MRI: The Ultimate Lie Detector?

Nov. 29, 2004 -- Separating a lie from the truth may get easier, thanks to magnetic resonance imaging ( MRI).

Just ask Scott Faro, MD, director of Temple University's Functional Brain Imaging Center and Clinical MRI. Faro and colleagues recently tested brain imaging when test participants were lying.

They recruited 10 volunteers, asking half to shoot a toy gun and lie about it. The nonshooters were told to tell the truth about the situation.

Here's the catch: Participants were questioned about their tales -- false or true -- during brain imaging.

But that's not all. During the brain imaging studies, a polygraph or lie detector test was also done.

If you watch crime movies and TV shows, you've probably seen polygraph tests. They track body functions, such as breathing, blood pressure, and the skin's ability to conduct electricity, which rises when people sweat. Those physical signs can indicate lying.

But the polygraph test isn't perfect. Some smooth talkers can flim-flam their way through it by controlling their body's reactions. Brain imaging might be a more revealing lie detector.

In the study, the images showed that different brain areas worked during lying and truth telling. The liars had three specific brain regions activated that were not active in individuals who told the truth. Those differences could reveal liars.

In the study, brain imaging was equally good at detecting lies as polygraph tests. It's too early to know if brain imaging can be fooled in the same manner as polygraph tests, but Faro hopes to find out.

"We have just begun to understand the potential of MRI [brain imaging] in studying deceptive behavior," he says, in a news release.

Faro's team presented the findings in Chicago at the annual meeting of the Radiological Society of North America.