Frequent liars’ brains look different than non-liars’

In the lexicon of lying, there are white lies and bare-faced lies. Facts can be fudged, forged or shaded. There are fibbers, fabricators and feckless fabulists. By whatever clinical term, the truth simply is not in some people.

Now scientists have an anatomical inkling of why.

A new study from the University of Southern California, published in the October issue of the British Journal of Psychiatry, suggests that the talent for compulsive deception is embedded in the structure of the brain itself.

People who habitually lie and cheat – pathological liars – appear to have much more white matter, which speeds communication between neurons, in the prefrontal cortex than normal people, the researchers found. They also have fewer actual neurons.

To seek a liar’s neural signature, the researchers recruited 108 volunteers, then sorted them into groups based on a battery of psychological tests designed to determine how often they lied, used aliases, cheated, conned people, malingered or gave false reports to police. The screening tests were developed by clinical psychologists to diagnose a variety of antisocial personality disorders and assess levels of deceitfulness.

The volunteers were then scanned using magnetic structural imaging to obtain detailed anatomical images of their brain tissue.

The group of compulsive liars had 25.7 percent more white matter in the prefrontal cortex and 14.2 percent less gray matter than the normal control group.

The differences affect a portion of the brain located just behind the forehead that enables people to feel remorse, learn moral behavior and plan complex strategies.

The surplus of connections between neurons might enable those people to be more adept at the complex neural networking that underlies deceit. Lying is hard work, and such brains may be better equipped to handle it, the researchers said.

“Lying is cognitively complex,” said USC psychologist Adrian Raine, the senior scientist on the research project. “It is not easy to lie. It is certainly more difficult than telling the truth. Some people have a biological advantage in lying. It gives them a slight edge.”