NCJ Number
224779
Journal
Polygraphy Volume: 37 Issue: 1 Dated: 2008 Pages: 49-99
Date Published
2008
Length
51 pages
Annotation
This paper presents an overview on the history and accuracy of the Guilty Knowledge Test (GKT) and peak of tension test methods related to polygraph testing.
Abstract
There are several types of test formats that involve recording of physiological or support truth. One of the major classes of tests is those which detect concealed knowledge. Since the 1930s, polygraph examiners have used three versions of concealed knowledge tests with some frequency. They have used the peak of tension (POT) in which the solution or key item in the list is known to the examiner and perpetrators, but not to innocent subjects. In the second version of POT, called a searching peak, the examiner does not know the key word and presumes that a person involved in a crime does know, and by reactions will disclose the key. The GKT format is a test in which the key item is placed anywhere in the list, by chance, except in the first position because of the need for a buffer. The sequence of the items is unknown to the subject of the test. The name GKT suggests a use in which there will be some emotional involvement by the subject. In examining testing formats to detect concealed knowledge in more detail, this paper provides an historical overview and reliability assessment of both GKT and POT; their origin, similarities and dissimilarities, sequencing, scoring, and accuracy. Tables and references