Brain Wave Scanners

Brain Wave Scanners

The term brain wave scanners, in the context of law enforcement, encompasses an array of research studies and technological developments undertaken with the aim of using electronic equipment to determine the truth or falsity of an individual's statements. While such a concept may sound farfetched at first glance, it is based not on subjective phenomena, but on apparently measurable brain states. Using magnetic resonance imaging (MRI) and related equipment, it is possible to measure a subject's brain for increased activity that may indicate the telling of a lie.

The concept of a brain wave scanner is not unlike that of a polygraph, but whereas a polygraph measures fluctuations in heart rate and breathing, a scanner measures brain responses to stimuli. It could be more effective, because a "good liar" may experience little excitement in the circulatory system; however, even such an individual would be required to expend extra energy on the thought necessary to tell a lie, and it is this energy that a brain wave scanner may be able to measure.

It is often said that the truth is much easier to remember than a lie, and the activity measured by brain wave scanners offers a concrete illustration of this. When one is asked a question to which one knows the true answer, that answer comes first to mind automatically. Even if the individual has already prepared and rehearsed a lie, it is still necessary to think past the true answer and access the lie. This extra activity is easily measured on a brain scan.

Testing and Possible Applications

In a 2001 University of Pennsylvania experiment using MRI, 18 subjects were given objects to hide in their pockets, then shown a series of pictures and asked to deny that the object depicted was in their pockets. Included was a picture of the object they had pocketed, meaning that the subject was lying when saying that the object was not in his or her pocket. At that juncture, the MRI recorded an increase of activity in the anterior cinglate, a portion of the brain associated with inhibition of responses and monitoring of errors, as well as the right superior frontal gyrus, which is involved in the process of paying attention to particular stimuli.

After the September 11, 2001, terrorist attacks, a number of government agencies began to take a new look at brain scanning technology as a means of security screening. In 2002, officials of the National Aeronautics and Space Administration reportedly informed airline officials that they were developing brain-monitoring technology for use in screening airline passengers. Such activity, along with an increase of interest in brain-wave scanning by the Federal Bureau of Investigation, has raised concerns among civil-liberties groups, which view brain-wave scanning as a particularly objectionable invasion of privacy in the service of public security.



Feder, Barnaby J. "Truth and Justice, By the Blip of a Brainwave." New York Times. (October 9, 2001): F3.

Vedantam, Shankar. "The Polygraph Test Meets Its Match." Washington Post. (November 12, 2001): A2.

Wright, Karen. "Go Ahead, Try to Lie." Discover. 22, no. 7 (July 2001): 21–22.

Young, Emma. "Brain Scans Can Reveal Liars." New Scientist. (November 12, 2001).


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