NCJ Number
233840
Journal
Polygraph Volume: 39 Issue: 4 Dated: 2010 Pages: 233-250
Date Published
2010
Length
18 pages
Annotation
The purpose of this research was to investigate the relationship between accuracy of a detection of deception task and the stimulus mode of the question presentation. That is, will the presentation of questions on a computer screen change the accuracy rate when compared to exams conducted, more traditionally, in a verbal mode? Eighty subjects were assigned to either a guilty or innocent condition. Guilty subjects were shown a video of a mock crime scenario, while innocent subjects viewed a clip from a training video. Half of the innocent and half of the guilty groups were given the exams aurally using a tape recorder, and the other half shown the questions on a computer terminal. Subjects were then given a guilty knowledge test (GKT) by the experimenter using a Coulbourn polygraph.
Abstract
While the polygraph exam was being administered, a second experimenter sat across from the subject. This second experimenter was responsible for programming the subject, while the experimenter running the exam was blind to the subject's guilt/innocent status. During the exam, the subject was required to respond to the experimenter with "no" to every item. The charts were scored by the following: (1) the original examiner; (2) a blind evaluator; and (3) using a scoring system introduced by Lykken. Overall accuracy of the decisions of the original examiner was 78 percent, 74 percent for the blind examiner, and 76 percent for the Lykken system. Accuracy rates for subjects in the visual condition were 83 percent for the original examiner, 78 percent for the blind evaluator, and 70 percent for the Lykken system. The decisions for the aural condition were 73 percent accurate for the original examiner, 70 percent accurate for the blind evaluator, and 83 percent accurate for Lykken scoring system. There was no significant association between an accurate decision and the stimulus mode condition for the original examiner, the blind evaluator or the Lykken scoring decision. (X2 equals .6091; p less than .4351 and X2 equals 2.0378; less than .1534; X2 equals 1.065, p less than .3020). There was no significant association between the type of error and the stimulus mode for the original examiner (Fisher's exact p less than .14) or the decision rendered by the Lykken system (Fisher's exact p less than .25) whereas the type of error was associated with stimulus mode for the blind examiner (Fisher's exact p less than .0075). This may be due to an artifact associated with the use of the experimenter as a confronter during the exam. (Published Abstract) Tables, figures, references, and appendix