Terms Relating to Lie Detectors Explained – Letter A
- A Posteriori
- (L: from what comes later) That which is done after the experiment. This expression is commonly seen in research. An example of a typical a posteriori decision is post hoc statistical analyses of data that had not been anticipated by the experimenters. Opposed to a priori.
- A Priori
- (L: from what precedes) Refers to that which is done before the conduct of an experiment. An example is the number and type of subjects to be recruited for the study, or the alpha level for a PDD test result to be considered significant. Opposed to a posteriori.
- Acetylcholine (Ach)
- Neurotransmitter substance found in the motor nerves to skeletal muscle, in preganglionic autonomic endings (sympathetic and parasym- pathetic), in postganglionic parasympathetic nerves, postganglionic sympathetic nerves to eccrine sweat glands and muscle vasodilator endings, and many parts of the brain as well as in some cells in the retina. Neurons that release ACh are called cholinergic neurons.
- Acquaintance Test
- Generic term for stimulation test. The acquaintance test serves several purposes: to familiarize the examinee with the test procedures; to properly set the gains and centerings; to help detect countermeasures; and to assess the range of responsiveness of the examinee.
- Activity Monitor
- Device attached to or built into PDD testing chairs designed to record peripheral behavior activity and cooperation during the examination.
- Adrenal Exhaustion
- State in which the ability of the adrenal medulla to deliver epinephrine to the body has been depleted. This is accomplished through extensive physical activity, or from a lack of rest. Because it reduces the source of a chemical trigger to sympathetic arousal, adrenal exhaustion has been reported as a hypothetical countermeasure against the Relevant/Irrelevant Test, Peak of Tension (POT) Test, and Concealed Information Test because these formats interpret lack of phasic responses as indicative of truthfulness. There are anecdotal reports using this explanation for false negative outcomes in the older literature, though there is no empirical or theoretical foundation to support the assertion that adrenal exhaustion eliminates phasic arousal except under extraordinary circumstances, such as those experienced by the most abused prisoners of war. Direct neural connections via the autonomic nervous system perform most of the stimulation to the affected body systems, obviating the necessity of hormonal influence. As evidence, John Reid reported the successful testing of examinees who had undergone bilateral adrenalectomies.
- Adrenalin
- Trademark name for epinephrine (called adrenaline in British references), discovered and named by J. Takamine in 1901. See epinephrine.
- Adrenaline
- British term for epinephrine. See epinephrine.
- Adrenergic
- Those neurons that release the neurotransmitter norepinephrine. Also, substances that mimic norepinephrine in its physiological effects.
- Afferent Nerves
- Nerve fibers that carry impulses from the periphery toward the central nervous system. Also called sensory nerves.
- Air Force Modified General Question Test (Afmgqt)
- PDD comparison question testing format, used primarily within the U.S. Government, with flexible question orderings and numbers of relevant questions. The AFMGQT can be used in single-issue, multiple-facet, and multiple-issue PDD examinations. The AFMGQT uses relevant, probable-lie, sacrifice relevant, and irrelevant questions. Symptomatic questions are not used. See: Senter, Waller & Krapohl (2008).
- Alarm Reaction
- The first stage of general adaptation, which is triggered by the impact of the stressor and is characterized by heightened sympathetic activity.
- Algorithm
- System of standardized steps that lead to a solution. A series of decision rules. The term algorithm is frequently used in the context of automated data analysis that produces a decision or result. Algorithms have many applications; PDD algorithms analyze the physiologic data from structured examinations and make estimates of the likelihood of deception or to assess which question has elicited the greatest physiologic response. There are at least four algorithms now available for analysis of PDD data. See: Dollins, Krapohl, & Dutton (1999); Nelson, Krapohl & Handler (2008).
- All-Or-None Law
- A neuron will respond to its greatest ability or not at all. Stimuli that do not meet or exceed the threshold will not be sufficient to cause a response. Skeletal muscles, cardiac muscles and nerve tissues conform to the all-or-none law.
- Allostasis
- A central nervous system mediated, integrated brain-body response geared towards viability or survival. It occurs in regulatory systems which have no fixed set point and is comprised of both physiological and behavioral processes designed to maintain internal parameters within limits essential for life. See: Handler, Rovner & Nelson (2008).
- Alpha
- A Greek letter used to denote the probability of incorrectly rejecting a null hypothesis in statistical testing. It refers to the probability of making a Type-1 or false-positive error. If the probability of obtaining the sample result is less than alpha (often set a priori less than or equal to 0.05), the results are declared “statistically significant.”
- American Association Of Police Polygraphists (Aapp)
- Professional organization dedicated to serving the needs of criminal justice and military PDD examiners. Founded in 1977, AAPP has about 1500 members and is headquartered in Waynesville, Ohio.
- American Polygraph Association (Apa)
- Professional organization made up of PDD professionals from law enforcement, government, and the private sector. Incorporated in 1966 in Washington, D.C., the APA resulted from the merger of the several polygraph associations, including the Academy of Scientific Interrogation, the American Academy of Polygraph Sciences, the National Board of Polygraph Examiners, the International Association of Polygraph Examiners, and the International Association for Polygraph Research. It currently has about 2,400 members and is headquartered in Chattanooga, Tennessee.
- Americans With Disabilities Act (Ada)
- “An Act to establish a clear and comprehensive prohibition of discrimination on the basis of disability.” PDD is used in employee selection and loss investigation in both the public and private sector, and some provisions of the ADA limit the types of inquiries that can be included in the test coverage. Some of the lines of questioning historically taken during pre- employment screening may not be in compliance with ADA rules (e.g. historic alcohol or drug use). Provisions of the Act can be found at the Department of Labor Web site: www.dol.gov/. Examiners and agencies that perform pre-offer polygraph testing would be wise to consult with legal counsel in order to ensure their test coverage is in compliance with ADA rules.
- Anacrotic Limb
- Ascending portion of an arterial pulse wave.
- Analog Instrument
- Device that records data in a continuous form. An analog polygraph registers waveforms as continuous lines on a strip chart, whereas a digital instrument records them as discrete points. While many analog instruments are currently in use, the trend has been toward computerized instrumentation.
- Analog Study
- Experimental design that attempts to replicate real world activities under controlled circumstances, i.e. a mock crime study. Analog methodologies are frequently used in polygraph validation studies because it is possible to establish ground truth, something extremely difficult to determine independently in actual crimes. Despite this important feature, mock crime studies in polygraphy have been criticized for not being able to induce the level of emotional involvement or personal risk engendered in real criminal investigations.
- Analysis Spot
- The specific location on a PDD chart where the spot analysis concept is employed, and is generally anchored to a relevant question.
- Anecdote
- Personal narrative relating to an issue or event. Anecdotal evidence pertains to non-empirical observations, and it is sometimes used to forward an assertion for which there may be no clear evidence.
- Anova
- ANalysis Of VAriance. A family of statistical procedures designed to partition the total amount of variability in a set of scores into two parts: the parts that can and cannot be accounted for by the independent variable(s). The ANOVA is often used in psychophysiologic and PDD research.
- Anticlimax Dampening Concept
- An explanation proposed by Cleve Backster for patterns of physiological responding he observed during polygraph testing. Backster hypothesized that a person’s fears, anxieties, and apprehensions will be directed to that situation which holds the greatest threat to his or her well-being or self-preservation at that point in time. In the polygraph examination, a guilty examinee’s concern over an intense relevant question may result in a full or partial dampening of responses to other questions, such as less intense relevant questions or comparison questions. See: Backster (1963a).
- Anti-Countermeasures
- Preventative measures used by PDD examiners to block or neutralize the countermeasure efforts of examinees. For example, if the aim were to be to preclude an examinee from pressing his toes against the floor making the distinction between anti-countermeasures (proactive) and theduring testing, an anti-countermeasure might include elevating the examinee’s feet from the floor so that this strategy cannot be acted upon. Lynn Marcy is credited with counter-countermeasures (reactive).
- Aorta
- Main systemic artery from the heart. The aorta receives blood from the left ventricle through the aortic valve, normally tricuspid and having three leaflets. The upward extending portion is considered the ascending aorta, followed by a downward bend, the arch of the aorta. The portion passing through the chest is the thoracic aorta, from where the blood flows to all parts of the body.
- Apnea
- Temporary cessation of breathing. Apnea is considered the ultimate manifestation of respiratory suppression. When they are specifically associated with certain questions during a PDD examination, they are considered significant physiological reactions and strongly diagnostic of deception. True involuntary apneas almost always take place near the bottom of the exhalation cycle.
- Applied Stimulus
- Generically, an event, occurrence or change that modifies a behavior in a measurable way. In PDD, the stimuli of interest are applied in the form of test questions.
- Areopag Polarg
- Computer polygraph manufactured in Russia.
- Army Modified General Question Test (Army Mgqt)
- Test format patterned after the Reid test and developed by the U.S. military. Unlike the Zone formats, it has more relevant questions than comparison questions and does not include symptomatic questions, though some versions employ a sacrifice relevant question. The use of the Army MGQT has declined since research has shown poor validity. See: Blackwell (1998); Krapohl & Norris (2000); Podlesny & Truslow (1993).
- Arousal
- A state of excitement. Lacey proposed that three types of arousal exist 1) behavioral, 2) autonomic, and 3) cortical. Behavioral arousal can be observed in a person’s outward responses, autonomic arousal can be measured by psychophysiological changes in the peripheral nervous system, and cortical arousal can be measured as EEG desynchonization and fast waves. See: Lacey (1967).
- Arousal Theory
- One of several theories that attempt to explain PDD. It holds that stimuli have different intrinsic cognitive and/or emotional arousal potential for each subject, and discrimination between guilty and innocent subjects is achieved by assessing which type of stimuli has drawn the most responsivity which are mediated via behavioral conditioning.
- Arrhythmia
- Any variation of the heart’s normal rhythm is considered an arrhythmia. An example of a regular variation, associated with respiratory activity, is sinus arrhythmia. Examples of irregular variations include premature contractions, heart block, flutter, fibrillation and other ectopic beats. Rapid arrhythmias are termed tachycardias while slow arrhythmias are termed bradycardias.
- Arther Technique
- A probable-lie comparison question technique developed by Richard O. Arther which he taught at his training school in New York City. It was built upon the methods of the Reid school, of which he was a student. The Arther technique relies heavily on behavioral indicators to assess deception. His question series is unique in that it includes a known truth pseudo-relevant question. Arther taught thousands of students in the U.S. and abroad, and has focused on the law enforcement sector.
- Associated Research, Inc.
- A manufacturer of the Keeler polygraph, which is no longer in production.
- Attention
- The focusing or concentration of mental activity. Attention is central to the theory of salience, currently the most parsimonious explanation for the differential arousal patterns observed with the Comparison Question Technique.
- Autogenic Training
- Instruction in one form of self-hypnosis. Subjects can be taught to induce a state of profound relaxation through a series of simple exercises. Because autogenic training can help individuals modify physiological arousal, it is considered by some as a potential countermeasure against PDD. There is little data to support or refute this argument. Because autogenic training focuses on self-regulation of tonic levels of physiological activity, and conventional polygraphy relies on phasic response patterns, its usefulness in defeating modern PDD techniques is probably very limited.
- Automatic Mode
- Setting for the electrodermal activity channel, which uses some combination of filtering that may include; a low-pass filter, a high-pass filter and/or a smoothing filter. All modern polygraphs manufactured in the U.S., both analog and computerized, have this feature. While the self-centering action of the automatic mode is attractive to many PDD examiners for practical reasons, it has been criticized for filtering out diagnostic information that may not be reconstructed in the final displayed signal. Some polygraph schools recommend using the manual mode to avoid these problems. Modern instrument manufactures now often include both a manual and automatic mode to obviate this concern.
- Autonomic Nervous System (Ans)
- In vertebrates, the system of nerves that regulates all innervated tissues and organs except striated muscle fibers. The ANS is divided into the sympathetic and parasympathetic portions. The ANS performs the vegetative functions and regulates arousal levels. All conventional PDD methodologies monitor ANS activity. See sympathetic and parasympathetic nervous systems.
- Avex
- Computer polygraph manufactured in Russia.
- Axciton
- An American manufactured computer polygraph, developed and marketed by Bruce White of Houston, Texas.
- Axon
- The long central process of a neuron. A single axon extends from each cell body of the neuron to the synapse or end organ and is responsible for the transmission of the nerve impulse. In humans and other vertebrates, most peripheral axons are sheathed in a fatty layer called myelin, which acts to insulate the axon from the surrounding tissue. There are regular breaks in the myelin sheathing, called the nodes of Ranvier, that allow the electrical impulses to jump from node to node (saltatory transmission) rather than transit in the axon via the slower chemical depolarization process.
