Eye spy a liar: Assessing the utility of eye fixations and confidence judgments for detecting concealed recognition of people, places and objects

Abstract

Background: In criminal investigations, uncooperative witnesses might deny knowing a perpetrator, the location of a murder scene, or knowledge of a weapon. We sought to identify markers of recognition in eye fixations and confidence judgments while participants told the truth and lied about recognising people (Experiment 1), and places and objects (Experiment 2) that varied in familiarity. To detect recognition we calculated effect size differences in markers of recognition between familiar and unfamiliar items that varied in familiarity (personally familiar, newly learned). Results: In Experiment 1, recognition of personally familiar faces was reliably detected across multiple fixation markers (e.g., fewer fixations, fewer interest areas viewed, fewer return fixations) during honest and concealed recognition. In Experiment 2, recognition of personally familiar non-face items (places and objects) was detected solely by fewer fixations during honest and concealed recognition; differences in other fixation measures were not consistent. In both experiments, fewer fixations exposed concealed recognition of newly learned faces, places and objects but the same pattern was not observed during honest recognition. Confidence ratings were higher for recognition of personally familiar faces than unfamiliar faces, no other differences were detected. Conclusions: Robust memories of personally familiar faces were detected in patterns of fixations and confidence ratings, irrespective of task demands required to conceal recognition. Crucially, we demonstrate that newly learned faces should not be used as a proxy for real-world familiarity, and that conclusions should not be generalised across different types of familiarity.