Applicability and validity of the reaction time-based concealed information test in a prison sample

Purpose

The reaction time-based Concealed Information Test (RT-CIT) can be used to reveal crime-related memories based on an analysis of response latencies in a computerized task. While laboratory research shows high validity of the RT-CIT in student samples, only very few studies have been conducted with forensic target groups.

Methods

We investigated the applicability and validity of the RT-CIT in prison inmates and examined the influence of a response deadline (RD) on RT-CIT validity. In a within-subjects design, participants memorized a criminal activity and subsequently underwent two identical RT-CITs differing only in the length of the RD (2000 ms vs. 1000 ms). In the first experiment, the 2000 ms condition was always presented first and in the second experiment the order was switched.

Results

Results revealed large effect sizes and classification accuracies with both RDs and strong order effects with larger effects in the respective first RD conditions.

Conclusions

In sum, the RT-CIT has the potential for detecting concealed knowledge in forensic settings and even a relatively demanding RD of 1000 ms seems feasible for such samples. Further research should extend this investigation of the RT-CIT in forensic settings, preferably investigating the effects of faking attempts and increasing the ecological validity of the research design.