Mark Henderson, science correspondent for The Times of London, reports on the use of magnetic resonance scans to detect concealed knowledge. Excerpt:
PATTERNS of brain activity that betray whether a person is lying have been identified, paving the way for brain scans in criminal investigations.
Scientists in the United States have discovered that several parts of the brain behave in distinctive fashion during attempts to conceal the truth and that this signature of deceit can be picked up by magnetic resonance scans.
The findings, by researchers at the University of Pennsylvania, suggest that the technique could be used as a sophisticated lie detector, much more accurate than today’s polygraph tests. The polygraph machine, which monitors breathing rate, pulse, blood pressure and perspiration for signs of nervousness, has been available for 80 years and is used in the US, particularly in espionage cases and by employers wishing to check job applicants’ honesty.
Its effectiveness is disputed by scientists and polygraph evidence is not admissible in British courts. It is prone to false positives because it works by measuring stress, which is often, but not always, a sign of deceitfulness. Many researchers believe that it can be fooled easily by an accomplished liar. The CIA double agent Aldrich Ames passed a series of such tests. Wen Ho Lee, the atomic physicist falsely accused of espionage, failed three times.
(Actually, to our knowledge, Wen Ho Lee “failed” only one polygraph “test” – the one administered by the FBI in February 1999.)