Making Physiology Happen


Feb 2018: LieDetection-FacialRecognition

iWorx Systems, Inc.
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Did you know that when a person lies there are several “tells”, or signs, that a trained professional can use to judge whether the person is being truthful or not? The accuracy of detecting a lie is about 65% for an expert interrogator. But that job may soon fall to a machine rather than a person.eye tracking data

Research being carried out at various universities and research institutes had shown that when a person is lying about certain things, there are minute movements in the eye that are not there is the person is telling the truth. Testing has shown a lie detection accuracy rate of about 83%, way above what a person can do, even those who are fully trained experts.

Our eyes usually give us away when we lie due to their movement. Regular eye movement under questioning usually means we are being truthful, but if that movement changes suddenly and drastically then it’s probably going to be due to a lie being told. This is what an eye tracking system looks for when monitoring a person’s eyes during questioning about events that have happened or people they may know or have seen.

Researchers have previously monitored parameters such as GSR, heat changes in the body, heart rate and facial movement, but none seem to be as reliable for detecting lies as eye movement.  It has been demonstrated that people who are good at lying know how to control their movements and even their heart rate when telling a lie. However, it’s much more difficult to keep your eye movements in check, suggesting that eventually using eye tracking systems and software will become the ultimate lie detector that no one can beat.

Researchers may soon be able to tell whether a suspect is lying about recognizing someone they know. Using eye tracking technology, they found that people's eyes moved in a different pattern when looking at faces they recognized rather than ones they have never seen before.
The lead author of one of the studies, Ailsa Millen, states that: "Criminal accomplices often deny that they know other members in their networks.  However, if a co-conspirator denies recognition in this way, their eye movements when viewing photos of those suspects, may reveal this type of lie."

Researchers recorded the eye movements of participants while looking at digital color photographs of familiar and unfamiliar faces. Familiar faces included people the participants know in real life, famous celebrities and those only seen briefly before the experimental trials. Sometimes the participants lied about whether they recognized the photos, sometimes they told the truth. It has been found that people's eye movements were different when looking at photographs of faces they knew well compared to those they did not know, despite verbal responses denying recognition. When a participant looked at a face they recognized their eyes moved in a different pattern with fewer fixations. There is substantial evidence to suggest that this pattern is involuntary, which means it would be very hard to control or fake.
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