NCJ Number
111638
Journal
Polygraph Volume: 16 Issue: 2 Dated: (1987) Pages: 129-144
Date Published
1987
Length
16 pages
Annotation
To investigate the effects of manipulation, 60 experimental subjects were divided into 3 groups and were tested under a mock crime paradigm, and were instructed to deceive the polygraph by suppressing any indication of deception.
Abstract
For the first trial, the groups were not instructed in specific deception techniques. Prior to the second trial, the techniques presented in Table 6 were explained to all subjects. The motivation for the deception was as follows: The first group subjects received 1,000 yen if they could defeat the test, if they failed, they were punished. The second group was merely encouraged to deceive the operator. The third group was not given any motivation to deceive. GSR and heart rate were recorded. After the second trial, the first group of subjects revealed the critical items of the test to the examiner, and other two groups confessed their stolen amount of money, and in the subsequent trial GSR responses and heart rate decreased. The two groups who were motivated showed significantly greater GSR responses and more instances of increased heart rate during the test than the unmotivated group. The technique of the subject 'keeping his eyes on one point in front of himself and concentrating his mind on it' was most effective to suppress deception. This result suggests that this technique may be an effective countermeasure in field examinations, because it may suppress deceptions by criminal suspects. (Author abstract)