Liars’ brains make fibbing come naturally
12:09 30 September 2005
NewScientist.com news service
Celeste Biever

British Journal of Psychiatry
The brains of pathological liars have structural abnormalities that
could make fibbing come naturally.

“Some people have an edge up on others in their ability to tell lies,”
says Adrian Raine, a psychologist at the University of Southern California
in Los Angeles. “They are better wired for the complex computations involved
in sophisticated lies.”

He found that pathological liars have on average more white matter in
their prefrontal cortex, the area of the brain that is active during lying,
and less grey matter than people who are not serial fibbers. White matter
enables quick, complex thinking while grey matter mediates inhibitions.

Raine says the combination of extra white matter and less grey matter
could be giving people exactly the right mix of traits to make them into good
liars. These are the first biological differences to be discovered
between pathological liars and the general population.

Systematic manipulation
Other researchers have used brain imaging to show that the prefrontal
cortex is more active when ordinary people tell lies. They are looking for
ways to use this as an alternative to the polygraph test.

But pathological liars are a distinct group who systematically
manipulate others, lie or use aliases for financial gain or personal pleasure,
such as to get sickness benefits or to skip work. “It’s almost like a
livelihood,” says Raine.

Until now no one has looked at the structure of the brains of this
particular group, says psychologist Maureen O’Sullivan of the
University of San Francisco in California, who specialises in lying and truthfulness.

Raine interviewed 108 volunteers from five temporary employment
agencies in Los Angeles and set them standard psychopathic tests. This allowed him
to identify 12 as pathological liars, 16 as people with a personality
disorder but who did not exhibit pathological lying and 21 as controls, who were
neither anti-social, nor liars.

White matter
Using magnetic resonance imaging (MRI), he scanned the brains of all
three groups and found that liars had 26% more white matter compared with
anti-social, non-liars, and 22% more than the controls. Liars also had
14% less grey matter than the controls.

Responsible for information transmission, white matter is composed of
nerve fibres or “axons” that connect nerve cells or neurons to each other.
Raine believes that having more white matter makes people better at the
complex process of lying, which involves manipulation, thinking ahead and
multi-tasking.

“It’s a bit like being a mind reader. You have to think, ‘what does she
know about the situation, what does she not know’,” he says. You also have
to suppress anxious emotions and the automatic impulse to tell the truth.
Austistic children, who find it very difficult to lie, develop white
matter at a sixth the rate of ordinary children.

Grey matter mostly comprises the cell bodies of neurons, which process
information. Previous studies have shown that people with less grey
matter tend to break more rules and care less about moral transgressions, says
Raine.

Simple lies
“This is a very interesting study,” says O’Sullivan. But she warns that
more data is needed. “We don’t know whether they are good liars, all we know
is they lie a lot,” she explains.

Psychologist Bella DePaulo at the University of California, Santa
Barbara, who studies deception, also found the study “intriguing” but points out
that not all lies are more complex than truths, nor do they necessarily
require more inhibition.

“People who know that their fabricated stories may be challenged will
sometimes practise telling their false tales. After a while, the
made-up story may come to mind more readily than the true one,” she says.

British Journal of Psychiatry (October 2005)