Q+A CENTER

One essential assumption underpins this entire discipline: the brain being studied is "normal." But, what happens if brain anatomy or physiology is anomalous?

Dr. Adrian Raine and Yaling Yang of the University of Southern California (Los Angeles) and their colleagues determined that individuals who habitually lie and cheat have less gray matter and more white matter than average in their prefrontal cortex. Because gray matter consists of brain cells while white matter forms the "wiring" or intercellular connections, pathological liars may have a greater capacity to fib and fewer moral restraints. From a group of initial volunteers, using psychological tests and interviews, investigators identified 12 pathological liars, 16 persons with antisocial personality disorder but no history of lying and 21 normal subjects. All participants underwent brain MRIs.

Liars showed 22 to 26 percent increase in prefrontal white matter and a 36 to 42 percent reduction in prefrontal grey/white ratios compared with both antisocial and normal controls.

The outcome confirms evidence of a structural brain deficit in habitual liars—implicating the prefrontal cortex as an important (but not exclusive) component in the neural circuitry behind dishonesty—and posits a neurobiological correlate for the deceitful persona. Those are encouraging findings from which to explore the relationship between lying and white matter. For example, brain scans of autistic people, who lie with difficulty, depict the converse; less white matter than usual.

The U.S. Intelligence Community reportedly has approached two premier neuroscience research facilities (the Center for the Study of Brain, Mind and Behavior at Princeton University and Harvard University's Social Neuroscience and Psychopathology Laboratory) with offers to support development of a "post-9/11 lie detector." Accordingly, any new solution likely would be multimodality in design, combining several technologies to sense minute changes in body position, facial expression and neuron-level activation in the prefrontal cortex and associated gyri.