Is it possible to fail a lie detector test when telling the truth?

Answer 1

Lie detectors are not 100% accurate, so both false positives AND false negatives are possible.

Answer 2

Yeah, it's just as possible as passing one while lying. That's why they're only considered circumstantial evidence.

Answer 3

It is.  But a good polygrapher will usually be able to determine when your nerves are effecting the test and when you are lying.  They use the machine results, and their observations, including interviews in their reports. 

Answer 4

yep, sure is, IF you are the nervous type ....................

Answer 5

It's not really a lie detector it's an emotion detector.