The P300 brainwave is an event related potential (ERP) component elicited in the process of target detection. This study used the P300 in an attempt to classify members of a group who might know about a “crime.” Participants saw three types of pictures: Targets (modes of transportation), Standards (animals), and Crime (objects stolen). Participants identified when a target was shown. Prior to the task, two participants were randomly selected to view the “Crime” pictures without the experimenters knowledge. ERPs were calculated at 9 electrodes on the central portion of the scalp. Results showed a significantly larger P300 for target compared to standard stimuli. Of the 12 potential “Suspects”, eleven were correctly classified using the difference between the responses to the standards and crime pictures. A larger P300 to “Crime” pictures suggests knowledge of the crime. This study demonstrates the potential for using ERPs to detecting specific knowledge in uncertain circumstances.
