The experimental study examines whether gaze behavior(blinking, eye aversion, eye contact) which has been universally believed to a deception cue is a reliable deception indicator in an interpersonal interrogative situation. This experiment was conduc ...
The experimental study examines whether gaze behavior(blinking, eye aversion, eye contact) which has been universally believed to a deception cue is a reliable deception indicator in an interpersonal interrogative situation. This experiment was conducted from March through May in 2017. 100 college and graduate students (41 males and 59 females) enrolled in a large-size university located in Busan were participated in this experiment. All participants were recruited through both a recruiting poster and class announcement. All participants were randomly assigned to the two conditions (truthtelling vs. lying) without gender balance. They were given a $10 value gift card as reward of their participation. The age of the participants ranged from 20 to 38 years with an average of 23.39 (SD = 2.55). Most participants were right-handed (n = 82), left-handed (n = 10), and ambidextrous (n = 8). Participants were told that first participants would have an opportunity to take $100 value bills. They were then interrogated about their casual life and their behaviors associated with money theft. During the interrogation, participants must convince the interrogator that they did not take the cash regardless of whether they had taken the bills or not. The interrogation took about 7 minutes. All interrogations were recorded in facial (from upper chest to head) using a camera, each capturing 30 frames per second and analyzed by the conversational phases (e.g., listening, thinking, answering, and monitoring) and frame by frame. Of the 17 questions for the interrogation, two questions were selected for coding and analysis. One open ended question from the baseline set where the participants were asked questions unrelated to the crime served as a measurement for normal eye behavior of the participants. Another open question that was directly related to the money theft was designed to provide absolute truth or lies. Gaze behavior includes eye contact, eye aversion, and blinking. When participant looked at the interrogator straightly, it was scores as eye contact. The position of the eye looking at the interrogator was established and any movement that deviated from that position was scored as gaze aversion. When participants blinked in less than 15 frames (1/2 second), it was scored as blink. However, if they blinked more than 16 frames, it was included in gaze aversion (Ekman, FACS manual reference) since blinking exceeding 1/2 second is an eye closure which is part of gaze aversion. The amount of time of each eye behavior was calculated on the conversational phase. The amount of time of each eye behavior during the listening phase, and the answering phase is the period the interrogator asked the question, and while the participant answered the question respectively. The amount of time for the thinking phase was measured from the period when the interrogator stopped asking the question until the participants started the response, and included pauses, hesitations, and requests. The amount of time for observing was measured from the point when the participant stopped answering until the interrogator started asking the next question. The dependent variable was the proportion of gaze aversion, which is calculated by the number of frames of gaze aversion divided by the number of total frames multiplying 100 during the listening, thinking, speaking, and observing phase for interrogation respectively. Results reveal that there was no statistic significance between gaze behavior and deception. However, the results found that when lying than when telling the truth, participants are more likely to maintain less gaze aversion during the thinking phase of the critical period. The findings of this study implicate that gaze behavior as a deception cue might be used for lie detection.