It all comes down to gray and white--matter that is. A study conducted by Yaling Yang and Adrian Raine of the University of Southern California (USC) College of Letters, Arts and Sciences, showed there are structural abnormalities in the brains of pathological liars. The prefrontal cortex, an area located in the front of your brain, enables you to feel remorse and learn moralistic behavior. During the study, 108 people had an MRI performed. This test revealed that those prone to habitual lying had significantly more white matter than their counterparts, the honest test subjects. Those who were truthful had more gray matter. Although you cannot see the colors of someone's mind, there are other means of detecting a pathological liar.
According to Adrian Raine, USC psychology professor and co-author of the study, pathological liars will always contradict themselves. Their stories contain inconsistencies about occupation, education and family background. A pathological liar has a difficult time telling the difference between true and false, reality and their world of make believe. Eventually, these inconsistencies begin to unravel, making it easy to detect a liar from someone who is being truthful.
Regardless of how much white matter a person has--which enables him to lie without remorse--it does not necessarily make it an easy task for him. He needs to control his emotions, keeping his nerves at bay, as he conceals the truth. This can lead to physical behavior which displays his discomfort, such as shifting from one foot to another, an inability to sit still or moving his hands over his mouth and face frequently during your conversation.
According to Raines, one of the motives of a pathological liar is to manipulate you. If you pick up on her inconsistencies, or simply have a question she is not prepared to answer, her natural reaction may be one of defense. Remember, she is working hard to hide the truth form you; if she thinks you do not believe her, she may become extremely agitated or angry.
Repeat That, Please
A request to repeat accompanies his need to make you believe his lie as much as he does. If you happen to find something he says odd, or simply want to know more about the subject at hand, he may ask you to repeat the question. This gives him a moment or two to devise a lie he hopes you will believe. If this happens frequently throughout your conversation, beware.