Are Polygraph Tests Admissible as Evidence in Utah

While movies and TV crime dramas may depict the lie detector test as the ultimate way to catch a criminal, polygraph evidence is almost exclusively inadmissible in Utah legal proceedings. Utah law does not currently allow polygraph evidence to be introduced to prove or disprove a criminal defendant’s innocence. Utah courts have found that polygraph test results are unreliable, and certain people can pass the test while lying, while others fail the test when they are telling the truth.

If you or a loved one was charged with a crime and have questions about whether a lie detector test can be used as evidence, the Utah criminal defense attorneys at Douglas D. Terry & Associates can help. With over four decades of criminal defense experience, our law firm has defended people under investigation or accused of crimes throughout Utah. When the stakes are high, you need a skilled and experienced criminal defense lawyer with a reputation for obtaining superior results.

What Is a Lie Detector Test and How Does It Work?

A polygraph test, commonly known as a “lie detector” test, is a machine that records a person’s body signals and translates that information into a graph. The polygraph uses up to six sensors to measure variations in a person’s breathing, pulse, blood pressure, perspiration, and repeated body movements. It allegedly uses that information to draw conclusions about whether the person is lying.

Before beginning the test, the examiner will ask the subject a series of questions to establish the suspect’s “baseline” reactions and signals. Once the preliminary questions are completed, the person administering the test will ask “control questions.” These questions are designed to cause physiological reactions to understand how the subject responds to stressful questions. Examples of control questions include “Have you ever told a lie to get out of trouble? Have you ever taken something that did not belong to you, even as a child? Or, have you ever done something you were ashamed to admit?” Finally, the examiner will ask the genuine questions and record the suspect’s responses.

While the polygraph is considered to be between 60% and 90% accurate, it is not considered “generally accepted” as scientifically reliable under the Daubert-Frye legal standard for admissibility of scientific evidence. As a result, Utah courts do not allow polygraph evidence to be introduced to prove or disprove a criminal defendant’s innocence, and the Utah legislature has barred the use of polygraph test evidence in criminal proceedings.

Why Are Polygraph Test Results Inadmissible in Court?

Under Utah law, the results of a polygraph examination, the opinion of the polygraph examiner, and any reference to an offer to take, failure to take, or taking of a polygraph examination are not admissible in court.

In the 1980s and 1990s, Utah courts evaluated the use of polygraph evidence and concluded that polygraph results were not admissible. Courts found that a suspect’s reactions to the questions asked during a polygraph test are not necessarily reactions to lying. They could be a response to the stress of questioning, of being accused of a crime, or even something so mundane as the temperature of the room. Because every person reacts differently to stressful situations, it is difficult to prove that the stress reaction measured in a polygraph test is in response to the examiner’s questions and not some other factor.

Because there was no adequate scientific basis to determine whether a suspect was lying and there was division within the scientific community regarding the reliability of polygraph test results, Utah courts decided the test results could not be used as evidence. The prohibition on the use of polygraph evidence in courts was later codified in the Utah Rules of Evidence.

Can a Lie Detector Test Ever Be Used as Evidence?

Theoretically, if both the prosecution and defense attorneys were to stipulate the admissibility of polygraph test results, the results could be admissible. However, it is unlikely that a prosecutor would stipulate to lie detector test results that were helpful to the defendant.

Hypothetically, if both sides agreed, before the test was administered, to be bound by the results of the test and that the suspect was not “gaming the test,” the results of a lie detector could be used as evidence. Before submitting to the test, a suspect would need to receive the Miranda warnings and waive their right to remain silent.

In our opinion, if a criminal defendant were to agree to be bound by the results of a lie detector test, it should only be with prior written agreement from the prosecutor that the case would be dismissed if the defendant passed the test. Alternatively, a defendant could submit to a defense polygraph test. If the results were favorable, defense counsel could use the test results in support of a Motion to Dismiss.

Contact Douglas D. Terry & Associates Today

Douglas D. Terry & Associates is one of Utah’s preeminent criminal defense law firms and has represented people accused of crimes in Utah for over 40 years. Contact us today to schedule a free and confidential consultation to discuss your situation and how we can help. Call (435) 628-4411, send a message to email@SouthernUtahDefense.com, or complete our online form.