If you have been accused of committing a crime, such as something as serious as a sexual assault, or of doing something wrong, such as using drugs or having an affair, a common question a person in that situation asks himself or herself is should I take a lie detector test? A lie detector, also known as a polygraph, is often depicted in popular culture as instrumental in criminal cases or custody situations. But is that depiction accurate? Should a person accused of a serious crime take a lie detector test? If so, is a lie detector test accurate? A quick google search will reveal that there are even websites out there on how to pass a polygraph and how your preparation can affect the lie detector test accuracy. However, the more relevant inquiry is is a polygraph admissible in court?
In short, the answer is no, even if you “pass” a lie detector test, the result is not admissible in court in Massachusetts. The Supreme Judicial Court, which is the highest court in Massachusetts, held that “polygraphic evidence, with or without pretest stipulation, is inadmissible in criminal trials in this Commonwealth either for substantive purposes or for corroboration or impeachment of testimony.” Commonwealth v. Mendes, 406 Mass. 201, 212, 547 N.E.2d 35, 41 (1989). That means no matter the result of the polygraph, it cannot be introduced to show that a witness or defendant is lying or telling the truth in a criminal trial. Massachusetts is not alone – most states in the country do not allow polygraph results to be introduced in criminal trials. This is because its validity is not generally accepted in the scientific testimony.
So if a polygraph is not admissible in court, then why do people still take a lie detector test? There are a number of reasons, such as the following:
1. Regardless of the lie detector test’s accuracy and admissibility in court, family members may rely upon the results in determining whether to believe a loved one’s denial of an allegation.
2. Sometimes, providing a favorable polygraph result to a District Attorney’s Office can be instrumental in determining whether a sexual assault investigation that is not supported by tangible evidence proceeds to criminal charges.
3. A polygraph is a relatively inexpensive way of determining whether an individual’s accusation is credible.
If you are facing an accusation and thinking about whether to take a polygraph, you should speak to a lawyer beforehand so that you can discuss whether it makes sense in your particular case. For some, it is a waste of time and money. For others, it might be a worthwhile strategic decision, especially since it will only be utilized if it supports your position. Regardless, you should not share the fact that you are considering taking a lie detector with anyone but your lawyer. This is because if others know you are taking a polygraph and you do not consequently share that the result is beneficial to your cause, then it might be presumed that you received a negative result, which while still inadmissible, will not be looked upon favorably.