When President Ronald Reagan’s White House threatened thousands of government officials with polygraph exams, supposedly to protect classified data (but probably also to control press leaks), his ...

The polygraph is not a lie detector but rather an instrument that measures a person’s physiological changes to questions posed by the examiner. An elevated physiological response to a particular ...

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 ...