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 ...

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, ...

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 ...