Fixations and eye-blinks allow for detecting concealed crime related memories

• Published in: International journal of psychophysiology Vol. 88; no. 1; pp. 96 - 103
• Main Authors: Peth, Judith, Kim, Johann S.C., Gamer, Matthias
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2013
• Subjects: Adult; Analysis of Variance; Blinking - physiology; Blinks; Concealed Information Test; Crime - psychology; Eye movements; Eye Movements - physiology; Female; Guilty Knowledge Test; Humans; Lie Detection - psychology; Male; Memory; Memory - physiology; Mock crime; Psychophysics; ROC Curve; Statistics as Topic; Young Adult; Concealed Information Test; Mock crime; Eye movements; Blinks; Guilty Knowledge Test; Memory
• ISSN: 0167-8760; 1872-7697; 1872-7697
• DOI: 10.1016/j.ijpsycho.2013.03.003

The Concealed Information Test (CIT) is a method of forensic psychophysiology that allows for revealing concealed crime related knowledge. Such detection is usually based on autonomic responses but there is a huge interest in other measures that can be acquired unobtrusively. Eye movements and blinks might be such measures but their validity is unclear. Using a mock crime procedure with a manipulation of the arousal during the crime as well as the delay between crime and CIT, we tested whether eye tracking measures allow for detecting concealed knowledge. Guilty participants showed fewer but longer fixations on central crime details and this effect was even present after stimulus offset and accompanied by a reduced blink rate. These ocular measures were partly sensitive for induction of emotional arousal and time of testing. Validity estimates were moderate but indicate that a significant differentiation between guilty and innocent subjects is possible. Future research should further investigate validity differences between gaze measures during a CIT and explore the underlying mechanisms. •Gaze measures allow for revealing crime related knowledge in a traditional CIT.•Fixations seem to reflect recognition memory during stimulus perception.•Eye-blinks seem to reflect subsequent processes related to response monitoring.•Number and duration of fixations correlated with autonomic indices of recognition.