Polygraph:
The Lie Detector, AKA the polygraph, was invented by James Mackenzie in the 1920s. Mackenzie was a student at the University of California during the 20s. The Lie Detector became a huge deal because police started to use them as a way to find out if people were lying or not. It was most commonly used with witnesses or suspects of investigations.
This is a picture of a polygraph.
"HowStuffWorks "How Lie Detectors Work"" HowStuffWorks. N.p., n.d. Web. 21 May 2014.
"HowStuffWorks "How Lie Detectors Work"" HowStuffWorks. N.p., n.d. Web. 21 May 2014.