The Lie Detector you’ll Never Know is There

By Paul Marks

THE US Department of Defense has revealed plans to develop a lie detector that can be used without the subject knowing they are being assessed. The Remote Personnel Assessment (RPA) device will also be used to pinpoint fighters hiding in a combat zone, or even to spot signs of stress that might mark someone out as a terrorist or suicide bomber.

In a call for proposals on a DoD website, contractors are being
given until 13 January to suggest ways to develop the RPA,
which will use microwave or laser beams reflected off
a subject’s skin to assess various physiological parameters
without the need for wires or skin contacts.

The device will train a beam on
“moving and non-cooperative subjects”,
the DoD proposal says, and use the reflected signal
to calculate their pulse, respiration rate and changes in
electrical conductance, known as the “galvanic skin response”.
“Active combatants will in general have heart, respiratory
and galvanic skin responses that are outside the norm,”
the website says.

Because these parameters are the same as those assessed
by a polygraph lie detector, the DoD claims the RPA will also
indicate the subject’s psychological state: if they are agitated
or stressed because they are lying, for example.

So it will be used as a
“remote or concealed lie detector during prisoner interrogation”.
But finding ways to fulfil the DoD’s brief will pose a practical
challenge, says Robert Prance, an electrical engineer
at the University of Sussex, UK, who specialises
in non-invasive sensors.

“They might capture breathing rate with an infrared laser
that senses chest vibration, but how they will measure a pulse
through clothes, for instance, is a very big question.”
If the RPA is ever produced, it is likely to prove controversial.
A remote lie detector would face even more difficulties than
standard polygraph tests, which were themselves the subject
of a damning 2003 report from the US National Academy of Sciences.

“There is no way a polygraph test can be carried out usefully
without the subject knowing, because you actually want
the person to worry about certain questions,”
says Bruce Burgess, an examiner with polygraph firm
Distress Services of Leatherhead, Surrey, UK.

But Steve Wright, a conflict analyst at Leeds Metropolitan
University, UK, raises the prospect of people identified
as suspects by the device being captured and subjected
to secret “prisoner rendition” as a result. And he warns
that the RPA could introduce a “chill factor” into everyday life.