] As part of an extensive, in-depth interview, a trained
] examiner rates the offender on a 20-item personality
] test. The items include glibness and superficial charm,
] grandiose self-worth, pathological lying, proneness to
] boredom and emotional vacuity. The subjects earn zero
] points if the description is not applicable, two points
] if it is highly applicable, and one if it is somewhat or
] sometimes true.

] The psychologist who devised the checklist, Dr. Robert
] Hare, a professor emeritus at the University of British
] Columbia in Vancouver, said that average total scores
] varied from below five in the general population to the
] low 20's in prison populations, to a range of 30 to 40 -
] highly psychopathic - in predatory killers. In a series
] of studies, criminologists have found that people who
] score in the high range are two to four times as likely
] as other prisoners to commit another crime when released.
] More than 90 percent of the men and a few women at the
] top of Dr. Stone's hierarchy qualify as psychopaths.

] In recent years, neuroscientists have found evidence that
] psychopathy scores reflect physical differences in brain
] function. Last April, Canadian and American researchers
] reported in a brain-imaging study that psychopaths
] processed certain abstract words - grace, future, power,
] for example - differently from nonpsychopaths.

] In addition, preliminary findings from new imaging
] research have revealed apparent oddities in the way
] psychopaths mentally process certain photographs, like
] graphic depictions of accident scenes.

] No one knows how significant these differences are, or
] whether they are a result of genetic or social factors.
] Broken homes and childhood trauma are common among brutal
] killers; so is malignant narcissism, a personality type
] characterized not only by grandiosity but by fantasies of
] unlimited power and success, a deep sense of entitlement,
] and a need for excessive admiration.

] "There is a group we call lethal predators, who are
] psychopathic, sadistic, and sane, and people have said
] this is approaching a measure of evil, and with good
] reason," Dr. Hare said. "What I would say is that there
] are some people for whom evil acts - what we would
] consider evil acts - are no big deal. And I agree with
] Michael Stone that the circumstances and context are less
] important than who they are."

This is only a piece of a three page article discussing the issue of what determines if someone is evil.