Mental Floss

The Number of the Day: 4%

Colin Patrick

Related Fact: The most common tool used for diagnosing someone as a psychopath is the Psychopathy Checklist-Revised (PCL-R) developed by Robert D. Hare. In the episode of This American Life linked below, the show’s host and staff take their turn completing the questionnaire.

[Sources:This American Life. See previous Numbers of the Day here. ]