Fibbers watch out:new researchat the University of Pennsylvania has shownthat brain scans are significantly more likely to spot lies than traditional lie detectors.
It's the first time the two technologies have been compared in acontrolled experiment. A polygraph, commonly known as alie detector, measures physiological activity such as electrical skin conductivity, heart rate and respiration, with the idea being that these will spikewhen someone is lying. The brain scans, on the other hand, usefunctional magnetic resonance imaging (fMRI) to monitor brain activity by detecting changes associated with blood flow. Previous studies have shown that when people are lying, areas of the brain linked to decision making 'light up'.
The researchers asked28 participants to choose a number between three and eight. They were then instructed to answer "no" to questions about all of the numbers, making one of their six answers a lie. The tests were carried out while the participants were either hooked to a polygraph or lying inside an MRI scanner, and the results were compared to find out which technology was most effective at spottingdeception.
The brain scans were found to be 24 per centmore accurate at detecting lies than the polygraph. What's more, when the polygraph and fMRI both agreed on the lie, they were 100 per centcorrect.
This brings up the controversial question of whether brain scans could be an effective way to catch criminals. "While the jury remains out on whether fMRI will ever become a forensic tool, these data certainly justify further investigation of its potential,"says Daniel D. Langleben, lead author of the study.
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