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Brain fingerprinting is a forensic science technique that uses electroencephalography (EEG) to determine whether specific information is stored in a subject's brain. It consists of measuring and recording a subject's electrical brainwaves and brain response known as P300-MERMER ("Memory and Encoding Related Multifaceted Electroencephalographic Response") after the subject is exposed to words, phrases, or pictures on a computer screen. (Encyclopedia of Forensic Science 2014, Farwell & Smith 2001, Farwell, Richardson, and Richardson 2013).
Brain fingerprinting was invented by Lawrence Farwell. He hypothesized that the brain processes known or relevant information differently than unknown or irrelevant information (Farwell & Donchin 1991). The brain's processing of information known to the subject is revealed by a specific pattern in the EEG (electroencephalograph) (Farwell & Smith 2001, Farwell 1994). Farwell's brain fingerprinting originally used the P300 brain response to detect the recognition of the known information (Farwell & Donchin 1986, 1991, Farwell 1995a). Later, Farwell discovered the P300-MERMER, which extends the basic P300 and is reported to provide greater accuracy and statistical confidence (Encyclopedia of Forensic Science 2014, Farwell & Smith 2001, Farwell 1994, Farwell 1995b, Farwell et al. 2013). Brain fingerprinting has an error rate of less than 1%, as well as high statistical confidence (Encyclopedia of Forensic Science 2014) in laboratory research (Farwell & Donchin 1991) and real-life field applications (Farwell & Smith 2001, Farwell et al. 2013). In independent research, William Iacono and others who followed identical or similar scientific protocols to Farwell's have also reported a low error rate and high statistical confidence for brain fingerprinting (e.g., Allen & Iacono 1997, Iacono 2008).
Brain fingerprinting has been ruled admissible for court use in the United States of America (Harrington v. State 2001, Encyclopedia of Forensic Science 2014, Farwell & Makeig 2005, Farwell 2012). It has been used in a number of high-profile criminal cases such as the murder trial of Terry Harrington (Harrington v. State 2001) and the sentencing of serial killer J. B. Grinder (Encyclopedia of Forensic Science 2014, Farwell et al. 2013).
Brain fingerprinting is premised on the fact that an electrical signal known as P300 is emitted from an individual's brain approximately 300 milliseconds after he or she is confronted with a stimulus of special significance, e.g., a rare vs. a common stimulus or a stimulus the subject is asked to count (see P300, Gaillard and Ritter 1983, and Picton 1988 for a comprehensive discussion of this effect). In forensics, P300 is used to detect stimuli related to a crime or other investigated situation, e.g., a murder weapon, victim's face, or knowledge of the internal workings of a terrorist cell (Encyclopedia of Forensic Science 2014, Farwell 1992a, Farwell & Donchin 1991, Harrington v. State 2001, Farwell 2012, Farwell et al. 2013). Because stimulus is sufficient to elicit a P300 response, brain fingerprinting does not require the subject to issue verbal responses to questions or stimuli.
The test subject wears a special headband with electronic sensors that measure his or her EEG from several locations on the scalp, then is exposed to stimuli in the form of form words, phrases, or pictures presented on a computer screen. There are three types of stimuli presented to the subject:
1) "irrelevant" stimuli that are irrelevant to the investigated situation and to the test subject,
2) "target" stimuli that are relevant to the investigated situation and are known to the subject, and
3) "probe" stimuli that are relevant to the investigated situation and that the subject denies knowing.
Probe stimuli contain information that was present at the crime and is thus known only to the perpetrator, investigators, and eyewitnesses. Before the test, the technician identifies the targets to the subject and verifies their familiarity with these stimuli. The scientist also ensures that the subject is not for any reason familiar with irrelevant stimuli and that the subject denies familiarity with the probe stimuli. The significance of the probes is revealed to the subject (e.g., "You will see several items, one of which is the murder weapon"), but he or she is not told which items are probes and which are irrelevant (Encyclopedia of Forensic Science 2014, Farwell 1994, Farwell 2012, Farwell et al. 2013).
Since brain fingerprinting uses cognitive brain responses, brain fingerprinting does not depend on the emotions of the subject, nor is it affected by emotional responses (Encyclopedia of Forensic Science 2014, Farwell & Smith 2001, Farwell 1992a, 1995a, Farwell 2012). Brain fingerprinting is fundamentally different from the polygraph (lie detector), which measures emotion-based physiological signals such as heart rate, sweating, and blood pressure (Encyclopedia of Forensic Sciences 2013, Farwell 1994). 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 (Encyclopedia of Forensic Science 2014, Farwell & Smith 2001, Harrington v. State 2001, Farwell 2012).
By comparing the responses to the different types of stimuli, the brain fingerprinting system mathematically computes a determination of "information present" (the subject knows the crime-relevant information contained in the probe stimuli) or "information absent" (the subject does not know the information) and provides a statistical confidence for the determination. This determination is mathematically computed and does not involve the subjective judgment of the scientist (Encyclopedia of Forensic Science 2014, Farwell et al. 2013).
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 to identify individuals with specific training or expertise such as members of dormant terrorist cells or bomb makers. 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.
The technique is described in Dr. Farwell's paper "Using Brain MERMER Testing to Detect Concealed Knowledge Despite Efforts to Conceal", published in the Journal of Forensic Sciences in 2001 by Dr. Farwell and FBI Supervisory Special Agent Sharon Smith of the FBI (Farwell & Smith 2001), and in other peer-reviewed publications. For reviews, see Encyclopedia of Forensic Science 2014, Farwell 2012; see also Farwell et al. 2013.
These papers describe tests of brain fingerprinting, a technology based on EEG that detects 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 is significant in context (e.g., in the context of a crime) (Gaillard & Ritter 1983, Farwell & Donchin 1991). When an irrelevant stimulus is presented, a P300 is not expected to occur (Picton 1988, Farwell & Donchin 1991, Farwell & Smith 2001). The P300 is widely known in the scientific community and is also known as an oddball-evoked P300 (see Harrington v. State 2001 and P300).
While researching the P300, Dr. Farwell created a more detailed test that not only includes the P300, but also observes the stimulus response up to 1,400 milliseconds after the stimulus. He calls this brain response a P300-MERMER. The P300, an electrically positive component, is maximal at the midline parietal area of the head and has a peak latency of approximately 300 to 800 milliseconds. The P300-MERMER includes the P300 and also includes an electrically negative component, with an onset latency of approximately 800-1,200 ms (Encyclopedia of Forensic Science 2014, Farwell 1994, Farwell & Smith 2001, Farwell 2012, Farwell et al. 2013). According to Dr. Farwell, the P300-MERMER includes additional features involving changes in the frequency of the EEG signal, but for the purposes of signal detection and practical application the P300-MERMER, is sufficiently characterized by the P300 and the following negative component in the brain response (Encyclopedia of Forensic Science 2014, Farwell 1994, Farwell 2012, Farwell et al. 2013).
Current uses and research
Brain fingerprinting has two primary applications: 1) detecting the record of a specific crime, terrorist act, or incident stored in the brain (Encyclopedia of Forensic Science 2014, Farwell & Smith 2001, Farwell et al. 2013), and 2) detecting a specific type of knowledge, expertise, or training, such as knowledge specific to FBI agents, ISIL-trained terrorists, or bomb makers (Encyclopedia of Forensic Science 2014, Farwell 1992b, Farwell et al. 2013). For reviews, see Encyclopedia of Forensic Science 2014 and Farwell 2012.
The seminal paper by Dr. Farwell and Emmanuel Donchin (Farwell & Donchin 1991) reported the successful application of the technique in detecting knowledge of both laboratory mock crimes and real-life events, with no false positives and no false negatives.
In a study with the FBI, Dr. Farwell and FBI scientist Drew Richardson, former chief of the FBI's chem-bio-nuclear counterterrorism unit, used brain fingerprinting to show that test subjects from specific groups could be identified by detecting specific knowledge which would only be known to members of those groups (Farwell et al. 2013). A group of 17 FBI agents and 4 non-agents were exposed to stimuli (words, phrases, and acronyms) that were presented on a computer screen. The probe (situation-relevant) stimuli contained information that would be known only to someone with FBI training. Brain fingerprinting correctly distinguished the FBI agents from the non-agents.
The CIA has also funded Farwell's research (Dale 2001). In a study funded by the CIA, Farwell and colleagues (Farwell et al. 2014) used brain fingerprinting to detect which individuals had US Navy military medical training. All 30 subjects were correctly determined to have or not to have the specific information regarding military medicine stored in their brains. In another CIA-funded study, brain fingerprinting correctly detected individuals who had participated in specific real-life events, some of which were crimes, based on the record stored in their brains. The error rate was again 0%; accuracy was 100% (Farwell et al. 2013). Dr. Farwell collaborated with FBI scientist Sharon Smith in a further study where brain fingerprinting detected real-life events that was published in the Journal of Forensic Sciences (Farwell & Smith 2001).
Dr. Farwell's recent studies, many conducted by former FBI scientist Dr. Drew Richardson, have mostly involved detecting real-life information in field conditions. Farwell and Richardson applied brain fingerprinting in detecting information regarding actual crimes with real-world judicial consequences, including multiple murders (Encyclopedia of Forensic Science 2014, Farwell et al. 2013). In one study they tested brain fingerprinting in detecting information unique to bomb makers [experts in improvised explosive devices (IEDs)], for application in national security and counterterrorism. Error rate was 0%, with 100% of subjects in these studies were correctly detected (Farwell et al. 2013). Dr. Farwell has also offered a $100,000 reward for beating a brain fingerprinting field test (KOMO News). To date, no one has ever succeeded in doing so (Encyclopedia of Forensic Science 2014, Farwell et al. 2013).
Use in criminal investigation
Farwell's brain fingerprinting has been ruled admissible in court in the reversal of the murder conviction of Terry Harrington (Harrington v. State 2001, Encyclopedia of Forensic Science 2014, Farwell & Makeig 2005). Following a hearing on post-conviction relief on November 14, 2000, an Iowa District Court stated that the fundamental science involved in Dr. Farwell's brain fingerprinting P300 test was well established in the scientific community. For a range of reasons, the court dismissed the defendant's petition for a new trial.
In order to be ruled admissible under the prevailing Daubert standard established by the US Supreme Court, the District Court required proof that brain fingerprinting 1) has been tested and proven, 2) has been peer reviewed and published, 3) produces a known (and low) error rate and is systematically applied, and 4) is well accepted in the relevant scientific community. In ruling the brain fingerprinting test admissible as scientific evidence, the Court stated the following:
- "In the spring of 2000, Harrington was given a test by Dr. Lawrence Farwell. The test is based on a 'P300 effect'."
- "The P-300 effect has been recognized for nearly twenty years."
- "The P-300 effect has been subject to testing and peer review in the scientific community."
- "The consensus in the community of psycho-physiologists is that the P300 effect is valid."
- "The evidence resulting from Harrington's ‘brain fingerprinting’ test was discovered after the fact. It is newly discovered."
As the Iowa District Court clearly stated, the results of the brain fingerprinting test on Harrington constituted "evidence" that the court admitted. Also, Dr. Farwell's testimony as an expert witness and the testimony of the other two expert witnesses in the case were admitted as evidence. The Iowa court admitted the brain fingerprinting evidence and Dr. Farwell's testimony on it under the Daubert standard.
Several authors of law articles have examined the admissibility of brain fingerprinting evidence in the Harrington case in depth and detail and summarized the outcome as follows:
- "The Judge in Harrington ruled Brain Fingerprinting admissible under Daubert after conducting a day-long hearing featuring three expert witnesses, each renowned in his field." (Roberts in Yale Journal of Law and Technology 2007, p. 265)
- "In Harrington, the court admitted Dr. Farwell's testimony on brain fingerprinting and stated that it satisfied the Daubert test." (Moenssens in University of Missouri-Kansas City Law Review, p. 26)
- "[T]he [Harrington] court admitted Brain Fingerprinting evidence based upon the P300 effect…" (Erickson in Drake Law Review, p. 13)
The court noted the distinction, however, between admissibility and weight. In light of the circumstances of a particular case, the admissible evidence does not always have sufficient weight to produce a verdict in favor of the side that proffers the evidence. Although the court ruled brain fingerprinting admissible, the court ruled that the weight of the brain fingerprinting evidence and other evidence proffered by Harrington would probably not have been sufficient to change the verdict in the original trial.
"The court determined that Brain Fingerprinting was new evidence not available at the original trial and that it was sufficiently reliable to merit admission of the evidence; however, the court did not regard its weight as sufficiently compelling in light of the record as a whole as meeting its exacting standard, and thus it denied a new trial on this and the other grounds asserted by Harrington." (Farwell and Makeig in Open Court, p. 9)
The court ruled in Harrington's favor on two major issues but nevertheless denied him a new trial. The court ruled brain fingerprinting and the testimony of the expert witnesses on it was admissible, and also admitted the recantation testimony of the only alleged witness to the crime, yet nevertheless denied Harrington's petition for a new trial. Regarding this rather complicated ruling, one commentator opined that "[t]he Harrington court avoided a clear ruling on admissibility" (Denno 2002) of the test.
Harrington appealed to the Iowa Supreme Court. The Iowa Supreme Court reversed the trial court and granted Harrington a new trial. (Harrington v. State 2003, p. 516) The supreme court did not reach the brain fingerprinting issue and decided the case on other grounds. "Because the scientific testing evidence is not necessary to a resolution of this appeal, we give it no further consideration." (Harrington v. State 2003, p. 516)
Although the Iowa Supreme Court did not rule on brain fingerprinting, they allowed the law of the case established by the district court to stand, implicitly including the district court's finding regarding the admissibility of the newly discovered evidence resulting from Harrington's Brain Fingerprinting test. (Harrington v. State 2003)
Due to a constitutional rights violation, specifically a Brady disclosure violation, by the State of Iowa in the original trial, the Iowa Supreme Court awarded Harrington a new trial. The only alleged witness to the crime, Kevin Hughes, recanted when Dr. Farwell confronted him with the "information absent" results of the brain fingerprinting test on Harrington. Without its star witness, the state subsequently dismissed the murder prosecution without prejudice for lack of evidence due to witness recantations and the passage of time.
The State of Iowa argued unsuccessfully in trial court that the brain fingerprinting results should not be considered admissible "evidence," whether "newly discovered" or not (Harrington v. State 2001).
In his recantation, Hughes stated under oath under questioning by Farwell that the detectives and prosecutors had told him he would go to prison for life if he did not implicate Harrington. He stated that when he agreed to falsely accuse Harrington of the murder, they coached him in fabricating the story to which he later testified in the trial. He stated that when he said something that contradicted known facts – such as identifying the wrong murder weapon – they corrected him, and he changed his story accordingly. (Harrington v. State 2001)
Harrington sued the prosecutors and the State of Iowa for framing him. The prosecutors and the State of Iowa did not deny the accusations brought by Hughes and Harrington. Their defense was that they enjoyed absolute immunity due to their professional positions. The U.S. Supreme Court agreed to hear the case on the issue, as reported in the TIME Magazine article, "When Is It Legal to Frame a Man for Murder?" (TIME Magazine article on Harrington) (TIME 2009). However, before the Supreme Court heard the case, the State of Iowa settled with Harrington and another man falsely convicted of the same crime. The state paid them a $12 million settlement (L A Times 2010).
Brain fingerprinting testing was also instrumental in bringing serial killer James B. Grinder to justice. In August 1999, Dr. Farwell conducted a brain fingerprinting test on Grinder at the request of Sheriff Robert Dawson of Macon County, Missouri. The test proved that information stored in his brain matched the details of the murder of Julie Helton (Encyclopedia of Forensic Science 2014, Farwell et al. 2013, Farwell 2012). Faced with a certain conviction and almost certain death sentence, Grinder then pled guilty to the rape and murder of Julie Helton in exchange for a sentence of life in prison without parole. He is currently serving that sentence and has also confessed to the murders of three other young women.
Limitations of brain fingerprinting
Both the strengths and limitations of brain fingerprinting are documented in detail in the expert witness testimony of Dr. Farwell and two other expert witnesses in the Harrington case (Harrington v. State 2001) as well as in Farwell's publications and patents (e.g., Farwell 1994, Farwell 1995a, b, Farwell & Smith 2001, Farwell 2012) and other scientific publications (e.g., Encyclopedia of Forensic Science 2014). The limitations of brain fingerprinting described below are also summarized in PBS TV, PBS Innovation Series – "Brain Fingerprinting: Ask the Experts".
Brain fingerprinting detects information-processing brain responses that reveal what information is stored in the subject's brain. It does not detect how that information got there. This fact has implications for how and when the technique can be applied. In a case where a suspect claims not to have been at the crime scene and has no legitimate reason for knowing the details of the crime, and investigators have information that has not been released to the public, brain fingerprinting can determine objectively whether or not the subject possesses that information. In such a case, brain fingerprinting can provide useful evidence.
If, however, the suspect knows everything that the investigators know about the crime for some legitimate reason, then the test cannot be applied. There are several circumstances in which this may be the case. If a suspect acknowledges being at the scene of the crime, but claims to be a witness and not a perpetrator, then the fact that he knows details about the crime would not be incriminating. There would be no reason to conduct a test, because the resulting "information present" response would simply show that the suspect knew the details about the crime – knowledge which he already admits and which he gained at the crime scene whether he was a witness or a perpetrator.
Another case where brain fingerprinting is not applicable would be one wherein a suspect and an alleged victim – say, of an alleged sexual assault – agree on the details of what was said and done, but disagree on the intent of the parties. Brain fingerprinting detects only information and not intent. The fact that the suspect knows the uncontested facts of the circumstance does not indicate which party's version of the intent is correct.
Obviously, in structuring a brain fingerprinting test, a scientist must avoid including information that has been made public. Detecting that a suspect knows the information he obtained by reading a newspaper would not be of use in a criminal investigation, and standard brain fingerprinting procedures eliminate all such information from the structuring of a test (Encyclopedia of Forensic Science 2014, Farwell 1995a, Harrington v. State 2001, Farwell 2012). News accounts containing many of the details of a crime do not interfere with the development of a brain fingerprinting test; however, they simply limit the material that can be tested. Even in highly publicized cases, there are almost always many details that are known to the investigators but not released to the public (Farwell 2012), and these can be used as stimuli to test the subject for knowledge that he or she would have no way to know except by committing the crime.
Another situation where brain fingerprinting is not applicable is one where the authorities have no information about what crime may have taken place. For example, an individual may disappear under circumstances where a specific suspect had a strong motive to murder the individual. Without any evidence, authorities do not know whether a murder took place, if the individual decided to take a trip and did not tell anyone, or if some other criminal or non-criminal event happened. If there is no known information on which a suspect could be tested, a brain fingerprinting test cannot be structured.
Similarly, brain fingerprinting is not applicable for general screening, for example, in general pre-employment or employee screening wherein any number of undesirable activities or intentions may be relevant. If the investigators have no idea what crime or undesirable act the individual may have committed, there is no way to structure appropriate stimuli to detect the telltale knowledge that would result from committing the crime. Brain fingerprinting can be used for specific screening or focused screening, when investigators have some idea what they are looking for. ).
Brain fingerprinting does not detect lies; it simply detects information. No questions are asked or answered during a brain fingerprinting test. The subject neither lies nor tells the truth during a brain fingerprinting test, and the outcome of the test is unaffected by whether he has lied or told the truth at any other time. The outcome of "information present" or "information absent" depends on whether the relevant information is stored in the brain and not on what the subject says about it (Encyclopedia of Forensic Science 2014, Farwell 1994, PBS TV, Farwell 2012).
Brain fingerprinting does not determine whether a suspect is guilty or innocent of a crime. This is a legal determination to be made by a judge and jury, not a scientific determination to be made by a computer or a scientist (Encyclopedia of Forensic Science 2014, Farwell 1994, PBS TV, Farwell 2012). Brain fingerprinting can provide scientific evidence that the judge and jury can weigh along with the other evidence in reaching their decisions regarding the crime. To remain within the realm of scientific testimony, a brain fingerprinting expert witness must testify only regarding the scientific test and information stored in the brain revealed by the test, as Dr. Farwell did in the Harrington case (Harrington v. State 2001). Like the testimony of other forensic scientists, a brain fingerprinting scientist's testimony does not include interpreting the scientific evidence in terms of guilt or innocence. A DNA expert may testify that two DNA samples match, one from the crime scene and one from the suspect, but he or she does not conclude "this man is a murderer." Similarly, a brain fingerprinting expert can testify to the outcome of the test that the subject has specific information stored in his or her brain about the crime (or not), but the interpretation of this evidence in terms of guilt or innocence is solely up to the judge and jury (Harrington v. State 2001, PBS TV).
Just as all witness testimony depends on the memory of the witness, brain fingerprinting depends on the memory of the subject. Brain fingerprinting results must be viewed in light of the limitations on human memory and the factors affecting it (Harrington v. State 2001, PBS TV). Brain fingerprinting can provide scientific evidence regarding what information is stored in a subject's brain. It does not determine what information should be, could be, or would be stored in the subject's brain if the subject were innocent or guilty. It only measures what actually is stored in the brain (Encyclopedia of Forensic Science 2014, Farwell 2012). How this evidence is interpreted, and what conclusions are drawn based on it, are outside the realm of the science and the scientist. This is up to the judge and jury. It is up to the prosecutor and the defense attorney to argue, and the judge and jury to decide, the significance and weight of the brain fingerprinting evidence in making a determination of whether or not the suspect committed the crime.
Like all forensic science techniques, brain fingerprinting depends on the evidence-gathering process, which lies outside the realm of science, to provide the evidence to be scientifically tested. Before a brain fingerprinting test can be conducted, an investigator must discover relevant information about the crime or investigated situation. This investigative process, in which the investigator gathers the information to be tested from the crime scene or other sources related to the crime, depends on the skill and judgment of the investigator. This process is outside the scientific process; it precedes the scientific process of brain fingerprinting. This investigative process produces the probe stimuli to be tested. Brain fingerprinting science only determines whether the information tested is stored in the brain of the subject or not. It does not provide scientific data on the effectiveness of the investigation that produced the information about the crime that was tested. In this regard, brain fingerprinting is similar to other forensic sciences. A DNA test determines only whether two DNA samples match. It does not determine whether the investigator did an effective job of collecting DNA from the crime scene. Similarly, a brain fingerprinting test determines only whether or not the information stored in the suspect's brain matches the information contained in the probe stimuli. This is information that the investigator provided to the scientist to test scientifically, based on the investigative process that is outside the realm of science. In making their determination about the crime and the suspect's possible role in it, the judge and jury must take into account not only the scientific determination of "information present" or "information absent" provided by the brain fingerprinting test; they must also make common-sense, human, non-scientific judgments regarding the information gathered by the investigator and to what degree knowledge or lack of knowledge of that information is probative regarding the suspect's possible role in the crime (Harrington v. State 2001, Farwell1995a, Farwell 2012). Brain fingerprinting is not a substitute for effective investigation on the part of the investigator or for common sense and good judgment on the part of the judge and jury (PBS TV).
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- ABC-TV Good Morning America: Charles Gibson interviews Dr. Lawrence Farwell "Mind-Reading Technology Tests Subject's Guilt -- Brain-Reading Technology Becomes New Tool in Courts," March 9, 2004. Accessed September 15, 2014.
- PBS Special Report on Brain Fingerprinting and Interactive Website. Accessed September 15, 2014.
- “Brain fingerprinting: a comprehensive tutorial review of detection of concealed information with event-related brain potentials.” Peer-reviewed article by Dr. Larry Farwell in Cognitive Neurodynamics. Accessed September 15, 2014.
- “Brain fingerprinting field studies comparing P300-MERMER and P300 brainwave responses in the detection of concealed information.” Peer-reviewed article by Farwell, Richardson, and Richardson on brain fingerprinting research at the FBI and the CIA, and in detecting real crimes and bomb makers,published in Cognitive Neurodynamics. Accessed September 15, 2014.
- “Brain fingerprinting classification concealed information test detects US Navy military medical information with P300.” Peer-reviewed article by Farwell, Richardson, Richardson, and Furedy on CIA-sponsored brain fingerprinting research at the US Navy published in Frontiers in Neuroscience. Accessed May 31, 2015.
- Popular Science: The Future of…Security – Brain Fingerprinting. Accessed September 15, 2014.
- PBS Innovation Series Special on Brain Fingerprinting – "Brain Fingerprinting: Ask the Experts" Accessed September 15, 2014.
- "BRAIN FINGERPRINTING: IS THE SCIENCE THERE?", Neurology Today, November 2004, by Mark Moran. Accessed September 15, 2014.
- Discussion of legal and scientific critiques of Dr. Farwell's theories Accessed September 15, 2014.
- "It's the thought that counts for the guilty", The Observer, April 25, 2004. Accessed September 15, 2014.
- Federal Agency Views on the Potential Application of "Brain Fingerprinting" 2001 Report to the Honorable Charles E. Grassley, U.S. Senate