Global Trend

To Tell the Truth

The device that is widely used to detect lies today, the polygraph, is simply too unreliable. It is too inaccurate for the results to be admissible in court cases. A 2002 report by the National Research Council concluded that the polygraph can’t distinguish innocent people from guilty ones. In response, the U.S. Department of Energy began relying less on the use of the polygraph to conduct security checks on its employees.

The polygraph measures changes in heart rate, breathing, and other physiological responses to stress. In theory, these measures indicate that a person is lying. But research has found that the same responses can be triggered by fear, anxiety, and anger, even when the person is telling the truth. At the opposite extreme, a liar who teaches himself to remain calm while hooked up to the machine can appear to be telling the truth.

Now, according to a report in New Scientist, a new lie-detection device is being developed at the U.S. Department of Defense Polygraph Institute. Because it does not require the subject to be hooked up to electrodes, tubes, and blood-pressure cuffs, it should provoke less stress ? and fewer “false positive” readings for fabrications.

The new technology is called “thermal facial imaging.” It uses a camera pointed at the subject’s face. Employing high-resolution infrared imaging, it reveals what is happening below the surface of the skin. Specifically, it monitors the flow of blood through the blood vessels. When the subject tells a lie, the blood moves in tell-tale patterns.

For example, the unit’s operators look for bright red circles around the eyes. This betrays the “fight-or-flight response,” which would be typical of a person confronted with a question that requires a lie.

This conclusion is strongly supported by research by James Levine of the Mayo Clinic and Loannis Pavlidis of the University of Houston in Texas. Their studies revealed that when a person is startled or afraid, blood flows away from unimportant areas in the head, such as the cheeks, and toward crucial areas where it’s needed most, like the eyes.

In the study, which was published in The Lancet, the researchers used a thermal camera to see what happened when subjects were startled by a metal plate crashing to the floor. In every instance, blood rushed to the person’s eyes.

In a related study, Levine and Pavlidis asked people to make up stories. Then, they asked questions designed to reveal that they were lying. Once again, the camera showed that blood rushed to the eyes, demonstrating a solid link between the fib and the facial response.

Levine and Pavlidis have joined with Andrew Ryan at the Polygraph Institute in several experiments to determine if they can detect liars in the aftermath of a staged “crime.” In the experiments, subjects participate in a fake event and are then asked to try to deceive the questioner. With the camera focused on them, the method identified liars 84 percent of the time.

Further studies will be needed, but if the technology continues to yield highly accurate results, we foresee three major developments:

First, this type of accurate lie detector will be quickly rolled out for use in military and homeland security applications. The military could improve its effectiveness at interrogating prisoners of war. Air marshals and border guards could more effectively identify terrorists as they attempted to enter the country.

Second, the legal system would be transformed by technology that could identify when a person was lying. If judges could be relatively certain whether a defendant or a witness was telling the truth, the savings in legal costs and in wrongful convictions would be immense.

Third, private businesses using thermal facial imaging could dramatically improve applicant-screening processes. Corporations could improve their screening of job applicants to weed out embezzlers, hackers, drug abusers, and other undesirable employees that cost employers billions of dollars every year.

References List :
1. New Scientist, March 12, 2005, “Its Written All Over Your Face,” by Susan Gaidos. Copyright 2005 by Reed Business Information, Ltd. All rights reserved.2. The Lancet, June 2, 2001, “The Face of Fear,” by J. Levine, I. Pavlidis, and M. Cooper. Copyright 2001 by Elsevier Limited. All rights reserved.