How Vulnerable is the Reaction Time Concealed Information Test to Faking?

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.