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    FEBRUARY 10, 2005
 
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Research

MRI lie detector may tell fact from fiction

Faro

Your pants won’t burst into flames, but Scott Faro thinks he can tell when you’re lying. At least, he thinks he’s on the right track.

Faro, a newcomer to the radiology department at the School of Medicine and Temple University Hospital, is the director of Temple’s Functional Brain Imaging Center and Clinical MRI. He and his team presented a new method of lie detection to the Radiological Society of North America’s annual meeting, held recently in Chicago. The world’s largest media outlets, including the BBC, Wall Street Journal and National Public Radio, have reported his findings internationally.

The concept, at least in summary, is straightforward. Using the same functional magnetic resonance imaging (fMRI) scan that picks up brain tumors, Faro and his colleagues found that different areas of the brain were active when a person told the truth as opposed to when they lied.

In addition, more areas of the brain were activated when the person was trying to be deceptive. Although it’s too early to tell how effective the fMRI test is, the hope is that it will be a more accurate way of separating truth from fiction. While polygraph machines are common on detective shows and in courtroom dramas, their accuracy can be called into question.

Conventional lie detectors rely on changes to the body like sweating, blood pressure, heart rate and breathing.

But Faro and his team say the accuracy is limited because people who tell the truth can get bad results if they’re nervous or just don’t like being strapped to a lie detector.

“The problem with the polygraph is it’s a measure of how anxious somebody is,” Faro said. “But lots of people become anxious when they are attached to a polygraph, anyway. That can skew results and is a reason why polygraphs aren’t 100 percent accurate.”

Another knock on traditional polygraphs is that they can be fooled by confident liars who don’t get rattled at the thought of an interrogation. Either way, Faro’s method could eliminate these concerns by not analyzing anxiety, but by watching the brain as it comes up with a response.

“With fMRI, you are looking directly at the brain’s activity,” Faro said. “And lying is cognitively quite hard. Watching brain activity provides a more reliable indicator.”

In his study, Faro asked six of 11 volunteers to fire a toy gun and then lie about whether they had pulled the trigger. The other five were asked to tell the truth about what had happened.

Each of the volunteers was then scanned with fMRI while being asked questions about the incident. A traditional polygraph test was also carried out to compare the accuracy of the two methods.

In all cases, the fMRI accurately distinguished between the volunteers who were telling the truth and those who were lying.

“Our plan is to continue to investigate the potential of fMRI both as a standalone test and as a supplement to the polygraph with the goal of creating the most accurate test for deception,” Faro said.

The only shortfall to this method? The practicality of using a large, expensive fMRI to perform the scans.

“It’s not the sort of thing every police station has in the back,” he said. “But in the future, potentially in high-profile cases and as technology becomes cheaper, it might be something people want to look at.”

- By Jordan Reese

 

 


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