NPR Science Correspondent Alix Spiegel tells the story of Robert Dixon, who's in a maximum security prison in Vacaville California and is unlikely to ever get parole because of his score on the psychopath test. The test also is called "the checklist" or, more formally, the PCL-R, which stands for "Psychopathy Check List—Revised." Alix tells the story of its creation and reports that the man who created the test, Bob Hare, is concerned at how it's being used today in the criminal justice system. A version of this story aired on NPR's All Things Considered. (28 minutes)