EVALUATION OF COUNTERMEASURES IN LIE DETECTION PROCEDURES (PSYCHOPHYSIOLOGY, FORENSIC)

The basic problem of lie detection concerns the proper identification of behavioral and physiological components associated with lying. It is apparent, though, that any technique aimed at identifying lie reactions will invite deliberate attempts at thwarting that technique. Such deliberate attempts are termed countermeasures. The present study extended and refined the early work of Kubis (1962) concerning two countermeasures aimed at creating physiological responsivity. The basic task involved a card test, in which each subject (N = 160) chose a number which the examiner tried to discover despite the subject\u27s denial. Eighty male and 80 female college students were randomly assigned to one of four conditions: (a) a control condition, (b) an own method condition, in which subjects were told to attempt to beat the machine by whatever means they wished, (c) a muscle tension condition, in which subjects were trained to tense the toe muscles to a number other than the one they had chosen, and (d) an exciting imagery condition, in which subjects were trained to bring to mind an exciting situation and attach this image to a number other than the one they had chosen. Three raters evaluated the polygraph records by attempting to pick out the number on which the subject was lying. Objective measurement of certain characteristics of the three physiological responses, electrodermal activity, blood pressure, and respiration, were also obtained. Evaluation of the response to the lie question was assessed by dividing the reaction to the lie question by the reaction to the immediately receding question. The evaluation of the effectiveness of muscle tension and exciting imagery training was clear and decisive. Both countermeasure techniques reduced accuracy of experienced raters to detect deception by directing their attention consistently to a number other than the lie (i.e., decoy). Even when alerted to the use of the decoy strategy by a subject, raters were unable to distinguish between the lie and decoy (in fact, identified one as the other). With regard to objective measurements, the use of countermeasures altered physiological responsivity to lie questions, reducing the intensity of the physiological stress reactions to lying