Equipment designed to detect a person’s trustworthiness by analysing their physical characteristics is unreliable and even harmful, warn a group of prominent international scientists. Serious questions need to be asked about whether security equipment and lie detectors actually deliver on their promises. 

Since the terrorist attacks of 9/11, security measures have been tightened throughout the world. Governments are continually searching for new ways to step up security, particularly at airports. The result is a dramatic rise in equipment and software which link physical signs of stress with the intention to deceive.

Sweaty palms have long been regarded as such a tell-tale sign. But a rise in temperature in the facial area is also said to be an indicator of lying. As is a change in the skin’s electrical charge. Even a shift in the sound and tone of the voice could be enough to convince the authorities that a passenger is up to no good. The lie detectors used at Moscow airport work on this very principle.

Alarm bells
But according to Ewout Meijer of the University of Maastricht, one of thirteen scientists who is raising the alarm about this trend, it is far from clear whether such equipment genuinely makes any difference to security.

"What’s wrong with this equipment is that it hasn’t actually been shown to work. And yet governments the world over are investing in it. That means spending a great deal of public money and saddling people with the consequences. You are inconveniencing people with equipment that doesn’t work."

As Ewout Meijer sees it, this is not only inconvenient, it is also dangerous. Since the equipment is not reliable, it generates a false sense of security. A terrorist who happens to be a cool customer will still be able to stroll through security undetected, while a perfectly innocent passenger who gets flustered at the sight of a uniform will be singled out time and time again without just cause.
 
Commercial interests
The problem is that detection equipment is manufactured and sold by commercial companies. They have no vested interest whatsoever in having the effectiveness of their machinery subjected to close scientific scrutiny. Especially if there’s a chance that this effectiveness will be called into question. In many cases, the producers’ claims are based on scientific research that is not made public, and which cannot therefore be verified. Meanwhile, the power of the manufacturers reaches far and wide. The International Journal of Speech, Language and Law recently withdrew a critical article on speech-analysis software when faced with the threat of legal action.

Evidence-based security
Ewout Meijer believes there is only one solution: to subject the security sector to checks which are every bit as stringent as those governing the pharmaceutical industry.

"No medicine can be brought onto the market without extensive research and until a series of committees have investigated the scientific evidence and decided that the medicine does indeed work. That’s what we call ‘evidence-based medicine’. We need to move towards a kind of ‘evidence-based security’ so that we are sure that all security equipment used in practice has been shown to work."

Ewout Meijer is far from being a sceptic. His main reason for championing such a quality label is because physical characteristics can actually be used to seek out the truth. Measuring the skin’s electrical resistance can show whether or not a suspect has knowledge of a certain crime. That is not the same as lie detection, but it can bring certain information to light. And above all, it is reliable, which is something that cannot be said of other methods.
 

RNW translation (dd)