Improving the Detection of Physical Countermeasures With Chair Sensors

• NCJ Number: 225356
• Journal: Polygraph Volume: 37 Issue: 2 Dated: 2008 Pages: 136-148
• Author(s): Jack Ogilvie; Donnie W. Dutton
• Date Published: 2008
• Length: 13 pages
• Publication Format: Article
• Publication Type: Test/Measurement
• Language: English
• Country: United States of America

Annotation

This paper reports on a reanalysis of unpublished data collected by V. Cholan Kopparumsolan in order to examine whether specialized sensors would improve polygraph examiners’ ability to detect covert physical countermeasures used by subjects to defeat a polygraph examination.

Abstract

The study found that the addition of the countermeasure sensors significantly improved examiners’ performance in detecting physical countermeasures used by examinees. It also determined that the presence of the sensor information did not affect the scores or countermeasure ratings of examinees who had not been programmed to perform countermeasures. The detection of physical countermeasures by polygraph examiners without the aid of special sensors has proven problematic. Examiners do not perform above chance levels when relying on only the conventional polygraph channels in order to identify countermeasures. In the current study, 96 subjects were recruited from an undergraduate introductory course in criminal justice at Michigan State University in 2002. One qualified polygraph examiner conducted all the examinations. Six law enforcement polygraph examiners were recruited to evaluate the polygraph charts. All subjects were seated in a polygraph test chair that was equipped with motion sensors. The Lafayette 76875S Activity Sensors are designed to detect an examinee’s physical movements during testing. Movements at various points on the chair are represented by electronic signals viewed as a moving line on a computer screen. Subjects were randomly assigned to six treatment groups: “innocent,” “guilty control,” “guilty practice cognitive,” “guilty practice physical,” “guilty experience cognitive,” and “guilty experience physical countermeasures.” For the purpose of this study, only three groups were used: the “innocent,” the “guilty control,” and a single combined group composed of the “guilty practice physical” and “guilty experience physical” groups. Subjects in the countermeasures group were given instructions about how to perform countermeasures designed to defeat the accuracy of the exam. 4 figures, 22 references, and appended examiner score sheet