The Effects of Mental Countermeasures on Psychophysiological Memory Detection: Facilitating Orientation Is Easy, Stopping Inhibition Is Not

The concealed information test (CIT) is a highly valid method for the detection of concealed knowledge. It relies on differential physiological responses to critical compared to control items. Guilty individuals may however attempt to distort these reactions by using countermeasures (CMs). The present preregistered study compared two types of countermeasures: (a) a classical countermeasure designed to affect orientation to the critical items and, as such, skin conductance responses (SCRs), and (b) a novel countermeasure designed to affect inhibition attempts and, as such, the respiration line length (RLL) and heart rate (HR). The classical countermeasure reduced the SCR CIT effect, supporting the idea that guilty individuals can facilitate orientation. The novel countermeasure did not affect the RLL and HR measures. This suggests that guilty individuals might not be able to block their instinctive drive to inhibit physiological arousal. Thus, the RLL and HR seem more suitable for real-life cases where countermeasures are suspected.