when was the first lie detector invented
John Larson the inventor of the lie detector or polygraph first started as a medical grad at California University. This invention first was a failure by James Mackenzie in 1902, but when John Larson advanced this invention he changed what the machine studied.he test they took lasted for about 2 hours. After the test experts would examine the results to determine if the person was telling the truth about the crime. The lie detector uses different wires with a rubber pad to measure rates and pulses. They place the wires in different places on the body.