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Lie Detection
fMRI
Professor Sean Spence from the University of Sheffield has pioneered the use of functional magnetic resonance imaging (fMRI) to detect lies. fMRI scans work in real time and 'light up' active parts of the brain.
So far, the procedure is experimental, but it looks like it will be a promising tool in criminal investigation. In studies, subjects responded to questions under instructions to either lie or to be truthful. At the same time they were scanned.
The scans show that some regions of the pre-frontal cortex light up each time we fib. These are areas that suppress automatic responses. For example, you'll use these brain areas next time you have to suppress a verbal outburst in a public place. In a similar way, lying involves stifling your instinct to tell the truth.
In experimental conditions, the technology has proved over 90% accurate – far better than polygraph tests. Lie detection tests are already used regularly in parts of the US justice system, as well as by businesses, and UK trials are in progress with convicted sex offenders and benefit claimants.
Up until now though their accuracy has been open to debate because most of these detectors are measuring anxiety levels on the assumption that lying induces anxiety. But we know that for some people this simply isn't the case.
fMRI | The Polygraph | Trial by Fire
