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Memory and Lie: Brain Fingerprinting

yml's picture

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I was recently introduced with a new technology that might have great effect on our criminal justice system, Brain Fingerprinting. As amazing this new technology is, Brain Fingerprinting has generated much controversy since its introduction and until now. It is claimed that Brain Fingerprinting can tell whether the memory is present or absent in one’s brain with 100% accuracy and used to test suspects of crimes. I am attempting to look at how it works and whether it should be used in criminal justice system. I also will look at how memory plays role in relation with lying.  

            Brain Fingerprinting was developed by Larry Farwell, a founder and president of Brain Fingerprinting Laboratories, Inc, in Iowa. The technology is “based on a sub-set of brain waves that register as brief electrical patterns when a person recognizes family stimuli” [3]. So how it works it, a subject is presented with three types of stimuli: target stimuli, which has details of an activity that would be known to the subject, irrelevant stimuli, which would not be expected to elicit response, and probe stimuli, which would be only known to a select few, like the perpetrator and investigators of a crime. When a stimulus stimulates memories, it causes the brain to fire off an electrical response 300 milliseconds after the stimulus, which is known as the “P300 effect” [3]. So how it is used in criminal justice system is a suspect is shown subject relevant words, phrases, or pictures that would only be known by a perpetrator of the crime. Then the sensors on a headband measure the EEG from several locations. The responses measures here is defined as a MERMER, a memory and encoding related multifaceted electroencephalographic response, which is derived from the EEG data at different sites. So the MERMER response would be present in a suspect who has specific knowledge about the words, phrases, or pictures presented [4], and vice versa for an innocent suspect. 

            There were two criminal cases that made Brain Fingerprinting known to the public and also brought controversies. The first one was Terry Harrington case. He was charged with murder of a retired police captain and given life sentence. Claiming his innocence, he voluntarily took Brain Fingerprinting test and the result showed that he had no memories of the information related to the crime scene, which meant that he was innocent. In 2001, his lawyer sought a new trial on the ground of newly discovered evidence, which includes the result from Brain Fingerprinting [5]. Another case was Jimmie Ray Slaughter case, who was convicted of murdering his girlfriend and their daughter. According to Brain Fingerprinting, he also showed no memory of the crime and his case was brought back to the court [3]. 

            Larry Farwell presented 100% accuracy of the determinations of “information present” or “information absent” over 170 tests with FBI agents. So he claims the system has extreme accuracy [6], which, based on his studies, reasonable claim. Because of its usage, Brain Fingerprinting system is often compared with lie detectors. Farwell argued that Brain Fingerprinting is far more reliable than polygraphs or other lie detector because it simply detects scientifically if specific information is stored in the brain or not [7]. Unlike polygraph testing, Brain Fingerprinting does not require any verbal responses to questions or stimuli, therefore is not affected by any emotion [4].

            On the other hand, many scientists accuse Farwell of making misleading and exaggerated claims. One of his opponents is Dr. Emanuel Donchin, who is Farwell’s former mentor and worked with Farwell on this development. He said that although preliminary investigations seem to be promising, much research is needed before we can use this science outside of a laboratory environment [7]. Another researcher, Dr. John Polich, also agrees that there needs to be more testing, including corroborating research from different labs, before it is ready for commercial application [1]. And from a replicated study with a mock crime scenario done by Dr. John Allen resulted only 50% accuracy in identifying guilty persons [3].

            So, how reliable is this technology? Even more, is this reliable method that could be used in criminal justice system at all?

            Although Brain Fingerprinting is trying to figure out whether someone is lying or not, the core of this system is memory. All it is doing is telling others if the memory is in the subject’s brain or not. But how reliable is memory? Many people think that brain is like a video tape player and when memory is recalled, it is like playing a video tape. But the fact is memories are constantly recreated and reconstructed every time they are retrieved. In that case, can we really trust reconstructed memory to determine any recalled memory to be truth and absence of the memory as proof of not committing such action in the first place? More questions rise in the case of crimes. Sara Solovitch asks in her article, “how does a heightened state of arousal affect the memory process?” If a crime was done in a rage, can the perpetrator remember details of the crime scene that the investigators think would be remembered by the perpetrator only?  How about if the perpetrator was high on drugs or alcohol at the time of the crime? [3]

False negative can appear in Brain Fingerprinting, because a guilty person might pass the test because he no longer remembers the details or because he didn’t notice them in the first place. There is great risk to say the absence of the specific memory means the suspect did not commit the crime, because “we don’t know enough of how memories are formed during crimes” as William Iacono [3] said and we do not really know for sure what the perpetrator remembers or what he does not.

Iacono on the other hand claimed a positive result on the Brain Fingerprinting test is almost always accurate, because then why else the subject has a stored memory of specific event that he/she should not know if was not there [3]. But I disagree with this argument. How about memory that was subliminally stimulated? I admit this could be less relevant in criminal justice situations, but we really cannot and should not rule out any possibilities with criminal acts. So if the memory was created unconsciously, it will say that the memory is stored in his/her brain, even though that person has no recollection of it. What about if a person does not remember because the person repressed it for some reason? Similarly, what about due to retrieval failure, the memory is stored in long term memory, but is not able to retrieve at the moment? These can be applied to innocent witnesses, who saw more than what the investigators assumed witnesses have not seen. When those images or phrases appear in the test, it might show brain waves that show the presence of the memory, but the subjects can really not consciously be aware of that memory.

            Should we really rely on memory to detect lies in people? Brain is much more complicated than we have the knowledge of. I am not sure whether we should tie memory with lying, in which case Brain Fingerprinting is not better than Lie detectors. I admit current lie detectors have some issues with reliability and do not have accuracy result of 100% like Farwell did with Brain Fingerprinting. But I rather have lie detector improved with more technology than relying on Brain Fingerprinting. Memory is just not stable enough to be used in criminal justice system. Maybe, I just do not have enough understanding and/or knowledge of memory, how brain works, and how Brain Fingerprinting, and will have change of mind once I do. But for now, this is where I stand and I think the criminal justice system is with me on this.

            The judges found Brain Fingerprinting to have insufficient scientific documentation to be admitted as evidence and Slaughter was executed by lethal injection on 2005. The Iowa Supreme Court, on the other hand, ruled that the Brain Fingerprinting evidence admissible in court, which shed big light on Brain Fingerprinting technology. Maybe Brain Fingerprinting will be used more widely in few years and play major role in criminal justice system, or maybe it will disappear from the scene in couple of years. I do not know what kind of future holds for this science. But for now, I think there are more questions that need to be answered about memory and brain before it is used to free potential killer back in the street.













Paul Grobstein's picture

lie detection, brain fingerprinting, and ...

Seems to me the concerns you express here are relevant not only to the current wave of fashion but also to the earlier "lie detection" technologies and to anticipated brain imaging technologies.  In all cases, the problem is, as you say, that there can be no assurance that the brain's report of a past event has historical validity.  So, how should we handle efforts to establish the "reality" of past events in forensic contexts?