There's been a lot of attention the last couple years to the possibility of brain-based lie detector tests -- most of it premature. That coverage, I see now, has overlooked (as did I!) a 2005 study that showed compulsive liars are wired differently -- in an unexpected way -- than the rest of us. NPR's Radio Lab covered it this morning. You can get both the text and the audio at NPR: Radio Lab: Into the Brain of a Liar.
Here's the opening:
The compulsive liars had, in fact, 22-26% more white matter in their prefrontal cortex than did normal controls. The study's author is quoted as saying that allows them (or responds to a need) to "jump from one idea to another and ... come up with more random stories and ideas." I would wonder if the extra-robust prefrontal cortex (the 'thinking' part of our brain, and also a part crucial to negotiating the social world) is needed to run the complex calculations about others' receptions of his lies that a liar needs to do in order to fib successfully.
Morning Edition, March 6, 2008 ·
We all lie — once a day or so, according to most studies. But usually we tell little lies, like "your new haircut looks great!" And most of us can control when we lie or what we lie about. But some people lie repeatedly and compulsively, about things both big and small.In 2005, a study published in The British Journal of Psychiatry provided the first evidence of structural differences in the brains of people with a history of persistent lying. The study was led by Yaling Yang, a doctoral student in psychology at the University of Southern California, and Adrian Raine, an expert on antisocial disorders who is now at University of Pennsylvania.They expected to see some kind of deficit in the brains of these liars, Yang says. But surprisingly, the liars in their study actually had a surplus — specifically, they had more connections in the part of their brains responsible for complex thinking.
Hat tip to Jonah Lehrer at Frontal Cortex for spotting this first.