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Polygraph - Still Lie Detecting After All These Years? Part 1

NCJ Number
82830
Journal
Social Action and the Law Volume: 7 Issue: 5/6 Dated: (1981) Pages: 86-89
Author(s)
S Sandowsky
Date Published
1981
Length
4 pages
Annotation
Various techniques for using the polygraph are described, and the pros and cons of each technique are discussed.
Abstract
One technique interposes questions about the crime with neutral or irrelevant questions under the assumption that the respondent will react more stronly to the questions related to the crime if he/she is lying. This is called the relevant-irrelevant test. It might be expected, however, that a subject will react more strongly to the relevant questions even if he/she is telling the truth, because the suject will appreciate that these questions are crucial to the outcome of the test. This form of questioning is thus in general disrepute. Another technique, known as the peak of tension or guily knowledge test, gives respondents a multiple-choice test. The correct answer, which reveals guily knowledge, is embedded among incorrect choices. The assumption is that the guilty party will react physiologically to the relevant answer and not to the others. The innocent subject will react equally to all. While this test appears to be highly reliable, it requires time and creativity to design and time to administer, so it is used infrequently. In another format, called the truth control test, the examiner asks questions about two crimes, one of which is fictitious. The respondent is led to believe that he/she has been identified as having perpetrated another crime in addition to the one for which he/she is a prime suspect. The assumption is that the answers about the fictitious crime will be true, and these will be compared to reactions associated with answers about the real crime. While this test appears to be reliable, the ethics involved are questionable. Another form of this test is the lie control test. Here, the subject is asked to reveal the truth about any former indiscretions of crimes, answers which are expected to produce evasions, and these responses are compared to questions about the crime. Innocent persons are expected to show less reaction to these questions than those about previous indiscretions. These assumptions are questionable, so this test is controversial, even though it is used often. This discussion will continue in the next issue. Five references are listed.

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