January 3, 2002. Copyright 2001. Graphic News. All rights reserved.

Camera that can spot liars

LONDON, January 3, Graphic News: A heat-sensing camera trained on peopleÕs faces was able to detect liars in a study that hints at a way of spotting terrorists at airports. 

In six of eight people who lied, a high-resolution thermal imaging camera detected a faint blushing around their eyes that U.S. scientists said is evidence of deception. The researchers, writing in the journal Nature, reported that the new test could be used under cover at airports to identify potential terrorists. 

ÒThere is an urgent need to devise technologies that can be used for automated, high-throughput screening to identify individuals intending to perform acts of terrorism,Ó said team leader, James A. Levine, an endocrinologist at the Mayo Clinic in Rochester, Minnesota.

Such facial imaging, he said, could provide a simple and rapid way of scanning people being questioned at airports or border crossings. At present, airports have to rely on a passengerÕs response to brief questions such as: ÒDid you pack your own bags?Ó

The experiment involved 20 Army recruits. They were randomly assigned to either stab a mannequin and take a $20 bill from its clothing, or not carry out this staged crime. 

The recruits were then filmed with the thermal imager as they were subjected to the same questions, with the mannequin-robbers instructed in advance to lie about their theft. 

Levine explained that the blushing is the thermal signature of the primitive Òfright-flightÓ response that arises when people lie. The tiny hot spots -- which are invisible to the naked eye -- are triggered because adrenaline is released, relaxing blood vessels in the face.

Using the equipment, the scientists managed to correctly identify over 75 percent of the ÒcriminalsÓ as either guilty or blameless. This success rate is comparable to the existing polygraph, or lie detector test, which measures changes in cardiovascular activity, breathing and sweating. 

Polygraphs, although widely used, are still controversial and are accepted as evidence in only a few courts, including those in some U.S. states, Israel and Japan. Polygraph testing also requires a subjectÕs consent plus time and skill to interpret data.

High-throughput security screening in airports or building entrances could use the technique remotely. "Thermal imaging could be done without people knowing," explains lie-detection expert and psychologist Charles Honts of Boise State University in Idaho.

Levine conceded the experiment was small but said the findings warrant Òaggressive investigationÓ for potential security applications. His team is planning additional tests.

/ENDS

Source: Nature, Associated Press