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   First Evidence Of Brain Abnormalities Found In Pathological Liars   
   Date:   
   October 2, 2005   
   Source:   
   University of Southern California   
   Summary:   
   A USC study found the first evidence of brain abnormalities - specifically in   
   the prefrontal cortex - in pathological liars. While more research is needed,   
   the findings indicate a neurobiological basis for habitual lying.   
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   A three-dimensional MRI image of the brain.   
   Credit: Image courtesy of University of Southern California   
      
       
   While previous research has shownthat there is heightened activity in the   
   prefrontal cortex - the areaof the brain that enables most people to feel   
   remorse or learn moralbehavior - when normal people lie, this is the first   
   study to provideevidence of    
   structural differences in that area among pathologicalliars.   
   The research - led by Yaling Yang and Adrian Raine, bothof the USC College of   
   Letters, Arts and Sciences - is published in theOctober issue of the British   
   Journal of Psychiatry.   
   The subjectswere taken from a sample of 108 volunteers pulled from Los   
   Angeles'temporary employment pool. A series of psychological tests   
   andinterviews placed 12 in the category of people who had a history ofrepeated   
   lying (11 men, one woman); 16 who    
   exhibited signs ofantisocial personality disorder but not pathological lying   
   (15 men, onewoman); and 21 who were normal controls (15 men, six women).   
   "Welooked for things like inconsistencies in their stories aboutoccupation,   
   education, crimes and family background," said Raine, apsychology professor at   
   USC and co-author of the study.   
   "Pathologicalliars can't always tell truth from falsehood and contradict   
   themselvesin an interview. They are manipulative and they admit they prey   
   onpeople. They are very brazen in terms of their manner, but very coolwhen   
   talking about this."   
   Aside from having histories of conningothers or using aliases, the habitual   
   liars also admitted tomalingering, or telling falsehoods to obtain sickness   
   benefits, Rainesaid.   
   After they were categorized, the researchers used MagneticResonance Imaging to   
   explore structural brain differences between thegroups. The liars had   
   significantly more "white matter" and slightlyless "gray matter" than those   
   they were measured against,    
   Raine said.   
   Specifically,liars had a 25.7 percent increase in prefrontal white matter   
   comparedto the antisocial controls and a 22 percent increase compared to   
   thenormal controls. Liars had a 14.2 percent decrease in prefrontal graymatter   
   compared to normal controls.   
   More white matter - thewiring in the brain - may provide liars with the tools   
   necessary tomaster the complex art of deceit, Raine said.   
   "Lying takes a lot of effort," he said.   
   "It'salmost mind reading. You have to be able to understand the mindset ofthe   
   other person. You also have to suppress your emotions or regulatethem because   
   you don't want to appear nervous. There's quite a lot todo there. You've got   
   to suppress the truth.   
   "Our argument is thatthe more networking there is in the prefrontal cortex,   
   the more theperson has an upper hand in lying. Their verbal skills are   
   higher.They've almost got a natural advantage."   
   But in normal people,it's the gray matter - or the brain cells connected by   
   the white matter- that helps keep the impulse to lie in check.   
   Pathological liarshave a surplus of white matter, the study found, and a   
   deficit of graymatter. That means they have more tools to lie coupled with   
   fewer moralrestraints than normal people, Raine said.   
   "They've got theequipment to lie, and they don't have the disinhibition that   
   the restof us have in telling the big whoppers," he said.   
   "When peoplemake moral decisions, they are relying on the prefrontal cortex.   
   Whenpeople ask normal people to make moral decisions, we see activation inthe   
   front of the brain," he explained. "If these liars have a 14percent reduction   
   in gray matter, that    
   means that they are less likelyto care about moral issues or are less likely   
   to be able to processmoral issues. Having more gray matter would keep a check   
   on theseactivities."   
   The researchers stopped short of asserting that these structural differences   
   account for all lying.   
   "This is one of the components," Raine said.   
   "The findings need to be replicated and extended to other parts of the brain.   
   What are the other neurobiological processes?   
   "Wehaven't had studies like this. It's exciting to us because it's abeginning   
   study, but we need a lot more to flesh out this discovery."   
   Yang,the study's lead author, said the findings eventually could be used   
   inmaking clinical diagnoses and may have applications in the criminaljustice   
   system and the business world.   
   "If [the findings] can bereplicated and extended, they may have long-term   
   implications in anumber of areas," said Yang, a doctoral student in the USC   
   departmentof psychology's brain and cognitive science program.   
   "Forexample, in the legal system they could potentially be used to helppolice   
   work out which suspects are lying. In terms of clinicalpractice, they could   
   help clinicians diagnose who is malingering -making up disability for   
   financial gain. "And also in    
   business, theycould assist in pre-employment screening, working out which   
   individualsmay not be suitable for hiring.   
   "But, right now, I have to emphasize that there are no direct practical   
   applications," she said.   
   Intheir journal article, the authors mention that separate studies ofautistic   
   children - who typically have trouble lying - have showed theconverse pattern   
   of gray matter/white matter ratios.   
   "The factsthat autistic children have difficulty lying and also show   
   reducedprefrontal white matter constitutes the opposite but comp   
   ementarypattern of the results compared to adults with increased   
   prefrontalwhite matter who find it easy to lie," the    
   researchers wrote.   
   "Althoughautism is a complex condition and cannot be taken as a model for   
   lying,these results ... converge with current findings on adult liars   
   insuggesting that the prefrontal cortex is centrally involved in thecapacity   
   to lie."   
   ###   
   The other researchers were SusanBihrle and Lori LaCasse, also of the USC   
   College's psychologydepartment, Patrick Colletti of the Keck School of   
   Medicine of USC'sdepartment of radiology and Todd Lencz of Hillside   
   Hospital'sdepartment of research.   
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