Stuff You Should Know SYSK Selects: How Lie Detectors Work
May 11, 2019
Dive into the fascinating world of lie detectors and the science behind their operation. Discover the origins of the polygraph, including its dubious beginnings with a police officer turned inventor. Explore the subjective nature of lie detection and the technical nuances that make results contentious. Laugh along as the hosts discuss criticism of the polygraph and experiment with witty listener suggestions. Unpack myths about deception detection while navigating the ethical dilemmas of new technologies in this captivating conversation.
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Placebo Effect of Polygraphs
- Early polygraph proponents like Leonard Keeler recognized the device's placebo effect.
- People's belief in the machine's lie-detecting abilities often led to confessions.
How Polygraphs Work
- Polygraphs don't detect lies but measure physiological changes associated with fear of detection.
- This indirect approach and reliance on fear makes polygraph results subjective and controversial.
Polygraph Measurements
- Modern polygraphs measure respiratory rate, blood pressure/heart rate, and sweatiness (galvanic skin resistance).
- These measurements are recorded digitally, but the core techniques remain similar to those used a century ago.