- Published: November 30, 1999
One hot topic in the field of neuroscience today is the use of neuroscience-based lie-detectors. One such mechanism uses an EEG (electroencephalographic) basis and it’s commonly known as brain fingerprinting. This process, patented by L.A. Farwell, introduces an EEG electrode that, when placed over the parietal cortex, will exert a measurable negative voltage potential when a person sees or hears a familiar stimulus. The magnitude of the negative voltage potential, known as a P300 wave, is inversely proportional to the familiarity of the subject with the presented stimulus. In laboratory testing, this technique has been proven to be more reliable than polygraph-based testing in detecting a person who is willfully telling a lie.
Procedures like brain fingerprinting are now being viewed by neuroscientists as well as lawyers, judges, and policy makers as possible methods of court-admissible lie-detection. The current, polygraph-based, method is barred in most courts in the United States. Questions have arisen about a defendant’s 5th Amendment rights, due to the idea that, when a defendant takes part in a lie-detector test, he essentially becomes a witness against himself. I don’t see how we will ever make a lie-detector that will be admissible in court. The defendant would have to want to participate in the analysis; otherwise his 5th Amendment rights would be violated. We also could not say that a defendant who says he does not trust the test enough to participate in it is guilty by default. Only those who are not guilty would want to take the test, but there is no way to force guilty defendants to participate.Brent Garland and Paul W Glimcher. Cognitive Neuroscience and the Law. Current Opinion in Neurobiology 2006, 16:130–134