Effect of the enhanced protocols on response time-based concealed information test using Japanese word stimuli

Abstract

Enhanced protocols were proposed for improving detection rate of the response time-based concealed information test (RT-CIT), however it is unclear whether or not it is effective when the stimuli are Japanese words. This study investigated its effectiveness by two experiments: Self-related item was used for probe in experiment 1, and mock-crime related item was used for probe in experiment 2. In both experiments, participants were asked to push [I] button for the target and three fillers (e.g. FAMILIER, KNOWN) and [E] button for the probe, irrelevant, and other six fillers (e.g. UNFAMILIER, UNKNOWN). Only in experiment 2, standard RT-CIT and enhanced RT-CIT were both conducted and compared their results. As results, RTs were significantly delayed for probe compared to those for irrelevant in enhanced RT-CIT in both experiments, but not different in standard RT-CIT in experiment 2. Based on the results of both experiments, the effectiveness of the enhanced RT-CIT using Japanese word stimuli was discussed.