Journal of Forensic Medicine

法医学杂志 ›› 2020, Vol. 36 ›› Issue (2): 229-232，238.DOI: 10.12116/j.issn.1004-5619.2020.02.015

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Application of Eye Tracker in Lie Detection

GE Fen-fen1,2, YANG Xiao-qing3, CHEN Yu-xing1, HUANG Hao-lan1, SHEN Xia-can1, LI Yan1, HU Jun-mei1   

  1. 1. West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610000, China; 2. West China School of Medicine, Sichuan University, Chengdu 610000, China; 3. School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610000, China
  • Online:2020-04-25 Published:2020-04-28

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Abstract: Objective To investigate the application value of eye tracking in lie detection. Methods The 40 subjects were randomly divided into two groups. The pupil diameter, fixation duration, points of fixation and blink frequency of the subjects in the experimental group in observing target stimulation and non-target stimulation were recorded with eye tracker after they accomplished the mock crime. The eye movement parameters of subjects in the control group were directly collected. The differences in eye movement parameters of the experimental group and the control group in observing target stimulation and non-target stimulation were analyzed by t-test. Pearson coefficient analysis of correlation between eye movement parameters that had differences was conducted. The effectiveness of eye movement parameters to distinguish between the experimental group and the control group was calculated by the receiver operator characteristic （ROC） curve. Results Participants from the experimental group had shorter average pupil diameter, longer average fixation duration and fewer fixation points （P<0.05）, but the differences in blink frequency had no statistical significance. The differences in the above indicators of the control group in observing target stimulation and non-target stimulation had no statistical significance. The average fixation duration showed a negative correlation with fixation points （r=-0.255, P<0.05）; the average fixation duration showed a negative correlation with average pupil diameter （r=-0.218, P<0.05）; the fixation points showed a positive correlation with average pupil diameter （r=0.09, P<0.05）. The area under the curve of average pupil diameter, average fixation duration and fixation points was 0.603, 0.621 and 0.580, respectively. Conclusion The average pupil diameter, average fixation duration and fixation points obtained by the eye tracker under laboratory conditions can be used to detect lies.

Key words:  forensic psychiatry, lie detection, eye movement, fixation, ocular, fixation point, pupil diameter