[Contingent negative variation (CNV) in the detection of deception task using a serial presentation of pictures]

The purpose of the experiment was to investigate the feasibility of using contingent negative variation (CNV) as an index of detection of deception. Twelve subjects were required to complete both an innocent and guilty condition in that order. In the innocent condition, a series of six pictures, two of which depicted different landscapes and four others which depicted different female faces, was presented repeatedly on a computer display. Subjects responded by pressing a button following the landscape picture (target stimulus) that was presented last in the sequence. In the guilty condition, the procedures were the same except that subjects were also required not to detect one of the female pictures in mind (critical item), which they had chosen after the completion of the innocent condition. As compared with the innocent condition, the CNV amplitudes decreased significantly immediately before the target stimulus in the guilty condition where subjects had to conceal the critical item. The implication of these data both for the psychological completion of the concealed task and the practice in the field were discussed.