Polygraphs, also known as lie detectors, have had a lengthy and controversial history over several centuries since they have been introduced. Both embraced and reviled, the devices essentially rely on detecting physiological changes that are linked with dishonesty.
While versions date back to the ancient times through the late 19th century, John Augustus Larson invented the modern polygraphy in 1921. Named the “cardio-pneumo-psychograph,” it measured a subject’s blood pressure, respiration, and changes in pulse rates.
A controversial history
Lie detectors entered courtrooms in a 1923 criminal trial. Following that introduction, it soon gained popularity in law enforcement agencies nationwide by the 1930s and 1940s with many heralding the machines as a way to catch criminals.
However, the 1960s saw detractors decry the device with doubts, questioning the accuracy with some several tests and studies. Those in opposition began to compare it to simple chance.
Controversy aside, lie detectors have inspired others to create more evolved techniques and technology to detect lies continues its evolution, purportedly with more accuracy:
- Voice stress analysis that looks at changes in voice tone and pitch
- Brain imaging detecting small changes in various areas of the brain
- Facial recognition revealing changes in expression
While showing some promise, reliability of any type of lie detection is at best in question. Researchers continue to innovate to determine what is truth and what is a lie. Over time and with more sophisticated technology, more accurate findings can become the rule, not the exception. Until that time, countless criminal suspects may find themselves wrongfully convicted.