Brain fingerprinting
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"Brain Fingerprinting" is a controversial proposed investigative technique that measures recognition of familiar stimuli by measuring electrical brain wave responses to words, phrases, or pictures that are presented on a computer screen. Brain fingerprinting was invented by Lawrence Farwell. The theory is that the suspect's reaction to the details of an event or activity will reflect if the suspect had prior knowledge of the event or activity. This test uses what Farwell calls the MERMER ("Memory and Encoding Related Multifaceted Electroencephalographic Response") response to detect familiarity reaction. One of the applications is lie detection.
Despite claims of high accuracy, Farwell's "brain fingerprinting" technique has been criticized on a number of fronts [1] most notably in a number of papers by J. Peter Rosenfeld of Northwestern University. [2] Contrary to research by Farwell and others suggesting that brain fingerprinting has a 100% accuracy rate, research by Rosenfeld and others has suggested that, in the presence of learned countermeasures, the wider class of P300-based tests, which includes the brain fingerprinting technique may give results close to those obtained by chance.[3]
A report by the United States General Accounting Office in 2001 reported that the three scientists it interviewed (including Professor Rosenfeld) had expressed a need for more research to demonstrate Brain Fingerprinting's application as an investigative tool. [4]
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[edit] Technique
The person to be tested wears a special headband with electronic sensors that measure the EEG from several locations on the scalp. In order to calibrate the brain fingerprinting system, the testee is presented with a series of irrelevant stimuli, words, and pictures, and a series of relevant stimuli, words, and pictures. The test subject's brain response to these two different types of stimuli allow the testor to determine if the measured brain responses to test stimuli, called probes, are more similar to the relevant or irrelevant responses.[citation needed]
The technique uses the well known fact that an electrical signal known as P300 is emitted from an individual's brain approximately 300 milliseconds after it is confronted with a stimulus of special significance, e.g. a rare vs. a common stimuls or a stimulas the proband is asked to count.[citation needed] The novel interpretation in brain fingerprinting is to look for P300 as response to stimuli related to the crime in question e.g., a murder weapon or a victim's face.[citation needed] Because it is based on EEG signals, the system does not require the testee to issue verbal responses to questions or stimuli.
Brain fingerprinting uses cognitive brain responses, brain fingerprinting does not depend on the emotions of the subject, nor is it affected by emotional responses.[citation needed] Brain fingerprinting is fundamentally different from the polygraph (lie-detector), which measures emotion-based physiological signals such as heart rate, sweating, and blood pressure.[citation needed] Also, unlike polygraph testing, it does not attempt to determine whether or not the subject is lying or telling the truth. Rather, it measures the subject’s brain response to relevant words, phrases, or pictures to detect whether or not the relevant information is stored in the subject’s brain.[citation needed]
[edit] Background and terminology
"Brain fingerprinting" is a computer-based test that is designed to discover, document, and provide evidence of guilty knowledge regarding crimes , and identify members of dormant terrorist cells. It has also been used to evaluate brain functioning as a means of early detection of Alzheimer’s and other cognitively degenerative diseases, and to evaluate the effectiveness of advertising by measuring brain responses.
This is primarily a discussion of the Dr. Larry Farwell's paper, “Using Brain MERMER Testing to Detect Concealed Knowledge Despite Efforts to Conceal” [1], published in the Journal of Forensic Sciences in 2001 by Dr. Farwell and FBI Supervisory Special Agent Sharon Smith of the FBI.
This paper describes a test of brain fingerprinting, a technology based on EEG that is purported to be able to detect the existence of prior knowledge or memory in the brain. The P300 occurs when the tested subject is presented with a rarely occurring stimulus that they feel is significant.[citation needed] When an irrelevant stimulus is presented, a P300 is not expected to occur.[citation needed] The P300 is widely known in the scientific community, and is also known as an Oddball-evoked P300.[citation needed] A similar response occurs in as an N400 during syntactic or semantic processing and is elicited by inappropriate words or strange grammar structures.[citation needed]
While researching the P300, the author of this paper, Dr. Farwell, created a more detailed test that not only included the P300, but also observes the stimulus response up to 800ms after the stimulus. He calls this technique a MERMER, memory and encoding related multifaceted electroencephalographic response. This P300, an electrically positive component, maximal at the midline parietal area of the head, has a peak latency of approximately 300 to 800 ms. The MERMER includes the P300 and also includes an electrically negative component, maximal at the midline frontal area, with an onset latency of approximately 800-1200ms.[citation needed]
[edit] Current uses and research
Dr. Farwell has tentatively explored the use of this technology as a routine test for several forms of employment, especially in dealing with sensitive military and foreign intelligence screening.[citation needed] With clearly defined probes based on valid intelligence, it might be possible to determine if an applicant for employment had ever been trained in espionage or as a terrorist.[citation needed] Such screening procedures might potentially be much more effective than polygraph screening, which to this date, has never been shown to have prevented an act of espionage.[citation needed] Research into brain fingerprinting has also been funded by the CIA.[citation needed] One such study showed that several different types of stimuli could be used to determine whether a subject was “information present” or “information absent” with respect to several different kinds of information.[citation needed] A group of subjects enacted a simulated espionage and were then subjected to relevant stimuli in the form of pictorial probes. Another set of stimuli were presented to naval medical personnel in the form of phrases and acronyms that would only be known to a military medical professional. A third set of stimuli were presented to individuals who had actually been involved in crimes by way of verbal probes. In each case, brain fingerprinting correctly identified those individuals who were “information present” and “information absent” in each group, thus, showing its validity across several different types of stimuli and in a variety of different situations involving different types of information stored in the brain.[citation needed]
Brain Fingerprinting has also, from its conception, been a medical tool which can be used to detect symptoms of Alzheimer's disease and other forms of dementia before many of the more degenerative effects have set in. With early diagnosis, the progression of Alzheimer's symptoms can often be delayed through the use of medications and through dietary and lifestyle changes.[citation needed]
In a study with the FBI, Dr. Farwell used brain fingerprinting to show that test subjects from specific groups could be identified by their relation to specific knowledge which would only be known to members of those groups.[citation needed] A group of 17 FBI agents and 4 non-agents were exposed to stimuli (words, phrases, and acronyms) that were flashed on a computer screen. The probe stimuli contained information that would be common knowledge only to someone within federal law enforcement. With 100% accuracy, brain fingerprinting identified the agents from the non-agents. A further study was able to differentiate between individuals who had participated in real life events and those who had not.[citation needed] This research has been documented in the Journal of Forensic Sciences.
[edit] Use in criminal investigation
Farwell's MERMER has been ruled admissible as evidence in court in the reversal of the murder conviction of Terry Harrington.[citation needed] Following a hearing on post-conviction relief on November 14, 2000, an Iowa District Court held that Dr. Farwell’s Brain Fingerprinting P-300 test results were admissible as scientific evidence as defined in Congress Ruling 702 and in Daubert v. Merrell Dow Pharmaceutical. Harrington was freed by the Iowa Supreme Court on constitutional grounds.
Brain Fingerprinting testing was also “instrumental in obtaining a confession and guilty plea” from serial killer James B. Grinder, according to Sheriff Robert Dawson of Macon County, Missouri. In August 1999 Dr. Farwell conducted a Brain Fingerprinting test on Grinder, showing that information stored in his brain matched the details of an, until then, unsolved murder.[citation needed] Grinder pled guilty to the rape and murder of Julie Helton in exchange for a life sentence without parole. He is currently serving that sentence and has since confessed to the murders of three other women.
[edit] See also
- Guilty Knowledge Test
- Concealed Information Test
[edit] References
- ^ American Observer: Brain Fingerprinting Skepticism. By Carolyn Fox
- ^ J. Peter Rosenfeld. "Brain Fingerprinting:" A Critical Analysis
- ^ J. Peter Rosenfeld. Simple, Effective Countermeasures to P300-based Tests of Detection of Concealed Information (PDF)
- ^ United States General Accounting Office Report to the Honorable Charles E. Grassley, U.S. Senate. INVESTIGATIVE TECHNIQUES: Federal Agency Views on the Potential Application of "Brain Fingerprinting" October 2001
