My psychology professor taught us all how to beat lie detectors, are they going to arrest him too? Sheesh, I'll just tell you what he told us:
1) The polygraph measures a stress response in your body. And the idea is, you are more stressed when you tell a lie.
2) But, everyone is different, so in order to tell what is stressful for you, they need to determine a baseline. So during the polygraph they will ask you some really easy questions, like what is your name.
3) For some physiological reason, if you curl your toes it produces a measurable stress response.
4) So whenever they ask an easy question, curl your toes. They won't be able to get an accurate baseline reading.
No guarantees on whether that will work. He mentioned that a good polygraph operator will be able to tell that you are messing with him, even if he can't tell which answers were lies.