I read about an interesting article about a study of liars.

A recent study by the Universtiy of Southern California compared generally honest people with chronic liars and found that 22% more white matter in the prefrontal cortex of liars' brain and 14.2% less gray matter. (For your knowledge, white matter is the brian's networking material. Gray matter is areas of the brain that are dominated by cell bodies.)

"The more networking there is in the prefrontal cortex, the more the person has an upper hand in lying. Their verbal skills are higher. They’ve almost got a natural advantage,"said Adrian Raine, a psychology professor at USC and co-author of the study.

"Pathological liars can’t always tell truth from falsehood and contradict themselves in an interview. They are manipulative and they admit they prey on people. They are very brazen in terms of their manner, but very cool when talking about this." Normally, when people make moral decisions, they are relying on the prefrontal cortex. Yet, liars have a 14% reduction in gray matter, that means that they are less likely to care about moral issues. "Having more gray matter would keep a check on these activities," Raine explained.

If you find yourself guilty when you tell a lie, congraduations, you are a normal, morally and pathologically.

source form: Liars' Brains Wired Differently by USC News.