with 8 of 12 for the polygraph) and equivalent accuracy on deceptive ones (6 of 8 correct). Unfortunately, the published report uses only a subset of the examinees and offers no information on the selection process. It also gives no information on the decision criteria used for judging deceptiveness from the thermographic data.

The DoDPI researchers were interested in the possibility of combining the new information with that from the traditional polygraph channels. This required a new effort at computer scoring, as well as an explicit effort at extracting statistical information from the thermal recordings. The DoDPI report indicates moderately high correspondence with experimental conditions for polygraph testing (an accuracy index [A] of 0.88), relatively low correspondence with thermal signals alone (A of 0.70), and some incremental information when the two sets of information are combined (A of 0.92). Despite the public attention focused on the published version of this study in Nature (Pavlidis, Eberhardt, and Levine, 2002), it remains a flawed and incomplete evaluation based on a small sample, with no cross-validation of measurements and no blind evaluation. It does not provide acceptable scientific evidence to support the use of facial thermography in the detection of deception.

MEASUREMENTS OF BRAIN FUNCTION

The polygraph and other measures of autonomic and somatic activity reflect the peripheral manifestations of very complex cognitive and affective operations that occur when people give deceptive or nondeceptive answers to questions. By their very nature, polygraph measurements provide an extremely limited and indirect view of the complex underlying brain processes. A reasonable hypothesis is that by looking at brain function more directly, it might be possible to understand and ultimately detect deception. This section discusses some brain measurement technologies that are beginning to be explored for their ability to yield techniques for the psychophysiological detection of deception.

Functional Brain Imaging

Over the past 15 years, the field of cognitive neuroscience has grown significantly. Cognitive neuroscience combines the experimental strategies of cognitive psychology with various techniques to actually examine how brain function supports mental activities. Leading this research are two new techniques of functional brain imaging: positron emission tomography (PET) and magnetic resonance imaging (MRI) (see Buxton [2002] and Carson, Daube-Witherspoon, and Herscovitch [1997] for comprehensive general reviews). Over the past 5 years, these techniques have



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