Memory Detection in Virtual Reality The Effect of Scene Modifications

Can your eyes give away your deepest secrets? In two preregistered studies, we examined whether eye movements toward modified areas of a crime scene enable to detect crime knowledge. After committing either a mock crime or an unrelated task, guilty (Study 1 n = 12; Study 2 n = 63) and innocent (Study 1 n = 21; Study 2 n = 74) participants viewed the crime scene in virtual reality to which several salient modifications were made. Guilty participants looked more (Study 1 d = 0.88; Study 2 d = 0.65) and earlier (Study 1 d = 0.66; Study 2 d = 0.52) at these modifications as compared with innocent participants. It was possible to significantly distinguish guilty participants from innocent ones based on their eye movements toward the modified areas (Study 1 area under the curve = 0.75; Study 2 area under the curve = 0.68). Furthermore, in Study 2, we added a third group of participants who were guilty but revisited the crime scene in virtual reality without modifications, to test the contribution of these modifications. We found that the guilty-modifications group looked significantly more at the modified areas than the guilty-no modifications group (d = 0.35), although from a Bayesian perspective this evidence was only anecdotal (BF₁₀ = 2.06). Despite the modest effect sizes, we argue that this approach has several important advantages in comparison to traditional memory detection tests.