Eye-Movement Study On Guilty Knowledge Test

The deception detection technology is an interdiscinplinary subject which involves psychology, biomedicine, interviewing technique, electronic circuits technology as well as basic knowledge of computer science. It dedicated to explore the hidden intention or deceptive response of the interviewer. The Guilty Knowledge Test (GKT) is a theoretically well-established lie detection paradigm with great potential in basic and applied science. The rationale underlying GKT is that it did not detect the lies per se, but to detect the different physiological reactions associated with crime-relevant information possessed by criminal other than innocents. Thus the GKT was regarded as a more scientific, cognitive-based psychophysiological measurement paradigm. Nonetheless, the GKT was disputed for it can not provide sufficient protections to the innocent who possessed guilty knowledge. Another limitation of previous research was that most GKT employed skin conductance response as physiological indicator, yet this indicator faced a few of practical obstacles. Therefore, to improve the efficiency of lie detection techniques, the current research focused on the aforementioned two questions: 1, to modify the question format of GKT and 2, to seek for more sensitive indicators.The current research employed eye-tracking system as lie detector, tried to use pupil response as indicators, combined with GKT and its variant as experimental paradigms, to investigate the validity of pupil-response based lie detection technique. The present research also aimed to emplore the role of individual component in GKT to choose more sensitive indicators and more efficient question formats to decrease the high false positivity of GKT.The current research consisted of three successive experiments. Participants acquired crime-relevant information during a mock crime scene. Experiment 1 measured and analyzed the criminals' pupil response to guilty information pictures (probe) and irrelevant pictures to test the role of cognitive component in GKT. Experiment 2 added an innocent group and changed the response mode from differences to "I do not know", to test the validity of pupil response indicator in classifying guilty and innocent participants. Experiment 2 also further tested the role of cognitive and deceptive component in GKT testing. Experiment 3 modified the GKT paradigm to Guilty Movement Test (GMT), to test the validity of pupil response in differentiating knowledged innocent from guilty participants. Experiment 3 also increased the number of high self-involvement questions to further test the self-referring effect in GMT paradigm.The conclusions are listed below:(1): The pupil response testified the cognitive and deceptive component in GKT paradigm;(2): The pupil response could classify different types of participants. Although the detection rate of knowledged innocents was lower compared to the SCR-based paradigm, the pupil response of guilty participants were larger than two types of innocent participants.(3): GMT paradigm had improved the GKT paradigm. It increased the detection rate of knowledged innocents. It also showed that there were influences of self-referring effect in addition to cognitive and deceptive component.