Researchers at the University of Pennsylvania School of Medicine have found that telling a lie and telling the truth require different activities in the human brain. The findings will be presented Tuesday, Nov. 13, at the national meeting of the Society for Neuroscience in San Diego, CA. By identifying the brain activity associated with deception and denial, the work paves the way for improvements in lie-detection techniques.
It may also contribute to the field of psychotherapy by advancing understanding of what happens to the brain during the those psychological processes, said Daniel Langleben, MD, leader of the study and assistant professor in Penn's Department of Psychiatry.
In the study, Landgleben and his colleagues used functional magnetic resonance imaging (fMRI) to track brain activity in 18 volunteers who were subjected to an interrogation method known as the Guilty Knowledge Test.
The volunteers were provided with an envelope containing the five-of-clubs playing card and told to hide it in their pockets without divulging what card they held. They were then placed within an MRI scanner and "interrogated" by a computer that showed them a series of playing cards accompanied by the question, "Do you have this card?" The volunteers were directed to denying they held the five-of-clubs when a picture of it came up.
"Sections of the brain that exercises a significant role in how humans pay attention, and monitor and control errors (the anterior cingulate gyrus and parts of the prefrontal and premotor cortex), were, on average, more active in the volunteers when they were lying than when they were telling the truth," Langleben said. "If truth was the brain's normal 'default' response, then lying would require increased brain activity in the regions involved in inhibition and control.
"The results indicated that since fMRI is a more direct measure of brain activity than the method currently used in lie detection (the polygraph) it may have advantages over this technique," he said.
Langleben said he believes the research should be expanded to incorporate larger numbers of individuals from various language and demographic groups, in order to establish a broad base for comparisons.
He believes such studies could lead to new methods in lie detection, one of which might rely on fMRI results "as a 'gold standard' to validate findings of truth or falsehood based on other methods." He will discuss the findings on Sunday at a society-sponsored press conference that will feature the recent fMRI work of four internationally recognized research teams.
