The role of guessing and verbal response type in psychophysiological detection of concealed information

I used a card test to study the effect of guessing on psychophysiological responsivity. Results indicated that subjects who were aware of the card they chose were more responsive to the relevant card than subjects without knowledge of the card they were asked to guess. Psychophysiological responsivity to the guessed cards was greater than to the neutral cards and to chance expectancy. In a verbal response type effect, the combination of the verbal response (yes or no) and the act of lying (no) increased differential responsivity compared with silence. I found no interaction effect between the knowledge of concealed information and the type of verbal response.