[Oztrich Boy]

and people that are just flat out nervous and scared of the machine will be recorded as lying when they're telling the truth.

And that's the danger in using them for employment screening. Honest people who get distressed at the thought of lying can fail and be rejected, while sociopaths breeze through the test.

[AnAmericanMother]

There's a reason that lie detector results aren't admissible in evidence in most courts.

One of my favorite cases -- a number of years ago a couple of enterprising cops created a "lie detector" machine out of a colander, a bunch of wire, a battery, a buzzer, and a doorbell button. They set the colander on the suspect's head, asked him questions, and every so often one of them would push the doorbell button with his foot and the buzzer would go BZZZZZZZT! and the cops would yell, "YOU'RE LYING!" The guy confessed -- but the appellate court threw out the confession. I always thought trickery was AOK . . . but I guess that one just went too far.