Among the colorful, eccentric and often highly unethical characters who populate the history of the polygraph was the virtuous John Larson, who in 1920 was the only cop in America with a doctorate, ...

Add Yahoo as a preferred source to see more of our stories on Google. American inventor John Larson, right, demonstrates the operation of a polygraph at Northwestern University in Evanston, Illinois, ...

Polygraph exams are commonly called "lie-detector tests" but experts say that's not true. The FBI and other agencies are using polygraphs to find leakers. But do they work? Federal agencies have ...

A version of this story appeared in CNN’s What Matters newsletter. To get it in your inbox, sign up for free here. When President Ronald Reagan’s White House threatened thousands of government ...