Polygraph test carries no credence


By Brendan Nicholson
National Security Correspondent
August 18, 2004

The polygraph, or lie detector, is considered experimental technology and Australian courts will not accept its tests as evidence.

The polygraph measures the automatic responses of the nervous systems of those being questioned and works on the basis that when people tell a lie, uncontrollable changes are apparent in their blood pressure, pulse rate and respiration. Tension is also reflected as minor shocks measurable on the skin.

After the arrest in 1999 of former Defence Intelligence Organisation officer Jean-Philippe Wispelaere, for trying to sell classified material, ASIO agreed to carry out a voluntary internal polygraph trial.

The agency and the government have since declined to comment on its progress.

The US Department of Defence considers the polygraph one of its most effective investigative tools, but respected US scientists have raised serious concerns about its accuracy.

The US National Academy of Sciences concluded in 2002 that someone who was a major security threat could beat the machine. Another who questioned its value was the notorious US spy Aldrich Ames, a CIA officer who betrayed his country to the Soviets for years and beat the polygraph.

Australian Polygraph Services, which carried out the test on Mike Scrafton, says the detector is an invaluable investigative tool. It says people don't beat the polygraph, they beat operators not properly trained.