Can a Polygraph (Lie Detector) Test Be Used Against Me in Court?

June 22, 2021 Criminal Defense

Can a Polygraph (Lie Detector) Test Be Used Against Me in Court?

What is a Polygraph or Lie Detector Test?

Polygraph examinations have become culturally iconic tools used in movies and television whose subject matter is criminal investigations. A polygraph test uses a recording instrument that records physiological changes in the body in order to examine whether a lie is being told based on the subject’s heart rate, blood pressure, respiration, and skin conductivity.[1] The iconic image of a polygraph is the subject covered in wires, sticky pads, and a pen scratching back and forth along a lined piece of paper. However, in the modern world polygraph examinations are largely done using computerized recording systems that measure the cardiovascular activity of the subject when they respond to questions.[2] The term “lie detector” associated with polygraph tests isn’t exactly correct because this detection involves a series of inferences through an analysis of the subject’s physical response to questioning.[3]

What is not widely known is that a typical polygraph examination involves two phases: the pretest phase and the actual examination. The pretest phase is an interview during which the administrator of the test informs the subject about the nature of the test and conducts a “stimulation test” which demonstrates to the subject how the instruments measure “deception.”[4] During the examination phase, several questioning techniques can be used. The most popular is the Control Question Test (CQT) which compares responses to relevant questions, like those having to do with the criminal activity in question, with control questions, or questions that reference past misdeeds related to the activity, but not specifically about the criminal activity, like if the subject has ever betrayed someone.[5] The administrator of the exam will think the subject is telling the truth if they have a fear-based response to the control questions rather than the relevant questions because the control questions are designed to make a subject worry about their past integrity while relevant questions are regarding a crime that the subject, hopefully, did not commit.[6] If a subject has a larger physiological response to the relevant questions than to the control questions, the administrator will infer that to mean that the subject is lying.[7] If the administrator finds no physiological difference between the control and relevant questions, the administrator will infer that the results of the examination are inconclusive.[8]

Is a Polygraph Test Admissible Against Me in Court?

Polygraph evidence is generally inadmissible in Florida due to its unreliability.[9] However, these examinations do have limited areas of admissibility. First, they are admissible if both parties stipulate, or agree, to the test’s admissibility.[10] Second, they have limited admissibility if they are used as the basis to form an expert witness’s opinion alongside other actuarial assessment tools.[11] For example, in cases involving sexual violence, Florida courts have considered the admissibility of expert opinion regarding the propensity to commit acts of sexual violence through the use of risk-assessment tools, including polygraph examination results, and not one court has held that such testimony is inadmissible as a matter of law.[12] During trial court hearings regarding the involuntary commitment of someone charged with a sexually predatory crime, courts have allowed expert testimony by the psychologist detailing the results of the test subject’s polygraph examination to be admissible.[13] Case law on the issue indicates that, in the area of sexually violent crime, polygraph examinations are admissible if introduced under the larger umbrella of why and how an expert witness formed the particular opinion that they did.[14]

How Pumphrey Law Can Help

Though polygraph, or lie detector tests, are not generally admissible in court, they can be introduced in limited circumstances. As a basis for expert opinion, these results can hold great weight in front of a judge or jury. If you or a loved one has been subjected to a polygraph examination, it is imperative that you retain counsel well educated in polygraph examinations and their admissibility. Contact a Tallahassee criminal defense lawyer as soon as possible to explore your options and ensure that your test results are being used in the way that you desire. Don Pumphrey and the members of the legal team at Pumphrey Law Firm have years of experience dealing with polygraph examination results and can ensure that you or a loved one have those results used in a manner most beneficial to the case. Call a defense attorney today at (850) 681-7777 or send an online message to discuss your options during an open and free consultation with an attorney in our legal team.

This article was written by Gabi D’Esposito

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[1] The Truth About Lie Detectors, American Psychological Association (2004).

[2] Id.

[3] Id.

[4] Id.

[5] Id.

[6] Id.

[7] Id.

[8] Id.

[9] Duest v. State, 12 SO.3d 734, 736 (Fla. 2009).

[10] Brown v. State, 452 So.3d 122 (Fla. 1st Dist. App. 1984).

[11] Roeling v. State, 880 So.2d 1234, 1239 (Fla. 1st Dist. App. 2004).

[12] Id.

[13] Chukes v. State, 90 SO.3d 950, 955 (Fla. 5th Dist. App. 2012).

[14] Holder v. State, 123 So.3d 136, 137-38 (Fla. 5th Dist. App. 2013); Chukes, 90 So.3d at 955; Spivey v. State, 100 So.3d 1254, 1257 (Fla. 5th Dist. App. 2012).

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