Electrodermal differentiation of deception: potentially confounding and influencing factors.

The demonstration of deception as a psychological process requires a comparison of physiological responding to questions answered honestly or deceptively, under conditions which differ only with respect to deception. Such electrodermal (skin conductance response (SCR) differentiation was recently reported in the Differentiation-of-Deception Paradigm. The present study had two empirical goals: (a) to assess the possible confounding role of retrieval-difficulty and novelty in producing the differentiation effect; (b) to ascertain any influencing effects of a memorial ('cumulative' mental load) and two motivational (Monetary-Incentive and Ego-Involvement) factors on the electrodermal differentiation phenomenon and on overall responding. In addition to the basic Deceptive vs. Honest manipulation of the Differentiation-of-Deception Paradigm, the present study varied, within 60 subjects, Question Type (easily retrieved Autobiographical vs. more difficult-to-retrieve Biographical). The two two-level motivational factors were varied between subjects. Finally, to assess the confounding issue, voice latency (VL), known to be sensitive to retrieval-difficulty, was measured in addition to SCR. SCRs to deceptive answers exceeded those to the honestly-answered questions, demonstrating the differentiation phenomenon. Results showed that although VL and SCR was significantly greater to Biographical than to Autobiographical questions, the differentiation effect emerged only in the SCR and not in VL, which suggests that memorial difficulty does not confound the electrodermal differentiation effect.