Even an expert doesn't always know when he's confronted by a psychopath, as Jon Ronson, author of "The Psychopath Test" said last during his interview with Jon Stewart on "The Daily Show."

Ronson said it took him three hours to realize that a prisoner he went to visit was actually a psychopath. The tell tale sign came when the prisoner said, "If you can get people to like you, you can manipulate them to do whatever you want them to do."

Ronson also provided some very startling statistics. Stewart said that most of us assume that the psychopath is solely "the guy who as bodies buried in his backyard," but the truth is, you might even work with a psychopath. Ronson stated, "One out of every 100 people walking around are psychopaths." Twenty-five percent of the prison population is psychopaths, as well as four percent of corporate chiefs.

If you're interested in finding out whether or not you're a psychopath, you can buy Ronson's book and take the test. Stewart himself took the test and was "happy to report [he is] just neurotic."

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