In the movies they make it all look so easy, an innocent man answers a handful of simple questions, all while hooked up to a polygraph machine. The polygraph test, administered by an expert, can confirm our hero is telling the truth about his innocence and is set free.

If only life were like the movies.
What is a polygraph test?
The truth is, no matter how reliable you’ve come to believe a polygraph test is, what it measures is NOT whether or not you’re telling the truth or a lie but rather, whether or not the question (and the answer you give) causes you any distress or excitement. It does this by recording physiological indicators of stress like blood pressure, perspiration, and elevated heart rate.
But false negatives and positives happen all the time. In fact, the National Academy of Sciences found polygraph tests create a high number of false positive results.
This is because we all respond differently to stressors and there is no doubt that taking a lie detector test could give anyone pause. A good case of nerves can set your lie detector off. On the flip side, someone who can keep his or her physiology in check under pressure may just be able to sidestep getting caught in a lie.
That’s why the efficacy of polygraphs has been hotly debated since they were first invented in the early 1920s. It’s also why no state in the union can force you to take a polygraph test upon arrest.
You can, however, volunteer to take one and while polygraph may be widely inadmissible in court, it doesn’t mean the information gathered in questioning, often done by seasoned interrogators, cannot be used against you as a tool to fuel further investigation or to apply pressure in a legal negotiation. Here in Minnesota, the results of a polygraph test, as well as any information regarding whether or not a defendant took or refused a test is not admissible in both criminal and civil trials. (State v. Opsahl, 513 N.W.2d 249 (Minn. 1994).

But in some cases, a refusal to take a voluntary polygraph could potentially shore up law enforcement’s suspicions that you are, indeed, guilty – even if you’re not. This is why, if you’re accused of committing a crime, it’s important to have an experienced attorney guiding you through the process.
Minnesota Criminal Defense Attorney
If you are being pressured or considering volunteering to take a polygraph test as part of a criminal investigation, the you are in need of an experienced criminal defense attorney, please call our office immediately for a FREE consultation. With so much at stake, you cannot afford to hire anyone but the very best for your criminal defense case. Our Minnesota criminal defense attorneys are here to advocate for your interest during these most critical, life-changing matters. We offer 24 hour availability seven-days-a-week and charge you nothing for your first consultation, whether at our office or in jail.