# Why is lie detector technology not considered viable in a USA court of law?

**URL:** <https://boards.straightdope.com/t/why-is-lie-detector-technology-not-considered-viable-in-a-usa-court-of-law/968764>\
**Category:** Factual Questions\
**Created:** [July 29, 2022, 8:11am UTC](https://boards.straightdope.com/t/why-is-lie-detector-technology-not-considered-viable-in-a-usa-court-of-law/968764 "2022-07-29T08:11:34Z")\
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**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\
**Post date:** [July 29, 2022, 1:05pm UTC](https://boards.straightdope.com/t/why-is-lie-detector-technology-not-considered-viable-in-a-usa-court-of-law/968764/21 "2022-07-29T13:05:22Z")

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On this last point, I read in a cop’s memoir (don’t remember which) that they used to get good results by having the suspect sit next to the office copy machine with a metal pasta strainer on his head. They’d have a sheet of paper on the glass with the lid closed, and every time they thought the suspect was jerking them around, they pressed the copy button and a fresh sheet would come out with the big word LIE on it.

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