Abstract
The purpose of this study was to examine whether P300 amplitude of the Target and Relevant would decrease with repeated presentations of the stimulus in P300-based guilty knowledge test (GKT). After a mock crime in a situation where the examinee was instructed to steal a piece of jewelry, P300-based GKT was conducted for 4 sessions. In each session, three different kinds of stimuli were presented to the examinee 180 times in total. The P300 amplitude in response to the Target was larger than that of the Relevant. Reaction time became faster as the examinee continued to go through the consecutive sessions. However, P300 amplitude in response to the Probe and the Target did not decrease as the sessions continued. These results suggest that such a requirement for the examinee to make specific and deliberate responses might have suppressed effect of habituation on the P300.
