A psychophysiological study of determinants for detection of deception.

Three studies were conducted to obtain available data on the determinants for detection of deception rates. (a) Psychophysiological measures were evaluated for effectiveness in detecting deception. A relevant-irrelevant method was used with two conditions; neutral stimulus and personal stimulus. Of the physiological variables, skin potential response, skin resistance response, finger pulse volume, and skin blood flow were significant indicators of deception. (b) Three experiments were conducted to study the psychophysiological effects of false and true feedback of skin potential response on the detection rates. It was concluded that the subjects receiving information that they were detectable were easier to detect than the subjects who believed that they were not detected and the subjects who received feedback of actual responses. (c) With the use of skin potential response channel, significant detection rates were obtained for all experiments under the condition that subjects verbally lied by means of "No" responses. On the other hand, the subjects who were motivated to deceive produced differentially augmented responses in the absence of any verbal response and also when the subjects told the truth to critical items and lied to irrelevant ones.