P300‐Based Memory Detection Applied to a Mock Terrorism Scenario Using the Complex Trial Protocol With Multiple Pictorial Stimuli

ABSTRACT The Complex Trial Protocol (CTP), a P300‐based Concealed Information Test (CIT), is an innovative tool that can be used to identify individuals who possess crime‐related information. We tested the CTP in a mock terrorism scenario with three different probes. Undergraduate participants ( n = 41) were randomly assigned to one of three groups: Innocent Control (IC), Simply Guilty (SG), and Guilty Countermeasure (GCM). Individuals in the SG and GCM groups underwent a mock terrorism scenario and were exposed to three pictorial probes: the face of an accomplice, the crime scene, and the mock explosive device. The GCM group performed a memory suppression countermeasure. Based on the AUCs generated, the CTP showed a good to very good predictive ability ranging from 0.63 to 0.94 depending on the probe presented. Attempting to suppress information had the opposite effect of generating slightly higher P300 amplitudes than in SG individuals. Stimuli quality and ecological issues are discussed.