A lie detector, also known as a polygraph, is a machine that measures and records several physiological indicators such as blood pressure, pulse, respiration, and skin conductivity. The theory behind lie detection is that when a person lies, they will experience a physiological response that can be measured by the machine.
The polygraph was first developed in 1921 by John Augustus Larson, a medical student at the University of California, Berkeley. Larson’s original design was based on the premise that increased autonomic activity would be exhibited when a person was lying. The machine has undergone many changes since its inception and is now considered to be one of the most reliable tools for detecting deception read on @ https://techbullion.com/what-is-a-lie-detector-and-how-does-it-work/