How vulnerable is the reaction time concealed information test to faking?

Abstract

The reaction time-based Concealed Information Test (RT-CIT) can be used to detect information a suspect wishes to conceal. While it is often argued that it is easily faked, empirical research on its vulnerability to faking is scarce. In three experiments, we tested whether receiving faking instructions enables guilty participants to fake an innocent test outcome in an RT-CIT. In Experiment 1, when not using a response deadline, we found the RT-CIT to be vulnerable to faking (d = 1.06). Experiment 2 showed that when using a response deadline, faking was ineffective (d = −0.25). Critically, Experiment 3 replicated these findings within one between-subject design, showing again a faking effect when no response deadline was used (d = 1.08) that vanished with the use of a response deadline (d = −0.56). By providing suggestions for the development of a faking detection algorithm, we hope to stimulate further research in this area.

Speed versus accuracy instructions in the Response Time Concealed Information Test

“…However, our findings at least suggest that it is also unlikely that the test will be rendered less effective by the examinees' deliberate focusing on either accuracy or on speed. From this perspective, the present study contributes to the accumulating evidence that (as long as response time limits are ensured) the RT-CIT cannot be effectively manipulated (Norman et al, 2020;Suchotzki et al, 2021).…”

“…Similarly, if there is no requirement for a minimum number of correct responses, participants can simply press any response key without paying attention to the items, rendering the test useless again. A recent study investigated the faking of the RT-CIT and confirmed that, indeed, the lack of a response time limit makes the test fakeable, whereas the implementation of such a deadline diminishes this faking effect (Suchotzki et al, 2021).…”

“…For example, instead of, or in addition to, presenting participants with different instructions regarding a focus on speed or accuracy, such a study could make use of different response time deadlines. The ideal response deadline for the RT-CIT is unknown (Suchotzki et al, 2021) and a study with a deadline of, for example, 800 ms in the speed group (cf., e.g., Lukács et al, 2017) and a deadline of, for example, 1,500 ms in the accuracy group (cf., e.g., Suchotzki et al, 2021) seems reasonable. Additionally, in the accuracy group one could make use of an error feedback following incorrect trials, as used in our experiment, while in the speed group such a feedback could be omitted.…”

“…shows, on the one hand, that such instructions are unlikely to benefit this method, but, on the other hand, it also suggests that related deliberate manipulation (focusing on speed or on accuracy) is unlikely to decrease the efficiency of the RT-CIT -contributing further evidence to the RT-CIT's resistance to faking (Norman et al, 2020;Suchotzki et al, 2021). More generally, these findings contribute further evidence that the RT-CIT is not influenced by relatively minor differences in task instructions (Lukács & Ansorge, 2019).…”

“…Unfortunately, conflicting as they may be, both speed and accuracy are necessary to some SPEED VS ACCURACY IN THE RT-CIT 9 degree. If participants are given no time limit, they can fake the test by deliberately making their responses very slow to irrelevants (Suchotzki et al, 2021). If participants are allowed to make many mistakes, it would also allow them to simply not pay attention to the items in the task (e.g., just press random keys whenever a stimulus appears, without even identifying the stimulus first).…”