Facial lie-detector test to catch out fibbers

POKER-FACED liars could be caught out by a new technique that monitors tiny changes in expression and blood flow.

The lie-detector test developed by British scientists uses cameras and computer software to recognise untruthful faces.

The system picks up give-away clues such as lip-biting, slips of the tongue, nose-wrinkling, and blinking.

A thermal imaging camera is also used to measure flushing and blood-flow patterns around the eyes.

In future the system could be used covertly by police and border officials questioning suspect criminals or terrorists.

With hidden cameras positioned up to three metres away, suspects would not know they were being subjected to a lie-detection test.

Scientists hope soon to trial the technology at a British airport, although what form the study will take has not yet been decided.

Conventional “polygraph” lie detector tests involve wiring up subjects to equipment that measures blood pressure, pulse, heart rate, respiration and electrical skin activity.

But people have been known to “beat” the test using a range of techniques, such as controlling breathing and heart rate.

Professor Hassan Ugail, who heads the University of Bradford team behind the new test, said:

“When a person is being deceitful, when a person lies, there is increased brain activity and this is reflected in the face through involuntary facial expressions and blood flow.”