Polygraph Pioneer: Mechanizing the Truth

In the 1920s and 30s, criminal interrogations were brutal, imprecise, and frequently yielded false confessions. Enter Leonarde Keeler, an eccentric, obsessive criminologist who believed that the human body was incapable of lying, even if the mouth was. His invention, the modern polygraph machine, promised to eradicate deception forever by mechanically measuring blood pressure, sweat, and respirati...