MRI brain scan the ultimate lie detector

BRAIN imaging techniques that can reveal when a person is lying are now reliable enough to identify criminals with near faultless accuracy.

Neuroscientists using magnetic resonance imaging (MRI) scans - which provide a computer-generated picture of the brain's workings - have developed a near 100 per cent accurate formula to separate lies from the truth, a report in the journal Nature reveals.

The researchers believe that their test is now ready for real-life scenarios.

The test works by monitoring the frontal lobes of the brain. When somebody lies, their brain inhibits them from revealing the truth, and this makes the frontal lobes more active. By analysing the brain activity during scenarios in which subjects tell both truths and lies, they have developed an algorithm that can identify each response with 99 per cent accuracy. The team gave volunteers an envelope containing two playing cards and $20. Subjects could keep the money if they lied convincingly in the tests.

One of the scientists who worked on the study, Rugen Gur, said: "A lie is always more complicated than the truth. You think a bit more, and MRI picks that up."