CHICAGO – When people lie, they use different parts of their brains than when they tell the truth, and these brain changes can be measured by functional magnetic resonance imaging (fMRI), according to a study presented today at the annual meeting of the Radiological Society of North America. The results suggest that fMRI may one day prove a more accurate lie detector than the polygraph.
"There may be unique areas in the brain involved in deception that can be measured with fMRI," said lead author Scott H. Faro, M.D. "We were able to create consistent and robust brain activation related to a real-life deception process." Dr. Faro is professor and vice-chairman of radiology and director of the Functional Brain Imaging Center and Clinical MRI at Temple University School of Medicine in Philadelphia.
The researchers created a relevant situation for 11 normal volunteers. Six of the volunteers were asked to shoot a toy gun with blank bullets and then to lie about their participation. The non-shooters were asked to tell the truth about the situation. The researchers examined the individuals with fMRI, while simultaneously administering a polygraph exam. The polygraph measured three physiologic responses: respiration, blood pressure and galvanic skin conductance, or the skin's ability to conduct electricity, which increases when an individual perspires.
The volunteers were asked questions that pertained to the situation, along with unrelated control questions. In all cases, the polygraph and fMRI accurately distinguished truthful responses from deceptive ones. fMRI showed activation in several areas of the brain during the deception process. These areas were located in the frontal (medial inferior and pre-central), temporal (hippocampus and middle temporal), and limbic (anterior and posterior cingulate) lobes. During a truthful response, the fMRI showed activation in the frontal lobe (inferior and medial), temporal lobe (inferior) and cingulate gyrus.
Overall, there were regional differences in activation between deceptive and truthful conditions. Furthermore, there were more areas of the brain activated during the deception process compared to the truth-telling condition.
Dr. Faro's study is the first to use polygraph correlation and a modified version of positive control questioning techniques in conjunction with fMRI. It is also the first to involve a real-life stimulus. "I believe this is a vital approach to understand this very complex type of cognitive behavior," Dr. Faro said. "The real-life stimulus is critical if this technique is to be developed into a practical test of deception."
Because physiologic responses can vary among individuals and, in some cases, can be regulated, the polygraph is not considered a wholly reliable means of lie detection. According to Dr. Faro, it is too early to tell if fMRI can be "fooled" in the same manner.
However, these results are promising in that they suggest a consistency in brain patterns that might be beyond conscious control.
"We have just begun to understand the potential of fMRI in studying deceptive behavior," Dr. Faro said. "We plan to investigate the potential of fMRI both as a stand-alone test and as a supplement to the polygraph with the goal of creating the most accurate test for deception."
Dr. Faro's co-authors on this paper were Feroze Mohamed, Ph.D., Nathan Gordon, M.S., Steve Platek, Ph.D, Mike Williams, Ph.D., and Harris Ahmad, M.D.
Will fMRI stand alone as a test for deception? Dr. Faro admits he's not yet sure: "The polygraph looks at only peripheral stimulus as the end result of a long chain of primary central areas of activation of the brain. We're now getting to the origin of the activation."
Dr. Faro called the results "promising" and said he hopes to gain the interest of major organizations such as the Department of Homeland Security, the National Security Administration or the CIA to help fund further research and larger group studies using the same methods, but he says the technology is expensive.
"It's probably going to be used on the academic side to understand psycho-social behavior, and on the criminal side, it's going to be used for major criminals," said Dr. Faro. "We're looking at areas of tremendous concern with terrorism, where the expense is minimal compared to the potential disaster. Looking at industrial or business-related crimes, certainly Martha Stewart could afford this test if she was truly interested."
Imagine people negotiating a huge business deal demonstrating their sincerity by agreeing to a brain scan while being asked questions about whether they intend to go through with a deal in good faith. Questions about each of the commitments in the contract could be asked. Will that give an advantage to superficial people who are sincere but prone to changing their minds? How much do intentions matter?
Update: One thought: If one dreams up a lie well ahead of time (like days or weeks) will its recall look more like a truth on a brain scan? If one can fantasize the lie and make it into something like a real memory it might require less mental effort to recall and/or construct than a lie made up on the spot. Therefore in a brain scan it might look more like a regular memory.
|Share |||Randall Parker, 2004 December 01 12:48 AM Brain Surveillance|