These are used "in the form of words, pictures, or sounds..." which a computer presents for a second or even a partial second. Incoming stimulus, if it is worth noting, results in a P-300, which is an electrical brain response. The P-300 is part of a MERMER or a memory and encoding related multifaceted electroencephalographic response, which is a larger brain response.
Originally event related potentials (ERP) was the method used for studying brain activity information processing. The limitation of the ERP is that it causes elimination of all patterns that are complex and results in the meaningful signals also being lost. The multifaceted electroencephalographic response analysis or MERA was developed due to the limitation of the ERP. Farwell found that incorporation of this technique resulted in the elicitation of MERMER when the individual being tested recognized a stimulus that was incoming. While fMRI is still in new stages and science recommends expansion in research for validity in results from an established base for which to compare and to corroborate pattern prediction in truth telling and deception the legal area however, are able to use the results of brain fingerprinting as evidence in reaching guilty or not guilty verdicts in court cases. Brain fingerprinting gained a legal victory in the case of Terry Harington who was acquitted because "Brain Fingerprinting patterns did not match with the crime scene evidence." (Bansal, Singh, Sreenivas, Pandey, 2004)
The work of Dr. Farwell has investigated the scientific validity of 'brain fingerprinting' and the P300 electrical brain wave response is stated to be "widely known and accepted in the scientific community and there have been hundreds of studies conducted and articles published on it over the past thirty years." (Interview with Dr. Farwell, nd) Dr. Farwell claims an accuracy rate of 100% for brain fingerprinting tests stating that in 200 test total there "have been no false positives or false negatives in instances where a determination of 'information present' or 'information absent' was made." (Taylor, 2007)
Criticisms of brain fingerprinting testing are those stated as follows:
The mental capacity of individuals to retain information during the crime or prior to the test (examples: intoxication, drugs, under stress influences);
How memories are formed during crimes is not understood;
Individuals could attempt to deceive the brain fingerprinting test;
Bias could easily find its way into the test and the test results through the decision process exercised by the test administrator in selecting the specific stimuli;
Brain fingerprinting raises questions relating to civil liberties;
According to Dr. Farwell in response to these questions of critics in the case of the second question, the brain is always recording information whether the individual is aware of the fact or not. Furthermore, Dr. Farwell relates that in one case the subject "was on alcohol and drugs, and in a highly emotionally-charged states at the time of the murder [the victim in that case]..." And the results were still "excellent." 57 in relation to attempted to deceive the brain fingerprinting test, since the brain fingerprinting is not a determination of truth or falsehood and instead "for the presence of certain information in their brain...BF cannot be 'beaten' or 'fooled by relaxed well-prepared criminals." (Taylor, 2007) Stated is that: "Because the BF test is objective and measures a brain response at the moment of recognition, it is equally effective when given to a normal mentally stable individual as it is when given to a sociopath, hardened criminal or pathological liar." (Taylor, 2007) in response to critics on the basis of civil liberties, Dr. Farwell states that that brain fingerprinting: "serves the cause of human rights by giving an innocent individual the means to scientifically prove his or her innocence...[it would be a] "...human rights violation to deny access to testing to anyone who is accused of a crime." (Taylor, 2007)
The work of Davachi, Mitchell, and Wagner (2003) entitled: "Multiple Route to Memory: Distinct Medial Temporal Lobe Processes Build Item and Source Memories" state that in the function of memory in the brain "a central function of memory is to permit an organism to distinguish between stimuli that have been previously encountered and those that are novel." These authors conducted a study using "event-related functional MRI to examine the relation between activation in distinct medial temporal lobe subregions during memory formation and the ability (1) to later recognize an item as previously encountered (item recognition) and (2) to later recollect specific contextual details about the prior encounter (source recollection)." The following illustration shows the encoding conditions performed during fMRI scanning.
Encoding conditions performed during fMRI scanning
Source: (Davachi, Mitchell, and Wagner, 2003)
The Washington Post reports that: "The Siemens Magnetom Trio at the University of Pennsylvania is a 10-foot-tall, 14-ton "functional magnetic resonance imaging" fMRI machine. This machine is believed to be the "most formidable lie detector ever built." (2006)
II. Legal and Ethical Implications
Neuroscientific techniques used specifically for identification of deception is an area of technology that is increasingly becoming more sophisticated. There is great hope that that brain scanners will be able to make accurate determinations when an individual is being willfully deceptive. The problem is that brain scans when conducted against the individual wishes are done so in violation of the Fifth amendments protections against self-incrimination. These issues were addressed by the U.S. Supreme Court in U.S. v. Scheffer (U.S. v. Scheffer 523 U.S. 303 (1998) which was a case "in which use of polygraph-based lie detection was barred in court-martial proceedings (most states, but not all also bar or restrict use of polygraph evidence in court proceedings)." In the case of Scheffer, the Supreme Court upheld a bar on introducing polygraph evidence stating that barring this was constitution. In the case of Scheffer, the defendant wanted to introduce polygraph evidence for the purpose of his defense.
The work of Greeley (2004) makes a review pertaining to legal issues relating that there are cases that ethical models for brain imaging might possibly diverge from genetics. The work of Raine et al. (1994) showed that in the brains of committed murders, there is poor functioning in the prefrontal cortex of the brain, which is responsible for controlling impulses. These PET (MRIs) have been used for making the argument of a defendant being predisposed through biological factors to commission of crimes and that the defendant should, for that reason, not be sentenced to death. Failure to produce brain scans resulted in reversal of a conviction of homicide in the case People v. Jones. (Illes and Racine, 2006) it is critical that "models for minimizing harm that may results from false positive and inappropriate attributions of cause-and-effect to otherwise correlative results are critical. Apart from genetic testing, brain maps can be readily portrayed as iconic proof of pathology to people at any level of literacy." (Illes and Racine, 2006) Imaging the brain required specialized medical equipment as well as "the array of parameters used to elicit activations and the statistical thresholds set to draw out meaningful patterns...[as well as] "...the expertise required fro the objective interpretation of the maps themselves." (Illes and Racine, 2006) Finally, the fact that there are no existing standards of laboratory practice since "innovation and creativity still define the state-of-the-art in neuroimaging today" as well as "medicolegal setting" which makes the process even more complex makes it very difficult to draw conclusions relating to "...behavior, responsibility and cognitive well-being." (Illes and Racine, 2006)
Scientists have cautioned concerning ethical issues relating to neuroimaging, which affirms the need for establishing ethical approaches in this area. The work of Winslade and Rockwell (2002) states: "Humans are forever prone to make premature and presumptuous claims of new knowledge.... One may think that brain imagery will reveal mysteries of the human mind. But it may only help us gradually comprehend the organic, chemical and physiological features of the brain rather than provide the keys to unlock the secrets of human behavior and motivation." (Illes and Racine, 2006) Cultural issues must also be considered in that different meanings attached to different 'things' or 'beliefs' within a culture might be dramatically different than the meanings attached to the same word in another culture thereby rendering neuroimaging inept if these cultural issues are not addressed. The specific problem that exists is in the area of interpretation, which is influenced by cultural and religious perspectives that are greatly differential from one societal element to another. The work of Illes and Racine (2006) states as follows:
With the existence of many views about mind and brain, neuroethics will have to foster discussions among neuroscientists whose methods may vary and interpretation of results differ. These discussions will have extend to include meaningful dialogue with scholars in the humanities about concepts like morality, moral judgments and moral emotions -- concepts in need of critical…