Terms Relating to Lie Detectors Explained – Letters U, V
United States Army Military Police School (Usamps)
- This was the US Federal polygraph instruction center from 1951 through 1986. The current school is called the National Center for Credibility Assessment (NCCA).
United States V Frye
- This is in reference to the 1923 case of James Alphonzo Fry, who was administered a deception test by Dr. William M. Marston with his discontinuous blood pressure method. Marston’s opined that Frye was truthful when he recanted a murder confession. At Frye’s trial his defense tried to have the results entered into evidence but was unsuccessful (United States v Frye 54 App D.C.46, 293 F 1013). It was the source of the term ‘The Frye Rule’ which states that “expert testimony based on a scientific technique is inadmissible unless the technique is generally accepted as reliable in the relevant scientific community.” Invoked thereafter many times in many jurisdictions to prevent polygraph admissions. Finnaly superseded by Federal Rule 702 (Daubert v Merrell Dow Pharmaceuticals, Inc – 1993) except in states not following the ‘Federal Rules of Evidence’.
Utah Probable Lie Technique (Uplt)
- The UPLT has been validated in mock crime analog studies, and has more peer- reviewed publications supporting it than any other probable-lie technique. And was developed at the University of Utah, initially influenced by the Backster Zone Comparison Test. It differs from other ZCT formats in that the relevant questions are not bracketed by comparison questions. Other unique characteristics of the UPLT are the inclusion of the photoplethysmograph, rotation of the probable-lie questions, recording of five charts when the test would be inconclusive at three charts and symmetrical cutoffs of +/-6. Recently the developers have included endorsement of the use of directed-lie questions, in place of probable-lie questions.
Utah Single Issue Test
- Traditionally used as a single issue Zone Comparison Test (Utah Single-Issue ZCT). Somewhat conservative in assigning values, it ensures that scores only get assigned to reactions clearly different in comparison. Considered more accurate than the You Phase Zone Comparison Test
Vagal Tone
- This is the measure of parasympathetic influences on the heart. It is shown as R-to-R wave intervals on an electrocardiogram and is measured by the variability of inter-beat intervals in heart rate. This function of respiratory sinus arrhythmia (RSA) fluctuates at a matching frequency with respiratory activity. The intervals begin with inhalation and shorten with exhalation. An alternative measure of stress.
Vagus Nerve
- The tenth cranial nerve which provides parasympathetic innervation to the heart and other visceral organs.
Vagus Roll (Vagus Pattern)
- See respiratory blood pressure fluctuations (RBPF).
Validity (See Accuracy)
- There are several types of validity. Construct validity is the degree to which a test measures what it professes to measure is . External validity relates to the generalizability of the research results outside of a laboratory setting.
Valsalva’s Maneuver
- Forced exhalation against a closed glottis will increase internal abdominal and thoracic pressure which results in a short-term increase in blood pressure and frequently a phasic electrodermal response. It is considered a type of physical countermeasures when used during testing because it can directly affect physiologic channels recorded with the polygraph.
Variable
- A variable is something that can be changed or varied such as elements that influence or are influenced by something.
Variance
- Average squared deviation from the mean. The variance of a sample is equal to the square of the standard deviation. Useful as a measure for tests of effects.
Variograph
- A recording variometer, a term used in meteorology, but also archaically used in Polish to denote the polygraph.
Vasoconstriction
- This is a narrowing of blood vessels, especially arterioles, which reduces blood flow to a region of the body. It takes place in some parts of the body during sympathetic nervous activity. It causes a movement of blood supplies to major muscles in preparation for the fight or flight defense. Some will also influence vasoconstriction.
Vasodilation
- This is an expansion of blood vessels, especially arterioles, which causes increased blood flow to a region of the body. Like vasoconstriction, it is regulated by the autonomic nervous system. It can also be affected by some medications.
Vasomotor
- Refers to influences of smooth muscles on internal diameters of a blood vessels.
Ventilation
- An exchange of air between the lungs and the atmosphere caused by the regular movement of the chest cavity during breathing.
Vertical Scoring System
- A method of numerical evaluation where spots are individually scored by relevant comparison question assessments. ZCT exploratory and S-K-Y tests use vertical scoring. This term is generally used to contrast ‘rank order analysis’.
Voice Stress Analysis
- A system that attempts to determine the frequency or amplitude modulation of a vocal signal in one or more frequency bandwidths, often the 8-10 Hz frequency bandwidth for a phenomenon known as microtremors. With no independent scientific assessment available it has not been validated for credibility and it therefore is not regarded as submittable evidence.
Voir Dire
- The process of questioning jurors for the purpose of excluding those with biases. It is a French term meaning “to say the truth.”
Vsa Mark
- A voice stress device. Examiner certification is not required. It does not use a standard testing format but relies on conversations or interrogations. See ‘voice stress analysis’.
