Lie Detection Systems: Part 2

1. Facial Thermography

Facial thermography represents a safe, non-invasive technology that measures skin surface temperature on a real time basis.  Like VSAs, facial thermography has an advantage over polygraph systems in that its non-invasive nature lends itself to covert applications.  Recently, Doctors B. M. Gratt and E. A. Sickles from the University of California at Los Angeles used microwave receivers to measure thermal radiation emitted from a human face and analyze blood flow differences between different regions of the face.  Last year, Doctors Levine, Palvidis, and Cooper refined the concept of facial thermography to explore the fact that specific activities are associated with characteristic, facial thermal signatures.

One 25-person pilot study conducted in 2002 between DoDPI and outside researchers examined the possible utility of a new thermal imaging device that measures the radiant energy emitted from an examinee’s face.  The published report, which focused on thermal imaging as an adjunct or potential alternative to traditional polygraph measurements, claimed that thermal imaging results achieved higher accuracy than the polygraph.  Although according to the 2003 National Research Council report on polygraph testing, the pilot study conducted by DoDPI failed to provide acceptable scientific evidence to support facial thermography as a viable method for detecting  deception.

1.1 Conclusions

Similar to other veracity studies done on emerging lie detection methods, studies based on facial thermography draw conclusions based on small sample sizes, uncontrolled environments, uncooperative subjects, inconsistent judging criteria, and other variables that detract from the scientific basis of which successful results are often cited.  Unless new research can provide acceptable scientific evidence to support facial thermography as a viable alternative to the polygraph, the concept of using thermal imaging as a method for lie detection will likely remain an adjunct to traditional polygraph measurements.

2. Functional Brain Imaging

Functional brain imaging looks at brain function more directly than polygraph testing by using positron emission tomography (PET) and magnetic resonance imaging (MRI), which employ strong magnetic fields to induce brain tissue molecules to emit distinctive radio signals used to monitor blood flow and oxygen consumption in the brain.  Within the context of MRI, the detection of blood-oxygen-level-dependent (BOLD) signals has garnered the name functional magnetic resonance imaging (fMRI).  Research studies are focused on using fMRI to analyze knowledge and emotion characteristics theorized to link deception to physiological brain activity.  In addition, other research areas have focused on combining PET and fMRI with simultaneous measurements of skin conductance response.  Scientists are quick to point out, however, that applied fMRI studies completed thus far have similar limitations to earlier polygraph studies.  Furthermore, they point out that fMRI analysis is expensive, time-consuming (2-3 hours per examine), and highly sensitive to subject motion during the brain scan.  To overcome some of these potential deficiencies for veracity applications, some researchers suggest the use of an electroencephalograph (EEG), which directly measures the electrical output of the brain rather than attempting to map brain activity from blood flow patterns.  One EEG study conducted by Jennifer Vendemia, a researcher from the University of South Carolina, suggests that predictable patterns of energy fluctuating brain activity occur when people lie.  The correlation between brain activities and lying are nothing new, but the fact that researchers continue to explore this path makes the possibility of brain imaging a potential candidate to supplement or eventually replace traditional polygraph techniques.

2.1 Conclusions

Psychology professor John Gabrieli predicts that within ten years research advances in neurotechnology could yield brain scanners in schools and airports.  One Iowa company called Brain Fingerprint Laboratories claims it has developed technology that can identify specific brain wave patterns that people emit when they are looking at or discussing something they have already seen.  Furthermore, psychiatrist Daniel Langleben from the University of Pennsylvania School of Medicine has found that increased activity in several brain regions is visible in an fMRI scan when people lie.  However, Doctor Langleben also contends that lying is a complex behavior and that it is likely to be linked to a large number of unknown brain sites.

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