Psychophysiological differentiation of deception: the effects of electrodermal lability and mode of responding on skin conductance and heart rate.

The differentiation-of-deception paradigm enables the examination of deception as a psychophysiological process by varying, within subjects, two conditions which differ only with respect to honesty and deception. The present experiment assessed the effects of two group factors - electrodermal lability and mode of responding - on the deception phenomenon in a situation with low emotional involvement and mental load. Skin conductance responses, phasic heart rate, self-rated relaxation, calmness, and concentration were the dependent variables. Twenty questions referring to general knowledge were presented on a monitor. The 88 male participants answered half of the questions deceptively and the other half honestly, depending on which of two signals appeared on the screen. Half of the subjects answered verbally and the others by pressing keys. For electrodermal lability and mode of responding, significant main effects on skin conductance and heart rate were obtained. The expected main effect of truthfulness emerged in all variables, without being affected by the group factors. These findings, therefore, extend the generality and robustness of the differentiation-of-deception phenomenon.