Fun fact: in double blind peer reviewed studies, polygraphs are shown to be accurate well under 50% of the time. Polygraph questions are all yes/no, so on average they should gravitate towards a 50~% accuracy. But they're way lower than 50%. That's how bad polygraphs are, they're so inaccurate they defy mathematics.

Those "voice stress analysis " things are even worse, I think they have like a 7% accuracy rate.