Detecting Concealed Familiarity Using Eye Movements: The Effect of Leakage of Mock Crime Details to Innocents

The present study examined the eye-tracking Concealed Information Test (CIT) in a mock crime scenario. Participants were instructed to either commit a mock crime on campus (guilty participants; n = 42), read an article about this mock crime (informed innocents; n = 45), or read an unrelated article (naïve innocent participants; n = 46). Afterward, all participants were presented with an eye-tracking CIT task. Based on preregistered analyses of participants’ gaze behavior, we were able to distinguish the guilty participants from the naïve innocents (area under the curve [AUC] =.71, 95% CI [.60,.82]). Interestingly, we were also able to distinguish the guilty participants from the informed innocent ones (AUC =.65, 95% CI [.53,.77]). Although these results are promising, the observed detection efficiency was lower than both previous eye-tracking CIT studies that used highly familiar stimuli as well as mock crime CIT studies relying on physiological measures.