Cognitive, emotional and social markers of serial murdering

Although criminal psychopathy is starting to be relatively well described, our knowledge of the characteristics and scientific markers of serial murdering is still very poor. A serial killer who murdered more than five people, KT, was administered a battery of standardized tests aimed at measuring neuropsychological impairment and social/emotional cognition deficits. KT exhibited a striking dissociation between a high level of emotional detachment and a low score on the antisocial behavior scale on the Psychopathy Checklist-Revised (PCL-R). The Minnesota Multiphasic Personality Inventory-2 showed a normal pattern with the psychotic triad at borderline level. KT had a high intelligence score and showed almost no impairment in cognitive tests sensitive to frontal lobe dysfunction (Wisconsin Card Sorting Test, Theory of Mind, Tower of London, this latter evidenced a mild impairment in planning performance). In the tests on moral, emotional and social cognition, his patterns of response differed from matched controls and from past reports on criminal psychopaths as, unlike these individuals, KT exhibited normal recognition of fear and a relatively intact knowledge of moral rules but he was impaired in the recognition of anger, embarrassment and conventional social rules. The overall picture of KT suggests that serial killing may be closer to normality than psychopathy defined according to either the DSM IV or the PCL-R, and it would be characterized by a relatively spared moral cognition and selective deficits in social and emotional cognition domains.