London: Scientists have found that magnetic interference with the brain makes it impossible to lie, a discovery they say could be the most effective way to extract information from crime suspects unwilling to tell the truth.

Estonian researchers found that stimulating part of the front brain with magnets alters the simplicity of lying.

The team found that when magnets were applied to either the right or left side of the dorsolateral prefrontal cortex, found directly behind the forehead, it makes a person to lie or tell the truth, depending on which side was stimulated.

However, magnetic interference directed at another part of the brain, the parietal lobe, was found to have no impact on the people's decision-making, the researchers said.

"Spontaneous choice to lie more or less can be influenced by brain stimulation," study researchers Inga Karton and Talis Bachmann were quoted as saying by the Daily Mail.

For their study, published in the journal Behavioural Brain Research, the researchers recruited a small group of 16 volunteers who were given coloured disks.

Then, half of them were given magnetic stimulation on the right side of their prefrontal cortex, half on the left.

They then had two options: to lie about what colour their disks were, or tell the truth.

Results showed that the 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.

The experiment was repeated while a different brain region -- the parietal lobe --was stimulated and it produced no effect, the researchers said.

Last year, scientists at the Massachusetts Institute of Technology had found that magnets can also be used to disrupt the brain's "moral compass".

The region, which lies just behind the right ear, becomes more active when we think about other people's misdemeanours or good works.

In their experiment, the researchers were able to use powerful magnets to disrupt this area of the brain and make people temporarily less moral.

Dr Liane Young, who led the study, said: "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."

The moral compass lies in a part of the brain called the right temporo-parietal junction. It lies near the surface of the brain, just behind the right ear.

(Agencies)