ABSTRACT
This chapter looks and the worst of the worst criminals—psychopaths and sociopaths. I differentiate these two syndromes from each other and from antisocial personality disorder. Psychopathy, as measured by Hare’s Psychopathic Checklist, is examined evolutionarily in terms of frequency-dependent selection and life-history theory, and neurobiologically in terms of the inability to properly tie the rational and emotional areas of the brain together. A variety of measures have shown this in the past, but now diffusion tensor imaging can demonstrate it unequivocally. The ratios between the metabolites of dopamine and serotonin and between testosterone and cortisol are then discussed. I then move on to sociopathy, its possible etiology, and how it is a different, but possibly more dangerous, syndrome than psychopathy.
