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261

Polygraphs—Examination Variables

The recorded differences and purported indicia of deception may be caused by numerous variables. These unassessable factors are crucial to an accurate polygraph examination. Among the proven variables are: (1) physical characteristics of the subject such as fatigue, obesity, heart disease, respiratory difficulties and abnormal blood pressure; (2) temporary or permanent mental disorders such as delusions, feeble-mindedness or insanity, which result in an inability to affirmatively participate or to be unable to differentiate between right and wrong; (3) the undetected use of alcohol or drugs; (4) distractions in the examination setting, such as extraneous noises, temperature fluctuations, or unusual objects; (5) the responses to his/her own lying; (7) a guilty party's subjective belief in his/her own innocence; (8) excessive previous interrogation; (9) prior dry run examinations leading to belief that one can beat the machine; (1) the complexity of the matters being investigated; (11) the wording of the relevant questions; (12) the extent of motivation and fear by the subject that the polygraph will detect his/her lying; and even (13) the nervousness of an innocent subject induced by fear or a guilty complex involving a different offense.