Can We Really Catch Terrorists? Applying The Science of Deception Detection at Airports
Favorite Excerpts (via Nature)
Yet a growing number of researchers are dubious — not just about the projects themselves, but about the science on which they are based. “Simply put, people (including professional lie-catchers with extensive experience of assessing veracity) would achieve similar hit rates if they flipped a coin,” noted a 2007 report1 from a committee of credibility-assessment experts who reviewed research on portal screening.
“No scientific evidence exists to support the detection or inference of future behaviour, including intent,” declares a 2008 report prepared by the JASON defence advisory group. And the TSA had no business deploying SPOT across the nation’s airports “without first validating the scientific basis for identifying suspicious passengers in an airport environment”, stated a two-year review of the programme released on 20 May by the Government Accountability Office (GAO), the investigative arm of the US Congress.
Most credibility-assessment researchers agree that humans are demonstrably poor at face-to-face lie detection. SPOT traces its intellectual roots to the small group of researchers who disagree — perhaps the most notable being Paul Ekman, now an emeritus professor of psychology at the University of California Medical School in San Francisco. In the 1970s, Ekman co-developed the ‘facial action coding system’ for analysing human facial expressions, and has since turned it into a methodology for teaching people how to link those expressions to a variety of hidden emotions, including an intent to deceive. He puts particular emphasis on ‘microfacial’ expressions such as a tensing of the lips or the raising of the brow — movements that might last just a fraction of a second, but which might represent attempts to hide a subject’s true feelings. Ekman claims that a properly trained observer using these facial cues alone can detect deception with 70% accuracy — and can raise that figure to almost 100% accuracy by also taking into account gestures and body movements. Ekman says he has taught about one thousand TSA screeners and continues to consult on the programme.
Ekman’s work has brought him cultural acclaim, ranging from a profile in bestselling book Blink — by Malcolm Gladwell, a staff writer for The New Yorker magazine — to a fictionalized TV show based on his work, called Lie to Me. But scientists have generally given him a chillier reception. His critics argue that most of his peer-reviewed studies on microexpressions were published decades ago, and much of his more recent writing on the subject has not been peer reviewed. Ekman maintains that this publishing strategy is deliberate — that he no longer publishes all of the details of his work in the peer-reviewed literature because, he says, those papers are closely followed by scientists in countries such as Syria, Iran and China, which the United States views as a potential threat.