Magnetic interference with the brain can make it impossible to lie, and polygraphs and "truth serums" will soon be obsolete, say Estonian researchers.
Inga Karton and Talis Bachmann worked with 16 volunteers who submitted to transcranial magnetic stimulation, which can stimulate some parts of the brain and not others.
The team discovered that when magnets were applied to either the right or left side of the dorsolateral prefrontal cortex in the front of the brain, depending on which side was stimulated, the subjects would either lie or tell the truth. But when magnetic interference was directed at the parietal lobe, their decision-making remained unchanged.
The volunteers were presented a series of coloured discs, and told they could tell the truth or lie about the objects' colours while half were being stimulated on the left and half on the right.
Results showed that the eight volunteers who had their left DPC stimulated lied more often, while the ones with the right DPC stimulated were more likely to tell the truth, researchers said.
The experiment was then repeated with the parietal lobe stimulated, and there was no effect.
"Spontaneous choice to lie more or less can be influenced by brain stimulation," researchers Karton and Bachmann wrote in Behavioural Brain Research.
Last year, researchers at the Massachusetts Institute of Technology also used powerful magnets to disrupt the area said to be the brain's "moral compass," situated behind the right ear, making people temporarily less moral.
Critics point out that study was only based on 16 volunteers, but it nonetheless indicates that despite common public assumptions, the sense of right and wrong is based not only on social constructs such as cultural or religious beliefs, but also our brain mechanisms.
"You think of morality as being a really high-level behaviour. To be able to apply a magnetic field to a specific brain region and change people's moral judgements is really astonishing," said Dr. Liane Young, who led the study.