People lie for different reasons. Some lie to make themselves appear more successful. Some lie to cover an embarrassing situation or to gain acceptance. Some people lie simply out of a habit that began in early childhood to reduce stress. There is medical evidence that a pathological liar has a different structure in the brain that leads him to lie more often.
There are two distinctly different types of lying. Pathological lying is manipulative lying so that the person can get his way. Pathological liars have little regard for the feelings of others or the morality of their lies. Pathological lying is frequently associated with another mental disorder. Compulsive lying is often referred to habitual and chronic lying, which is lying about many things simply out of habit. Both types of lying are believed to begin during childhood.
A study by Yang et al., published in the British Journal of Psychiatry in 2007, found that brain scans on pathological liars showed structural differences in the prefrontal cortex of the brain. This area of the brain controls morality, honesty and remorse. In pathological liars, this area has a higher amount of white matter and a lower amount of gray matter. In this area of the brain, white matter is possibly associated with increased brain activity, and gray matter is associated with the controls needed for moral behavior.
Pathological liars often confuse truth and falsehoods and, during a structured interview, are inconsistent in their responses. Pathological liars may believe their lies are the truth. Pathological liars are intelligent, manipulative and may be self-centered. It is unknown if pathological lying is controllable by the individual. It is possible that a pathological liar may believe his lies to the point that he is delusional.
There is conflicting information regarding the difference between a pathological liar and a compulsive or habitual liar. In the three different references used for this article, the definition of a pathological liar and compulsive or habitual liar often appear to be the same. The difference in brain structure, or clinical difference, may be the only true difference between pathological and habitual, or compulsive, lying.
The ability to identify a pathological liar based on brain function may be of use in the criminal justice system to help determine the validity of a statement by a witness or potential suspect. There may also be value in employee screening to determine the best applicant for positions requiring honesty and trust. In the future, medications may be able to be developed to counteract the structural differences of pathological liars and provide insight into treatment options such as therapy with pharmaceuticals or simply therapy as in the case of compulsive, or habitual, lying.