The truth about lie detectors
You’ve seen polygraph tests a thousand times on crime dramas and daytime TV: a stubborn suspect gets hooked to the machine and their darkest secrets come spilling out, etched forever onto a roll of paper. Its results are often presented as fact, as black and white, but the truth about the lie detector is much more complex.
The machine was invented in Berkeley, California in the early 1920s by a rookie police officer called John
