“That’s correct. A polygraph works by measuring subtle physiological changes that typically occur during stress. Most normal people feel stress when lying. Sociopaths don’t. Pathological liars don’t. They sail right through polygraphs.”
And some people get stressed by being put on a polygraph, even though they are telling the truth.
It’s an old technology.. those that still wield it know the sociopaths that ‘sailed right thru’ and went on to be convicted or somehow never heard from again.
You could say it’s highest best use is identifying the *truth tellers*.