In 1941, a few years before the publication of the Berkeley group's findings, American psychologist Hervey Cleckley had given a detailed listing of the characteristics of the psychopath, the most striking of these being the lack of remorse in the use of cruelty (Cleckley, 1988). A psychopath has a very egocentric view of the world and distorts reality in order to justify his actions. Following in Hervey Cleckley's footsteps, Robert Hare compiled in the 1980s a list of twenty indicators identifying psychopaths and measuring the intensity of their symptoms (Hare, 1991). It will become apparent below that both concepts – Hervey Cleckley's psychopathy and the Berkeley group's authoritarian personality as seen above – are combined in the psychopathic aggressor, the personality type common to all forms of extreme violence.