Like many other things in life, a person's lying skills get better with practice, according to a new study, which suggested that repeated lying overcomes our tendency for truth, making subsequent lying easier-and possibly undetectable.
Neuroimaging studies have shown that that brains show more activity when people lie than when they are not, particularly in the prefrontal cortex, suggesting that lying requires extra cognitive control and inhibition of truth-telling, reports New Scientist.
To test whether the brain's so-called 'dominant truth response' can be changed, Bruno Verschuere of Ghent University in Ghent, Belgium, and colleagues studied three groups of students.
The researchers found that the frequent liars became more adept at lying. The normal difference in reaction times between telling the truth and lying disappeared.
"In people who lie a lot in real life [such as pathological liars], this dominant truth response might not be as strong as we theorise," said Ewout Meijer of Maastricht University in the Netherlands.
Meanwhile, Scott Lilienfeld of Emory University in Atlanta, Georgia, said that the results have raised the intriguing possibility that at least some lie detector measures may be relatively ineffective for practiced liars, including psychopaths.
"Lie detector tests are most often used on people suspected of crimes, who have higher rates of psychopathic characteristics - including pathological dishonesty - than other individuals," he said.
Meijer added, "The finding implies that peppering a lie-detector test with simple questions designed to elicit a truthful response will strengthen the brain's truth response, making it harder for someone to lie. This will increase the accuracy of such tests."