'Brain fingerprinting': A critical analysis.

20 Recent efforts by various investigators have been directed at using brain waves in detection of deception. One investigator, Lawrence A. Farwell, left academia about a decade ago and founded his company, Farwell Brain Fingerprinting. (See http:/www.brainwavescience.com/.) This business is actively commercializing a putative deceptionrevealing technology in connection with forensic and related areas. As is stated on its Web site, “Farwell Brain Fingerprinting is a revolutionary new technology for solving crimes, with a record of 100% accuracy in research with U.S. government agencies and other applications. . . . The technology is fully developed and available for application in the field.” The present review undertakes a careful analysis of these claims and their background with reference to the one refereed publication in a major psychophysiology journal which Farwell coauthored (Farwell & Donchin, 1991), the voluminous material on the Web address cited above, Farwell’s U.S. patents, court records, and the work of various other researchers. Prior to this analysis, the present review briefly discusses the P300 event-related brain potential, which is the key element of most of the published brain-wave-based deception research. The “Guilty Knowledge Test,” or GKT, which in a form modified for P300 methods yielded the P300 protocol for detecting concealed, crime-related information, is also reviewed, followed by a review of the P300-based deception-detection literature. The issue of P300-based tests’ reported accuracies is also considered. Since Farwell claims that his method is based on a brain-activity index, the “MERMER,” which goes beyond P300, an attempt is also made to analyze this variable, based, of necessity, solely on U.S. patent material. The review then closely examines Farwell’s recently promoted retrospective application of BF, in which the technology is purportedly utilized to exonerate previously convicted—some long ago—felons. Finally, the review highlights methodological problems associated with BF and related methods, including vulnerability to countermeasures and difficulty with developing adequate and appropriate test material, leading to the concluding impression that the claims on the BF Web site are exaggerated and sometimes misleading. It is documented that, in fact, U.S. government agencies most concerned with detecting deception do not envision use of BF. Finally, prospective users and buyers of this technology are issued the classic caveat emptor.