Body language can’t show a lie, say experts on airport security

Body language can’t show a lie, say experts on airport security

When it was revealed that investigations showed someone aboard MH370 had deliberately switched off the aircraft's communications system, many wondered if "not so innocent" passengers had been detected at the Kuala Lumpur International Airport before boarding the plane.

However, an article in The New York Times (NYT) pointed out that spotting deception is no easy task.

Although airport security screeners liked to think that they could read body language effectively, this may not be the case.

The United States Transportation Security Administration (TSA) has spent about US$1 billion training thousands of "behaviour detection officers", the NYT article said.

These officers are trained to look for facial expressions and other non-verbal clues which could identify terrorists.

But the NYT article said the TSA only inconvenienced tens of thousands of airline passengers annually, and has fallen for a classic form of self-deception, believing it can read liars' minds by watching their bodies.

“There’s an illusion of insight that comes from looking at a person’s body,” Nicholas Epley, a professor of behavioral science at the University of Chicago, told NYT. “Body language speaks to us, but only in whispers.”

The NYT article may explain how two Iranian nationals, using stolen Austrian and Italian passports – or any other passengers with ill intentions – had managed to board MH370 on March 8 without raising suspicion.

The article said that many assumed that liars would give themselves away by avoiding eye contact or by some nervous gestures.

“The common-sense notion that liars betray themselves through body language appears to be little more than a cultural fiction,” says Maria Hartwig, a psychologist at John Jay College of Criminal Justice in New York City.

Researchers have found that the best clues to deceit are verbal, but even these differences are usually too subtle to be discerned reliably, said the article.

One technique taught to law-enforcement officers is to watch the upward eye movements of people as they talk, based on the “neuro-linguistic programming” theory, that people tend to glance upward to their right when lying, and upward to the left when telling the truth.

Scientific experiments, on the other hand, have shown that generally, it is not easy to spot liars.

Flight MH370, carrying 12 crew members and 227 passengers, dropped off the radar at 1.20am on March 8, and has never been found since, despite a global effort involving 26 countries.

A massive hunt is now focused on the southern Indian Ocean following satellite images of possible debris from the plane. – March 24, 2014.