A study out of the University of Southern California could give new meaning to the term "white lie."
Scientists found a 22 percent excess of white matter in the prefrontal cortex of pathological liars, versus normal subjects, after conducting Magnetic Resonance Imaging (MRI) on the brains of both groups. The prefrontal cortex is the top layer of the brain's front hemisphere; it is believed to handle cognitive functions such as thinking, learning and judging. White matter serves as electrical wiring, connecting brain cells to one another.
The study's lead author, University of Southern California (USC) doctoral student Yaling Yang, and its co-author, Adrian Raine, a psychology professor, focused on the prefrontal cortex after studies performed at the University of Hong Kong found increased brain activity in the area when people lied. They believe the excess of white matter may equip liars with the facilities to be more effectively deceitful.
Yang illustrates the point by describing the discrepancy in white matter growth during development in children with autism versus normal children. "Autistic kids, when they grow from age three to age 10, their white matter increases about 10 percent," she says. "But for normal kids, the increase is almost 50 percent. And as we know, autistic kids have trouble lying. And that's basically where our idea came from. White matter seems to give us the advantage when telling lies."
The researchers also found 15 percent fewer brain cells (or less gray matter) in liars versus normal subjects. In a statement released by USC, Raine related the deficit in grey matter volume to the impulsiveness of fibbers. "They've got the equipment to lie, and they don't have the disinhibition that the rest of us have in telling the big whoppers."
There is no standardized method for diagnosing someone as a pathological liar according to the current edition of the Diagnostic and Statistical Manual of Mental Disorders), the preeminent diagnostic text for behavioral scientists. Subjects were deemed liars if they passed one of five tests, which measured compulsive lying, conning, manipulative behavior, deceitfulness or malingering (faking illness to avoid work).
"It's their brain," says Yang. "It's their abnormality that makes them have that kind of behavior. They just have to do it, and they continue doing it, even knowing the consequences."
The USC study, published in the October issue of the British Journal of Psychiatry, has been labeled a "beginning study" because of its modest sample size of 49 subjects. Both Raine and Yang admit that more work needs to be done to support their conclusions.
"I think if this finding is replicable then our study might have an implication in, for example, police investigations," says Yang. "This would be a good technique for them to use on particular suspects; it's kind of like lie detection."
The research out of USC comes as music to the ears of Charles C. Dike, an assistant clinical professor in psychiatry at Yale University's School of Medicine. Dike cowrote an article in the September issue of the Journal of American Academy of Psychiatry and Law that called for more "critical attention" to be paid to pathological lying.
"What I understood from my reviews and research is that pathological liars lie for unknown reasons or for reasons that are not immediately obvious, that are not necessarily self-serving and that may even be damaging to themselves," says Dike. "I think there needs to be a lot more research in this area."
Yang agrees with Dike. She plans to experiment further and try to replicate and expound upon their initial findings.
"We are going to try to do a more sophisticated segmentation of the prefrontal area and see which part of the area is making the difference."
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