconsistent handers have higher psychopathy scores than consistent handers. Although significant, the effects were small and 99.6% of participants were not in the range of a potential clinical diagnosis. The reader, therefore, is strongly cautioned against equating inconsistent handedness with psychopathy.