Abstract
The topic of our research is the detection of concealed information based on ERP. We used visually concealed information test(CIT) based on P300 in the experiment. There are three kinds of stimulus in CIT. One is Probe, which is related with concealed information. The other is Irrelevant, which is not related with it but consists of same category as Probe. And the other is Target, which is for calling subject's attention to the experiment. In CIT, the stimulus are presented and the subject's reaction to those are compared with each other categories. If the reaction to Probe are different with one to Irrelevant the subject is considered as he knows Probe. Although Word is often used as stimulus in a field of this study, we predict that Picture is better as stimulus in real case. So, in this study, we use Japanese word or picture as stimulus and compare the amplitude of P300 as reaction to those. Subjects are indicated to remember the Probe before experiment. And we carry out the experiment twice, one uses Word stimulus and the other uses Picture stimulus; those stimuli show same meaning. Comparing the results of those experiments, it is showed that task of Picture is better for CIT.
