Abstract

This study investigated the method resistant to information leakage in P300-based concealed information test using misleading information and Korean sentences. The misleading information is intentionally introduced to participants as a crime-related item. Participants acquired crime-related knowledge either by committing mock crime (guilty group, n=58) or watching a video that describes a mock crime (informed-innocent group, n=53). Each group was divided into three conditions by exposing to misleading information before the concealed information test : control, 1-misleading information, 2-misleading information. During the concealed information test, the sentence stimuli were presented in subject-object-verb order. There was a significant difference in P300 amplitude between the probe and irrelevant stimuli for object and verb elements regardless of misleading information condition in the guilty group. In the informed-innocent group, the probe stimulus elicited larger P300 amplitude compared to irrelevant stimuli for object and verb elements only in the control condition, but not in the 1-misleading information and 2-misleading information condition. These results suggest that the misleading information in the P300-based concealed information test is effective in reducing false positive outcomes of informed-innocents, even that the number of misleading information increases.