A simple way to cheat the polygraph is to deliberately distort your physiological readings when telling the truth, such as by biting your tongue, or imagining an embarrassing incident in the past.
Can a lie detector test be fooled?
Many courts agree. Lie detector results are often not admissible in trials. Researchers have found that polygraph machines may detect lies in some cases. Still, they point out that the machines often make errors.
Is it easy to fail a polygraph test?
The easiest way to fail a polygraph examination is to lie, but thats not the only way. Since its invention in 1921, a constant crusade among subjects of the “lie-detector test” has been how to fib and get away with it; a more pressing question, perhaps, is what happens when you tell the truth and it dings you anyway.