People who show very little emotion when they lie could soon be caught out by a new lie detector test which examines changes in facial expressions and blood flow.

The test, which could be piloted at an airport like Heathrow, Stansted, Gatwick or Luton, uses cameras and computer software to recognise faces that appear to be untruthful.

Tell-tale signs like lip-biting, slips of the tongue, nose wrinkling and blinking are all registered, while thermal imaging is used to measure flushing and blood-flow patterns around the eyes.

It is hoped that police and border officials could use this technology to detect suspected criminals or terrorists.

Given that the cameras can be positioned out of sight up to three metres away from the person in question, the suspect would not know that they are being monitored by the lie detector.

Despite the UK scientists who created this technology wanting to trial it at an airport in the UK, it has not yet been determined what form of study will be adopted.

In traditional polygraph lie detector tests, subject are wired up to equipment that measures blood pressure, pulse, heart rate, respiration and electrical skin activity.

The system is, however, far from 100% accurate as people can use a range of techniques, such as controlling breathing and heart rate, in order to “beat” the test.

However, subjects would have difficulty manipulating their body responses during the new test as they would not know when they were being scrutinised.

At an airport, the test could be used covertly on passengers at check-in or immigration.

Copyright © Press Association 2011

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