NCPA - National Center for Policy Analysis

Thermal Imaging May Detect Lying

January 3, 2002

Thermal imaging that can detect deceit could improve airport security. Researchers developed a high-definition thermal-imaging technique that can detect attempted deceit by recording the thermal patterns from people's faces. This technique has an accuracy comparable to that of polygraph examination by experts and has potential applications in remote and rapid security screening, without the need for skilled staff or physical contact. Using this technology, researchers analyzed the flushing response in people being startled. A flush around the eyes may expose dishonesty.

According to lie-detection expert and psychologist Charles Honts of Boise State University in Idaho, unlike polygraph tests, thermal imaging could be done without people knowing or granting permission. High-throughput security screening in airports or building entrances could use the technique remotely.

Volunteer criminals recruited by James Levine of the Mayo Clinic stabbed a mannequin and grabbed $20 from its hand. Using a high-definition heat-detection camera, Levine and his colleagues imaged their faces while interrogating them about the crime. The team found:

  • Guilty parties get hot around the eyes when lying, naive innocents stay cold.
  • The group correctly pinpointed over 80 per cent as either guilty or blameless.
  • This success rate is comparable to the existing polygraph method of lie detection, which measures changes in pulse rate, breathing and sweating.

Before surreptitious face surveillance arrives at the check-in, however, more reliability tests are needed. Polygraph detectors, although widely used, are still controversial and are accepted as evidence in only a few courts.

Source: Helen Pearson, "Liars Caught Red-Faced," Nature Science Update, January 3, 2002; Ioannis Pavlidis, Norman L. Eberhardt and James A. Levine, "Human Behavior: Seeing Through the Face of Deception, Nature, January 3, 2002.

For Nature summary


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