Introduction

            On May 21, 2000, Dr. Lawrence Farwell prepared a Forensic Science Report on a Brain Fingerprinting Test on Terry Harrington regarding the murder of John Schweer (Re: State of Iowa vs. Terry Harrington In the Iowa District Court for Pottawattamie County at Council Bluffs).  This Supplement provides additional scientific and technical detail and perspective, and is an integral part of said report. 

            In preparing scientific reports, there are always tradeoffs.  One tradeoff, particularly in forensic applications, is between using the most advanced and up-to-date science and technology, which will yield the highest accuracy and effectiveness, versus using somewhat older techniques and concepts that have had time to accumulate a longer track record, including more testing, peer-reviewed publications, and acceptance in the scientific community. 

            This supplement seeks to address this tradeoff in the following way.  The previous report emphasized cutting-edge science and technology.  This report will fill in the perspective and data provided by more traditional and more well established science and technology.  The conclusion that this will lead to is that all of the same scientific determinations and conclusions reached in the previous report can be substantiated on the basis of the most traditional and well-accepted methods and scientific theories in the field.  The statistical confidence is higher with the newer discoveries and techniques developed by the author, but the scientific determinations and conclusions are identical to those that are reached by using more traditional techniques that have been extensively tested, have achieved extensive peer review and voluminous publication, and enjoy unquestioned validity and acceptance in the scientific  community.  The accuracy rates achieved using traditional methods, though not quite as high as those achieved using the innovations described by the author in recent publications and in the initial report, are nevertheless near perfect. 

            A second tradeoff is between expressing the science and technology in terms understandable to a layman versus including all of the scientific and technical details that will allow one's scientific peers to understand and appreciate the scientific merit and technical soundness of the science and technology described.  This Supplement addresses both sides of this tradeoff.  We have included herein both more extensive explanations of the science and technology of Brain Fingerprinting in lay terms and more detailed technical and scientific descriptions of the scientific method, apparatus, and procedures employed.

            In order to bring out the relevant information in a format that is accessible, clear, appropriate, and applicable to legal proceedings, much of this supplement has been constructed in a question-and-answer format.

Questions and Answers

Research, Publications, and Funding

QUESTION: Have you published in the field of Brain Fingerprinting or brain-wave-based information detection?

DR. FARWELL: I have published in the leading peer-reviewed journals in the relevant scientific field, including Psychophysiology, Electroencephalography and Clinical Neurophysiology  or EEG Journal, and with Sharon Smith of the FBI in the Journal of Forensic Sciences.  I have also published in other prestigious publications such as Advances in Brain Research, Progress in Brain Research, Annual Review of Gerontology and Geriatrics, and others.  My CV is a part of the original report.

 QUESTION: Where have you conducted research?

DR. FARWELL: In addition to the University of Illinois and Harvard, I have conducted research on FBI agents at the FBI Academy in Quantico, research under contract with the CIA, and research at the US Navy.

 QUESTION: Did you receive funding from the CIA or the FBI, and how much?

ALLEGED WITNESS: My laboratory was funded by the CIA for three years, for a total of about a million dollars. My research at the FBI was approved by the FBI but not funded by the FBI. (I didn't need or apply for FBI funding at the time, because I was funded by the CIA.) The Navy study was done in collaboration with the CIA, and was funded by the CIA.

 QUESTION: Does you CV contain all of the jobs and professional activities you have participated in throughout your life?

ALLEGED WITNESS: No. It contains those professional activities that I deem relevant to my expertise in Brain Fingerprinting.  I have not included professional activities and jobs that are not relevant. For example, I have a black belt in kung fu, and have taught kung fu professionally for many years.  I have not included this because it is not relevant. 

What is Brain Fingerprinting Testing?

QUESTION: What is Brain Fingerprinting, and what does it measure?

DR. FARWELL: Brain Fingerprinting is based on the principle that the brain is central to all human acts.  In a criminal act, there may or may not be many kinds of peripheral evidence, but the brain is always there, planning, executing, and recording the crime.  The fundamental difference between a perpetrator and a falsely accused, innocent person is that the perpetrator, having committed the crime, has the details of the crime stored in his brain, and the innocent suspect  does not.  This is what Brain Fingerprinting detects scientifically.

            Brain Fingerprinting matches evidence from a crime scene with evidence stored in the brain of the perpetrator, similarly to the way conventional fingerprinting matches fingerprints at the crime scene with the fingers of the perpetrator, and DNA fingerprinting matches biological samples from the crime scene with the DNA in the body of the perpetrator.

            Brain Fingerprinting accomplishes this by measuring electrical brain responses to words, phrases, or pictures presented on a computer screen.   Details of the crime that would be known only to the perpetrator and investigators are presented in a sequence, along with other words or pictures that are not relevant to the crime.  We can determine by the brain response if the suspect recognizes the crime-relevant stimuli or not.  This reveals whether or not he has details of the crime that would be known only to the perpetrator stored in his brain.

            The brain waves are measured non-invasively from the scalp with a headband equipped with sensors.  The signals are amplified, digitized, and analyzed by a computer.

Accuracy of Brain Fingerprinting Testing

QUESTION: How accurate is Brain Fingerprinting?

DR. FARWELL: Brain Fingerprinting makes a determination as to whether or not the crime-relevant information is stored in the brain.  The determination can be "information present," "information absent," or, if insufficient data are available to make a clear determination, the result is "indeterminate" -- i.e., no clear determination can be made.  The system also provides a statistical confidence for each determination.  100% of the determinations (i.e. information present or information absent) have been correct, and we have made such a definite determination in 97% of cases.  About 3% of cases have resulted in an indeterminate result.  "Indeterminate" is not an error; it simply means there is insufficient data for a clear determination.  All of the indeterminate results were in the early research, without some of the more modern refinements.

 QUESTION: If 100% of the determinations made were correct, does this mean that Brain Fingerprinting is "100% accurate," that it will always solve every crime and can never make a mistake?

DR. FARWELL: In science, nothing is absolutely 100%.  There is always a level of uncertainty.  Fortunately, when we encounter a situation where no definite determination can be made with a high statistical confidence, then the system produces an "indeterminate" result.  This is done mathematically.  This  avoids making an error when there is insufficient data, and also avoids the scientifically untenable position of claiming that the system is perfect and could never fail to give us a definite and accurate solution to any crime.  Like any scientific evidence, the information provided by Brain Fingerprinting is not be taken as an absolute.  It must be evaluated and weighed along with all of the other available evidence.

Scientific basis of Brain Fingerprinting Testing

QUESTION: Describe the scientific basis of Brain Fingerprinting.

DR. FARWELL: Brain Fingerprinting is an application of the science of cognitive psychophysiology.  The neurons in the brain fire electrically.  When the brain processes information, neurons fire in specific patterns.  These patterns of electrical impulses can be measured non-invasively from the scalp, and from that we can tell what information processing tasks the brain is undertaking.  We put a headband with sensors on the head, amplify the signals, feed them into a computer, and analyze the brain waves.

            The brain responses that measure specific cognitive actions by the brain are called event-related brain potentials.  That is, they are related to an event.  For example, let's say an elephant came in the door of this room.  We would notice it.  We wouldn't have a choice about that.  Once we noticed it, we would have lots of choices what to do -- we could feed it, run away, etc.  But we would have no choice about noticing it.  When we take note of something there is a specific brain-wave pattern that occurs that can be measured from the scalp and analyzed by computer. 

 QUESTION: What do you mean by taking note of something?

DR. FARWELL:  Let's use an example.  Right now we're in a courtroom.  We know what's in the room and what kind of events generally happen in this room. If we close our eyes, we can't see the courtroom, but we still know we're here, because we have this information stored in our brain. In other words, we know the context we are now in; this context is stored in our brain.  That internal representation of the current operating environment is called a schema, sort of a map of where we are, not just physically, but it includes the rules we know about how things happen in this kind of environment. 

            Say the door opens over there and an elephant comes into the room.  Now the context has changed.  We now have a room with an elephant.  We need to be able to update the schema we have in our brain to include this change.  This is known as context updating.  It's a fundamental information-processing function that we all do.  We have to do it to function and survive in a changing environment.

            When we engage in this information-processing function, the neurons in our brain fire in certain patterns, and this creates electrical activity that can be measured at the scalp.  The particular pattern of electrical brain activity that takes place during context updating -- when we recognize the elephant -- was discovered in 1965 by Sutton and colleagues, and he called it a P300. Later we'll get into some finer distinctions in brain responses and terminology, but the fundamental scientific phenomenon that has been well established since the 60's is context updating and the P300 that it produces on the scalp.  P300 is also known as P3, P3b, late positive complex (LPC), or the positive aspect of the MERMER.

Electroencephalography (EEG) and event-related brain potentials (ERP)

QUESTION: How do scientists measure this brain response?

DR. FARWELL: We attach sensors to the head that pick up electrical signals.  These signals are amplified by an amplifier, converted to a series numbers by a digitizer, recorded, and analyzed by computer.

            Now the brain is not only doing the thing we are interested in, it's also doing lots of other things at the same time.  So scientists, starting about half a century ago, had to develop a way of isolating the signal from the noise -- that is, the response we're looking for from everything else the brain is doing. 

QUESTION: How did they do this?

DR. FARWELL: Let's use an example.  When you hear a click in the ear, the signal goes to seven different parts of the brain in the first 1/100^th of a second.  There is a specific recognizable blip in the brain-wave pattern for each of these, but you can't see them from looking at the raw signal because they're tiny, and there is so much else going on.  So what scientists did is to present the click many times, and average the response. This is called signal averaging. Then everything that is not time-locked to the signal averages out to zero, and you can clearly see the response.

            These responses are called event-related potentials, because they are related to an event, in this case hearing a click in the ear.  Detecting event-related potentials through signal averaging is the most well established method for detecting specific, short-term brain activity, and has been for half a century.

            Initially, the event-related potentials studied were measures just of sensory processing of a stimulus, like the clicks.  These are called exogenous event-related potentials, or evoked potentials.  They just measure sensory activity.  At first, scientists only measured a very brief time after the stimulus, and these sensory potentials were all they detected.

            But the brain does much more interesting things than just sensory activity.  When we perceive a meaningful stimulus, we process it cognitively.  After the sensory input comes in, we recognize it, we take note of its significance in the current context.  This is accomplished by the brain.  As science progressed, scientists discovered the event-related potentials that manifest at the scalp when this kind of process is undertaken by the brain.  This is a second type of event-related potentials.  They are called endogenous event-related potentials, or cognitive event-related potentials, because they are a manifestation of cognitive information-processing activity in the brain, not just sensory processing.  Instead of just the first few hundredths of a second, these potentials take place on the time scale of up to a second or two.  They are the manifestation on the scalp of the process that the brain undertakes when the brain processes specific information.

            We talked before about context updating, when we take note of something that is significant in the current context.  This is manifested by a P300. The P300 that was discovered in the 1960's is probably the most thoroughly researched event-related brain potential.

The well established scientific phenomenon applied in Brain Fingerprinting Testing

QUESTION: How well established is this as a scientific phenomenon?

DR. FARWELL: It is at least as well established as any phenomenon in this realm of science.  This was first discovered in the 1960's.  In 1965 Dr. Sam Sutton and his colleagues first reported a specific brain response that takes place when you take note of something.  They called it a P300.

            Since Sutton et al. discovered the P300, there have been hundreds, perhaps over a thousand articles published in peer-reviewed journals on the P300.  It is probably the most thoroughly researched and published phenomenon in the entire field of cognitive psychophysiology.  It has been found to be an extremely reliable indicator of when someone takes note of something, or context updating.

QUESTION: Has this been independently verified in other laboratories, and have their results been published?

DR. FARWELL: Yes, extensively. As I said, the science of this is perhaps the most well established phenomenon in all of cognitive psychophysiology, with hundreds or perhaps even thousands of studies from many different laboratories published frequently in every relevant journal over the last several decades. 

            This specific application has been published in prestigious peer-reviewed journals not only repeatedly by myself and my colleagues, including Sharon Smith of the FBI, but also repeatedly by several others, including Iacono, Allen, and colleagues, Rosenfeld and colleagues, and Rapp and Bashore.  I have published this specific application not only in Psychophysiology, a leading journal in this kind of brain research, but also to be published in January in the Journal of Forensic Sciences, a leading journal in forensic science.  Iacono and Rosenfeld have published in Psychophysiology and other journals.  Bashore and Rapp published in Psychological Bulletin, another prestigious peer-reviewed journal.

Fundamentally different from lie detection

QUESTION: What does this have to do with lie detection?

DR. FARWELL: Absolutely nothing.  Brain Fingerprinting detects information stored in the brain.  The results are exactly the same whether the person lies or tells the truth about this information or any other subject.  If a person's fingerprints or DNA match (or don't match) the fingerprints or DNA at a crime scene, this fact does not change in any way if the person lies or tells the truth about it.  The same is true of Brain Fingerprinting.  All it detects is the presence or absence of information, and this is completely independent of the process of lying or telling the truth.  Lying or telling the truth in no way affects the outcome of a Brain Fingerprinting test.  Brain Fingerprinting detects information, not lying. The fundamental differences between Brain Fingerprinting and psychophysiological detection of deception are covered in more detail in Appendix 1.

How the system works

QUESTION: How does Brain Fingerprinting use this science to detect criminals and exonerate innocent people?

DR. FARWELL: What we want to determine is whether or not someone has committed a crime.  The fundamental difference between a perpetrator and an innocent suspect, of course, is that the perpetrator actually committed the crime, so he has a record of that crime stored in his brain, while the innocent suspect does not.  Brain Fingerprinting detects this record stored in the brain by measuring brain responses to stimuli -- words, phrases, or pictures flashed on a computer screen.

QUESTION: How is this done?

DR. FARWELL:  Recall that we have a brain response, the P300, that the brain emits when it recognizes and processes a stimulus that is significant in the current context.  This has been well established over the last 35 years.  All we do is to present stimuli that will be recognized by the perpetrator as significant, but will not be recognized by an innocent suspect.  So we flash a series of words, phrases, or pictures on a computer screen.  Some of these stimuli are relevant to the crime and will be recognized by the criminal, but are not known to an innocent suspect.  We mix these crime-relevant words or pictures in with other stimuli that would be equally plausible for an innocent suspect. In Brain Fingerprinting, a computer analyzes the brain response to detect the P300, and thus determines scientifically whether or not the specific crime-relevant information is stored in the brain of the suspect. 

QUESTION: What about the MERMER?

DR. FARWELL: MERMER is an acronym for memory and encoding related multifaceted electroencephalographic response.  It's a more extensive response than the P300, and it contains the P300.  When you have a MERMER, you always have a P300, because the P300 is part of the MERMER.  The P300 is simpler to measure and to understand, and it’s a more thoroughly established scientific phenomenon.  As a cutting-edge scientific discovery, the MERMER is of scientific interest, but we don't need anything but the P300 to arrive at a clear determination, with a high statistical confidence, in the Harrington case.  If we want to stick to the tried and true basics, we can use the term P300; if we want to be a little more up-to-date and comprehensive, we can use the term MERMER. 

QUESTION: Is the system you just described the one you used on Harrington? Is it the same as the system used in other studies?

DR. FARWELL: Yes. The system I used on Harrington is essentially the same system used by Dr. Drew Richardson of the FBI and myself in our research on FBI agents, in the studies we did for the CIA, in the research Dr. Rene Hernandez and I conducted for the US Navy, and in the research I am publishing with Sharon Smith of the FBI.  It’s essentially the same as the system Emanuel Donchin and I used in our published research, and as far as the fundamentals and scientific foundations, it's essentially the same as the system used in replications in other laboratories.

The scientific procedure

QUESTION: Exactly what happens during the Brain Fingerprinting test? Can you give more details?

DR. FARWELL: A subject views a series of words or short phrases on a computer. (We can also use pictures, but we usually use words and did so with Harrington.)  Each phrase is flashed for just long enough to read it and see what it means, in Harrington's case, four tenths of a second,.  There are three different kinds of phrases.  Some of the stimuli are things that the subject knows and will recognize, and we make sure he knows these things.  We call these Targets.  To make sure the subject recognizes the Targets, we give him a list of them, and we instruct the subject to press a special button with one thumb when any one of them appears.  So, we know the subject will take note of the Targets. 

QUESTION: What happens when someone takes note of the Targets?

DR. FARWELL: When someone takes note of something, the brain engages in a specific pattern of electrical brain activity that we can measure from the scalp, a MERMER that contains a P300.  Again, I will not get into the technical differences in terminology at this point, because they are not relevant to the basic point or the Harrington results.  It's not necessary to deal with all the technical details to understand the result we obtained in the research and the test with Harrington.  In other words, the fundamental science and the results are the same however you deal with the technical fine points.  I'm going to talk in terms of the P300 for the time being, because that is sufficient to make the necessary scientific points, and also sufficient to obtain the results we obtained with Harrington.

QUESTION: OK, so the person recognizes and notices these things that he knows, and you get a specific brain response called a P300 or a MERMER.  How does this identify a perpetrator?

DR. FARWELL: We need to describe two other kinds of stimuli to get to that point.  The second type of stimuli is phrases that are irrelevant to the subject. These are called Irrelevants. Since these items are irrelevant, that is, they are not significant or noteworthy to the subject in the present context, they do not elicit a P300.

            The stimuli of the third type are the most important ones.  These stimuli are details about the crime that would be known to the subject if he had participated in the crime, but that he would have no way of knowing otherwise. These are called Probes.  These Probes are mixed in with the Irrelevant stimuli, so that a subject who has not participated in the crime will not even know which ones they are.  A subject who participated in the crime, however, will recognize the Probes because they refer to things involved in the crime that he knows about.

            The brain responses to the Probes distinguish whether the person participated in the crime or not.

            If the suspect participated in the crime, he recognizes these crime-relevant stimuli, and his brain produces a P300.  If he is did not participate in the crime and consequently does not know the details about it, he does not recognize these Probe stimuli -- for him, they're indistinguishable from the Irrelevants -- and his brain does not produce a P300.

            The Irrelevants are designed to be equally plausible for a subject who did not participate in the crime, so a subject lacking this crime-relevant knowledge won't even know which stimuli are relevant to the crime.  His is brain will not produce a P300 in response to the Probes.

            Let me give you an example.  Say that the investigated situation involved an espionage crime in which the subject had to find a contact with a blue coat.  "Blue coat" could be a Probe stimulus.  "Red scarf" could be an Irrelevant stimulus.  If someone had not participated in the event, he would not know the difference.  If someone had participated, however, he would recognize the significance of "blue coat."   For a subject who knows about the crime, the brain response to "blue coat" would contain a P300.

            Thus, we have three types of stimuli.  The Targets are things the subject knows, and we know he knows them, and they will produce a brain response with a P300.  The Irrelevants are irrelevant to the subject, and will not produce a P300.  The Probes are relevant to the crime and known only to the perpetrator and investigators, but not to others.  So for a person lacking the crime-relevant knowledge we are testing for, the Probes will not produce a P300 -- like the Irrelevants.  For a person who has the crime-relevant knowledge we are testing for, the Probes will produce a P300 -- like the Targets.

QUESTION:  Could a person beat this system by controlling his response?

DR. FARWELL:  No. Remember the elephant coming into the room?  The first thing we do is to notice the elephant.  After we've noticed him, we can choose to do any number of things -- feed him, run away, etc. -- but we don't have any choice about noticing him and recognizing that this is an elephant.  When we flash stimuli relevant to a crime on the screen, a person who committed that crime first recognizes them, then decides what to do about it.  Maybe he'll try to look innocent, or look like they mean nothing to him, or whatever.  It doesn't matter.  We pick up our information when  he recognizes the stimulus, before he decides what to do about it.

            There are all kinds of things a person could try to do in an attempt to trick the system if he thought he understood how it works, but such manipulations would be easy to pick out in the data analysis, because we have all of the data, and we can analyze responses to individual stimuli or groups of stimuli.  The bottom line is, we've had experts at the Human Brain Research Laboratory -- experts who know exactly how the system works and even people who wrote the software for the data analysis algorithms -- try to beat the system in detecting real-life information, and they can't.  I can't beat it myself.  The information-processing brain function that Brain Fingerprinting detects is a process that takes place automatically when you recognize and take note of a significant stimulus, and you don't have a choice about doing that when such a stimulus is presented.

            A person could refuse to even look at the screen, and then of course we would not get any data, but this would be obvious.  If he pretended to look at the screen but didn't, he could not push the right buttons, and we would know this because we record the button presses.  So, we can't physically force a person to take the test, but if he sits in front of the computer screen and actually pushes the buttons when the Target and Irrelevant stimuli come up, he has to recognize the Probes as well if he has the crime-relevant information, and we'll detect the response.

Limitations on the applicability of Brain Fingerprinting Testing

QUESTION: Is Brain Fingerprinting applicable in every case?

DR. FARWELL: No. Like every other scientific technique, there are limitations on the applicability of Brain Fingerprinting.  DNA and conventional fingerprints, which are very effective technologies, are applicable in only about 1% of cases.  In the vast majority of cases, there are no DNA and no fingerprints at the crime scene.  With Brain Fingerprinting, the brain is always there, planning, executing, and recording the crime.  We can apply Brain Fingerprinting whenever we have a suspect and we have specific details about the crime that would be known only to the perpetrator and investigators, and not to an innocent suspect.  This certainly provides a much higher level of applicability than fingerprints or DNA, but it is not applicable in every single case.  When we don't have and can't get the necessary information, then Brain Fingerprinting is not applicable.  When it's not applicable, obviously we don't apply it. 

            Note that this is a limitation on the applicability, not the reliability or the accuracy of the system.  It's like fingerprints -- where there are none, it's not that the technique will be used and will be inaccurate: the technique simply does not apply and we do not use it.  With Brain Fingerprinting, where we cannot find specific details of the crime that are known only to the perpetrator and investigators, then the technique is not applicable, and we do not use it.

QUESTION: What if the person knows about the crime because he was there, but he was a witness and not a perpetrator?

DR. FARWELL: Brain Fingerprinting will detect what information is in the brain, but will not tell us how it got there.  It's like having fingerprints at the crime scene.  Someone's fingerprints could be there because he was there witnessing the crime and not because he committed it.  In a case where there are two people at a crime scene and only one committed the crime, all Brain Fingerprinting can do is to narrow the search down to two suspects. It can not be used to distinguish why a person was at the crime scene.  This, however, is relatively rare.  In almost every case when a person says he is innocent, he also says he was not there. 

            Like DNA and fingerprints, Brain Fingerprinting matches evidence at a crime scene with evidence on the person of the perpetrator.  It can place a person at the crime scene or exonerate someone who was not there, but in some cases there will be some other reason someone was there other than committing  a crime.  In such cases, we can apply Brain Fingerprinting to narrow the range of suspects to the people who were present at the crime, but we cannot use it to determine which one committed the crime.

QUESTION: What if a suspect read about the crime in the newspaper, or what if he's a suspect and the police told him all about it in interrogation?

DR. FARWELL: If a suspect knows everything we know or could discover about the crime, from some other means other than from committing the crime, then we cannot apply Brain Fingerprinting.  To apply the test, we need some information that the subject will have only if he committed the crime.  This is why it is important to educate law enforcement personnel so that they will not reveal everything they know about a crime to a suspect before a Brain Fingerprinting test can be administered.

QUESTION: What if some of the stimuli are relevant to the subject for some other reason that has nothing to do with the crime?

DR. FARWELL: We go over a list of all the stimuli just before we run the test.  This reinforces the context in which the test is run.  It also gives the subject a chance to tell us if some stimulus is relevant to him for any reason.  If so, we eliminate the stimulus.   Whether he's innocent or guilty, he can be expected to  deny knowing the details of the crime that would be known only to the perpetrator.  If a Probe is significant to a suspect because of the crime, we don't expect him to reveal it to us by saying so.  So a guilty suspect is expected to say he does not recognize the crime-relevant Probes as significant. What he says, however, makes no difference to the outcome of the Brain Fingerprinting test.  If we test him and his brain responses reveal that he does recognize the crime-relevant Probes, there's only one reason why: that he participated in the crime.

Application of Brain Fingerprinting Testing in the Harrington case

QUESTION: Harrington was tried and convicted.  In the course of the trial he heard all about the crime, and that information was stored in his brain.  If you detected that information, it wouldn't prove he participated in the crime, only the trial.  So how did you use Brain Fingerprinting in this case?

DR. FARWELL: We couldn't use any of the information Harrington heard at the trial, because showing that he had this information stored in his brain would not prove anything about the crime.  He would have this information stored in his brain from the trial, not from committing the crime. So we had to find information about the crime that he was never told in the trial.

QUESTION: Was this difficult?

DR. FARWELL: The Harrington case is about as difficult a case as we would ever expect to find, but it was still quite possible to solve it.  If Brain Fingerprinting had been invented in 1977, it would have been a very easy case to solve, but Brain Fingerprinting was not invented until the mid-1980s.  On the day he was picked up for the crime, there were hundreds of details about the crime that Harrington did not know, and that the investigators did know.  We could have easily used these to test Harrington's brain and demonstrate that he did not know a thing about the crime.  But he heard voluminous information about the crime in the interrogations and the trial, so we couldn't use any of that information in a test.  What we had to do was examine the available evidence and develop a test that would include only things he would know about the crime if he committed it, but that he had never been told at the trial.

QUESTION: Were you able to do that?

DR. FARWELL: Yes.

QUESTION: Can you give me an example?

DR. FARWELL:  Yes.  The only alleged witness to the crime was Kevin Hughes, a 16-year-old black who was himself accused of the crime. Hughes told a detailed story about Harrington committing the crime, which he has now recanted.  Hughes' account of the crime was essentially the only evidence against Harrington.  I couldn't test Harrington directly on what Hughes said at the trial -- because Harrington knew this from the trial, not from the crime.  I could, however, use Hughes' testimony, along with police reports, crime scene photos, and the crime scene itself, to determine what the perpetrators must have encountered in committing the crime that Hughes described.  Some of these things that the perpetrators would have had to experience in committing the crime were never mentioned specifically by Hughes or otherwise revealed at trial, so Harrington would have no way of knowing them unless he committed the crime. 

            Fortunately, the basic lay of the land at the crime scene, in terms of major buildings, streets, railroad tracks, etc., is the same now as it was at the time of the crime.

            Here is the account that Hughes gave of the crime at the trial.  Hughes testified that he drove to the crime scene with Harrington and the other alleged perpetrator, Curtis McGhee.  He said they parked the car at a certain place near the lot, Harrington took a shotgun out of his trunk and wrapped it in a jacket, then he saw Harrington and McGhee disappear around the corner onto the lot where they were going to steal a particular car. The victim was shot, not at that car lot, but on some railroad tracks about a block away, and the perpetrators had to cross the street to get to the place he was shot.  Ballistic evidence showed the direction from which he was shot, so I could determine from that and crime scene photos what was behind him when he was shot.  There was actually another car lot behind him when he was shot, with parked cars immediately behind him.  Hughes said that after he heard a shot, he saw Harrington and McGhee come running out from behind a particular building, up onto the street and over to the getaway car.  There was a large drainage ditch next to the road that the perpetrators had to get through to get to the getaway car. The car was parked next to some large trees, but McGhee did not say that at the trial.  Then, according to Hughes, they drove away.  He specified the parking place on an aerial photo, and named the streets they drove on.  I was able to determine from Hughes description and crime scene photos which way they would have had to drive the car immediately upon entering it to follow the route he specified, although he never said this explicitly at trial.

            There are several significant things here that never came up explicitly in the trial, but the perpetrators must have encountered to commit the crime.  Some of these things are easy to figure out if you have the crime scene photos and the testimony, and can actually walk around the crime scene and see what is the lay of the land, what is next to what, where the parts of the scene are in relation to each other and in relation to the photos, etc.

            For example, to get from the murder scene to the getaway car, Hughes testified that Harrington ran behind a specific building.  At that time, I was able to piece together from crime scene photos and visiting the crime scene that there were waist-high weeds and grass behind the building, but you couldn’t tell that from what you would have heard and seen at the trial.  So I asked Harrington, "Did you shoot Schweer?"

"No."

"Were you at the crime scene?"

"No."

" Did you run behind that building next to the tracks?"

"No."

"So you don't know what was behind the building?"

"No."

"You don't know whether it was cement and blacktop, sand and gravel, or weeds and grass?"

"No."

            Running from a murder scene in the dark, one could not fail to notice that one had to run through waist-high weeds and grass, which would have been a significant impediment.  He claimed not to know that.

            There were several major facts about the crime that the perpetrator knows but Harrington claimed not to know.  Another example is, the perpetrators had to cross the street to get from the car lot where the car was to be stolen to the scene of the shooting.  I asked Harrington,

"Do you know where the perpetrators had to go to get from the car that was to be stolen to the scene of the shooting?"

"No."

"Do you know if they had to go under an underpass, across the street, or over a bridge?"

"No."

            So Harrington was claiming not even to know where the perpetrators went to commit the crime. 

            To get to the getaway car, the perpetrators had to negotiate a deep drainage ditch.  Harrington claimed not to know what kind of obstacle they had to negotiate -- drainage ditch, wire fence, or concrete wall.

            He also claimed not to know what was behind the victim when he was shot (parked cars), or what the getaway car was parked next to (large trees), or what direction the car was driven initially for the getaway (straight ahead). (Hughes testified that Harrington drove the car.)

            Clearly, if Harrington committed the crime, this is information he would have.

QUESTION: This was 23 years ago. What if he has forgotten what happened that night?

DR. FARWELL:  We ran a second test to eliminate this possibility. Harrington had several alibi witnesses who testified that at the time of the crime he was in Omaha, not Council Bluffs, at a concert and later driving around town with friends.  I examined the transcripts and spoke to one of Harrington's major alibi witnesses, Mr. Karl Wright, who was his football coach at the time.  I found out details of the events of that same evening, as recounted by the alibi witnesses, events that took place far from the crime scene at the time of the crime.  I tested Harrington's brain for information relevant to the events of the evening, as recounted by the alibi witnesses.  For example, Harrington's football coach said he had a long conversation with Harrington that evening about football, and the fact that he had benched Harrington.  They met at a music concert where the football coach had gone to pick up his daughter. They sat on some white bricks near the gate to the concert at the time. 

Harrington's brain responses

QUESTION: What were Harrington's brain responses?

DR. FARWELL:  Please see Appendix 2, Figure 1: Harrington's Brain-Wave Responses to Crime-Scene Information. 

            These are plots of Harrington's brain responses.  To clarify the data and to isolate the data of interest, we have included only the time range from 600 to 1500 milliseconds (0.6 to 1.5 seconds) after the stimulus. (The full waveforms are included in the original report.)  Before this range, the subject has not yet recognized and processed the differences in meaning of the stimuli of different types, so the brain responses to the different stimulus types are the same.  After this time range, the response of interest is over.  So we're focusing on this time range.

QUESTION: What do Harrington's brain responses reveal?

DR. FARWELL:  First let's look at Figure 1, Harrington's Brain-Wave Responses to Crime Stimuli.  The red line is the response to the Targets.  This is the voltage across this time range at the parietal area of the scalp, a standard scalp site known as Pz, where the P300 is of maximum amplitude.  We can see that there is a positive peak here.  That's the P300.  This is followed by a negative deflection.  The two of these together constitute a MERMER.

QUESTION: So the MERMER includes the P300 plus a subsequent negative deflection?  Is that all?

Dr. FARWELL: There is more to it than that, but the additional scientific details have no bearing on this case, because I did not use them in the data analysis.  They are of scientific interest, but we can safely ignore them for the purposes of the findings on Harrington.  For those who are interested in the technicalities,  I am convinced that there are phasic changes in the frequency-domain brain response that do not appear in the time-domain averages, because they are not phase-locked to the stimulus.  I have some data to support that, and I maintain that this is a scientifically interesting and potentially important distinction. The negative deflection also has a different scalp distribution than the P300, with a prominent frontal component.  These distinctions are not, however, necessary for understanding what we measured in the Harrington case, and they were not included in the data analysis algorithm we applied to Harrington's data.  So, for the purposes of this discussion we can say that the MERMER contains the P300 positive peak and a subsequent negative deflection.  We can isolate our discussion and analysis to the P300 without changing in any way the scientific conclusions warranted by the data.  This allows us to remain within the realm of scientific phenomena that have been extensively tested, peer-reviewed, and published, are known to be accurately detectable, and are extremely well accepted in the scientific community. 

QUESTION: Why do we get a large P300 in response to the Targets?

DR. FARWELL: Because they are noteworthy to the subject.  Remember the elephant?  The subject knows these details about the crime, we have discussed them with him, and he is required to press a special button when they appear.  So he recognizes and takes note of them, and we get a P300.

QUESTION: What about the other brain responses?

DR. FARWELL: The green line represents the response to the Irrelevant stimuli.  These are things that are irrelevant to the crime and irrelevant to the subject.  They are items that would be equally plausible as details of the crime for a subject who did not know about the crime.  As you can see here, the Irrelevants do not produce a large P300, nor do they produce a MERMER.

QUESTION: What about the crime-relevant stimuli?

DR. FARWELL: Recall that the crime-relevant stimuli -- that is, the ones that the subject will know if he participated in the crime but has no way of knowing if he did not -- are called Probes.  The response to the Probes is represented by the blue line.  Note that with the crime stimuli, the response to the Probes is just like the response to the Irrelevants.  In the time range of interest, there are no significant peaks or troughs; there is no P300 and no MERMER.  This indicates that Harrington does not recognize the Probes as any different from the Irrelevants.  That is, his brain does not contain the relevant information about the crime. 

QUESTION: What about the alibi stimuli?

DR. FARWELL: See Appendix 2, Figure 2: Harrington's Brain-Wave Responses to Alibi Information. For the alibi stimuli, as with the crime stimuli, we get a large P300 and a large MERMER to the Targets.  Recall that these are things we know that he knows.  Also as before, we do not get a large P300 or a large MERMER to the Irrelevants. 

            Here, however, we do get a large P300 and a large MERMER to the Probes.  These are stimuli relevant to the alibi that we did not identify to Harrington during the test. 

QUESTION: So what does this show?

DR. FARWELL: The Probe stimuli contain information about the events of the evening of the crime, as described by Harrington's alibi witnesses, who placed him in a different city, at a concert and later driving around town with friends at the time of the crime.  For example, according to an alibi witness who was said he saw Harrington at the concert, he and Harrington sat on a white brick wall and talked about football during the concert.  "White bricks" and "football" were two of the Probes.

            Brain Fingerprinting showed that the information stored in Harrington's brain regarding the events of that evening matched the alibi, and did not match the crime scene. So Harrington did have a record of the evening of the murder stored in his brain.  It was a record of the events that he actually did participate in, according to alibi witnesses -- attending a concert with friends. It was not a record of the crime scene.

            The scientific fact here is that the record of the evening of the murder stored in Harrington's brain matches the alibi and does not match the crime.  This is essentially the same as if his fingerprints or DNA match the fingerprints or DNA at the scene of the alibi and not the fingerprints or DNA at the scene of the crime. How do we interpret that fact?  Well, one reasonable conclusion is that he was not at the crime scene, but rather was at a concert in another city with friends.  I'll discuss this in more detail later.

Data analysis and statistical confidence

QUESTION: How certain is this result?

DR. FARWELL:  You can clearly see the result here on the plots, but we don't go by visual examination, or by your impression or mine of the graphs.  We compare the brain responses mathematically, and come up with a mathematical determination of "information present" or "information absent" and a statistical confidence for this.  For the crime scene information, the determination was "information absent" -- the details of the crime were not stored in Harrington's brain.  For the alibi information, the determination was "information present" -- Harrington's brain did have a record of the events of his alibi stored in his brain.  The statistical confidence for this determination depends on how much data we include in the analysis.  When we include only the P300, we get a confidence of 99% for both determinations -- "information absent" regarding the crime, and "information present" regarding the alibi.   When we use the full MERMER, we get exactly the same results, but with a higher statistical confidence, 99.99% for both determinations.

            I analyzed the data using the MERMER, and I also analyzed the data using only the P300, just to be on the conservative side.  When I leave out all of the refinements, discoveries, and innovations I have come up with recently, and use only the most traditional, well-established scientific phenomenon in the entire field of cognitive psychophysiology over the last 35 years -- that is, the P300 -- I get exactly the same result, with a confidence of 99%.  Using the full MERMER doesn't change the results; it only gives us more data to work with so we get a higher statistical confidence.

QUESTION: How did you analyze the data?

DR. FARWELL: I have described the algorithms in detail in my publications and patents. (See Appendices 6 and 7 of the Report.) I used the same standard algorithms on the Harrington data as my colleagues and I used previously.  I used the statistical procedure of bootstrapping on the correlations between the Probe and Target waveforms, compared with the correlations between the Probe and Irrelevant waveforms.  Essentially, the question we are asking mathematically is, "Are the Probe brain responses like the Target responses or are the Probe responses like the Irrelevant responses?"  If the Probe responses are like the responses to the Targets, this indicates the subject recognizes the Probes as significant.  If the Probe responses are like the responses to the Irrelevants, this indicates that the subject does not recognize the Probes as being any different from the Irrelevants.

QUESTION: Is this the standard data-analysis procedure for this application?

DR. FARWELL: Yes.  It is the same procedure we used in Farwell and Donchin 1991 and Farwell and Smith 2001.  Essentially this same procedure has been used by Iacono as well. 

QUESTION: What is the difference between the P300 data analysis you conducted and the MERMER data analysis you conducted?

DR. FARWELL:  They are identical except for the time window.  In both cases I used bootstrapping on correlations.  For the P300, I used a time window from 600 to 1000 msec.  For the MERMER, I used 600 to 1600 msec.  The results I got are also identical, except that the MERMER gave a higher statistical confidence.

QUESTION: Why do we look at this time range, and not the early part of the brain response?

DR. FARWELL: There is a pattern to the response for the early period before this time range also, but it is not relevant to what we are measuring.  Initially, immediately after the stimulus, the brain is processing the stimulus at the sensory level.  We see event-related potentials here, but they are the same for all three stimulus types, Targets, Probes, and Irrelevants. This is because on a sensory level, these three types of stimuli are not different.  They cause the same sensory processing and the same exogenous or sensory event-related potentials.  A little later, the subject recognizes the cognitive meaning of the stimuli, and at this point he differentiates between the different stimulus types -- Targets, etc.. At this point cognitive or endogenous event-related potentials begin. 

            The brain responses for the different stimulus types diverge at the point where the subject begins processing the different cognitive meanings of the Target, Probe, and Irrelevant stimuli for the subject.  If we were studying sensory processing, the early event-related potentials would be of interest.  For our purposes, however, we are only interested in the cognitive event-related potentials that manifest information processing of the meaning of the stimuli.  That is why we isolate this time range in analyzing the brain responses.

Accuracy rate of Brain Fingerprinting Testing

QUESTION: Is the 99% or 99.99% confidence you yielded by your data analysis algorithm an accuracy rate?

DR. FARWELL: No. It is a statistical confidence for this specific result. It means, what is the mathematical probability that this is a genuine phenomenon, and did not just take place by chance?  What is the probability that these differences we see here on the graph are actually real? This is our statistical confidence for the result.  Accuracy rate is how often we get the correct result.

QUESTION: What has been the accuracy rate of Brain Fingerprinting in the past?

DR. FARWELL: The accuracy rate has been 100% in all the studies I have done.  Here we have to distinguish the different possible outcomes of a test.  The outcome can be one of three: information present, information absent, or indeterminate.  An indeterminate outcome means that the mathematical algorithm determines that we do not have enough data to make a clear determination.  In simple language, the outcomes are "this information is stored in the brain," "this information is not stored in the brain," and "no clear distinction can be made based on the available data."

            For the "information present" and "information absent" outcomes, they can in theory be either correct or incorrect.  In the work I have done, they have always been correct.  "Indeterminate" does not mean incorrect, it just means that the system could not make a clear determination, so it does not make either determination.

            Incorrect determinations can be of two types, false positives -- people who lack the crime-relevant knowledge falsely found to be "information present," -- and false negatives -- people who have the crime-relevant knowledge falsely found to be "information absent." My colleagues and I have never had either one of these.

            In the study we published originally in 1986, in the three CIA studies including the Navy study, and in the two FBI studies including the one in the Journal of Forensic Sciences, we made a definite determination in every case.  There were no indeterminates. 

            In the Farwell and Donchin study published in 1991, there were 12.5% indeterminates.  That is, we made a determination in 87.5% of the cases.  In every case where we made a determination, 100% of these determinations were correct.  There were no false positives and no false negatives.  So the system never made any inaccurate determinations, but there were 12.5% of the cases where no determination was made.

Standard technical and scientific procedures, techniques, and phenomena

QUESTION: Did you follow standard technical and scientific procedures for measuring brain waves in your test of Harrington?

DR. FARWELL: Yes.

QUESTION: Could you specify these standard technical and scientific procedures, techniques, and the relevant scientific phenomena?

DR. FARWELL: Yes.  Table 1 summarizes the basic standard technical and scientific procedures we used and phenomena we measured.  The experimental design features are described in more detail in the original report, along with a description of the most salient scientific and technical details.

Table 1

Scientific and Technical Procedures and Phenomena

1.      Measurement of electrical brain signals (electroencephalography or EEG) non-invasively from the scalp

2.      Signal averaging for detecting event-related brain potentials (ERPs)

3.      The International 10-20 System for electrode placement

4.      The P300 component of the event-related potential

5.      The measurement of P300 from Fz, Cz, and Pz scalp sites

6.      Analysis of P300 using data from the Pz scalp site where it is maximal

7.      The statistical technique of bootstrapping as described in Wasserman and Bockenholt 1989,  Farwell and Donchin 1991, and Efron 1979.

8.      Optimal digital filters as described in Farwell, Martinerie, Bashore, Rapp, and Goddard 1991 with a passband cutoff frequency of 6 Hz and a stopband cutoff frequency of 8 Hz

9.      Measurement of eye movements (EOG) through their electrical signals

10.  Artifact rejection of trials with EOG range greater than 117 microvolts

11. Grass P5 amps set to a gain of 50,000 for EEG, 10,000 for EOG, 0.1 Hz 1/2 amplitude low frequency analog filter, 30 Hz 1/2 amplitude high frequency analog filter, 60 Hz notch filter

12. Silver-silver chloride electrodes (disposable)

13. Linked ears as a reference

14.  Visually presented word stimuli consisting of short phrases for the elicitation of the event-related brain potentials

15.  Button-press responses with the left and right thumbs to different categories of stimuli

16.  A 400 msec stimulus duration for visually presented word stimuli consisting of multiple words in a phrase

17.  Blocks consisting of 72 trials each, averaging and analyzing across 24 blocks for the crime stimuli and 16 blocks for the alibi stimuli

18.  Presentation of visual word stimuli in a random sequence

19.  Digitizing rate of 100 Hz

20.  Digitizing with a Scientific Solutions AD signal processing board.

QUESTION: Are these procedures, techniques, and phenomena standard and accepted in the scientific community for cognitive psychophysiology?

DR. FARWELL: Yes.

QUESTION: Does this mean that all laboratories will use exactly the same procedures, parameters, and techniques?

DR. FARWELL:  No, not exactly. In any scientific field, the standard procedures are not a straight jacket, but provide a range and a set of guidelines for what will produce optimal results.  For many of these parameters, there is an acceptable or optimal range, and different scientists make choices within the range based on the specific experimental design, the scientific phenomena investigated, and personal preferences.   For example, in the Farwell et al. paper on Optimal Digital Filters for Long-Latency Event-Related Potentials published in Psychophysiology we conducted research on the best features and settings for the several parameters involved in a digital filters used to minimize noise in the data and increase the signal-to-noise ratio for data analysis.  We found that a range of parameters for digital and analog filters provided acceptable performance, and there are some tradeoffs with the different parameters depending on which features are important in a specific experimental design. I am not saying that every successful laboratory uses exactly the same parameters we use.  What I am saying is that we used parameters, procedures, phenomena, and techniques that are well known, well accepted, and within the range of what other respected, experienced, and successful laboratories in the field use. 

Dr. Farwell's research and results

QUESTION: Could you describe your scientific studies on Brain Fingerprinting, or detection of concealed information through the use of brain waves, and their results?

DR. FARWELL: Table 2 summarizes the studies and results my colleagues and I have conducted on this scientific phenomenon.  (Complete references are contained in the original report, in the references section of Appendix 6, Farwell and Smith 2001.) Note that the terminology used in the various studies varies.  Not all of these used the term "Brain Fingerprinting," but what is important is the phenomenon and not what name we may give to it.  Terminology tends to evolve over time, and this is no exception.

Table 2

Scientific Studies on Brain Fingerprinting by Farwell and Colleagues

Peer-reviewed publications

QUESTION: Which of these studies were published in peer-reviewed journals?

DR. FARWELL: The first publication was Farwell and Donchin in 1996, an abstract in Psychophysiology.  Farwell and Donchin 1988 and 1989, and Farwell 1992 were also abstracts in Psychophysiology.  Farwell and Donchin 1991 was published in Psychophysiology.   Farwell and Smith 2001, which I wrote with FBI agent and FBI Academy instructor Sharon Smith on research we did together, has been accepted for publication in the Journal of Forensic Sciences, and will be printed in January 2001.

QUESTION: What similar studies have been published by other scientists?

DR. FARWELL: Bill Iacono and his colleagues have published similar studies in Psychophysiology, Allen and Iacono 1997 and Allen, Iacono, and Danielson 1992.  Since Dr. Iacono will be testifying in the Harrington hearing, I will let him describe his own work.  Peter Rosenfeld and his colleagues have also published similar studies.

QUESTION: Were the CIA studies peer reviewed?

DR. FARWELL: Yes.  The CIA brought a group of experts from around the country together to peer review these studies.   I met with them at length, presented my research and results in detail, and answered all of their questions.

QUESTION: What was the result?

DR. FARWELL:  According to what the CIA told me both verbally and in writing, the research was found to be excellent in every respect.  I also met personally with the Director of the CIA, James Woolsey, and his response was highly favorable.   I got 100% accurate results, and you can’t do better than that. 

QUESTION: Has the CIA report on that peer review been publicly released?

DR. FARWELL: No.

QUESTION: Do you need approval from the CIA to publish the studies you did for with CIA funding?

DR. FARWELL: Yes.

QUESTION: Have you received it?

DR. FARWELL: No.

QUESTION: What is the rationale for CIA approval of publications?

DR. FARWELL: They are concerned with sensitive information and national security.  Recall that FBI scientist Dr. Drew Richardson and I proved that we can detect FBI agents with 100% accuracy.   Dr. Hernandez and I proved that we can detect Navy medical experts with 100% accuracy.  If we can detect an FBI agent or a Navy medical expert, we can detect a CIA agent, a KGB agent, or an SVR agent.  The national security implications are obvious.  If hostile intelligence agencies implemented Brain Fingerprinting before we had a chance to implement it in the US, they would be able to detect our agents, and we would not be able to detect theirs.

QUESTION: Does the CIA have this technology? Is the CIA using Brain Fingerprinting?

ALLEGED WITNESS: They have a version of the technology.  They have not said publicly what they are doing with it, if anything.

QUESTION:  Have you been asked by any foreign governments to implement Brain Fingerprinting in foreign countries?  Have you done so?

DR. FARWELL: I was approached by the former Soviet Union to implement the system there.  I communicated with the State Department and the other appropriate agencies in the US, and I declined.  I have also been approached by several other countries.  I have not implemented the system in any foreign countries.

QUESTION: Do you have plans to do so?

DR. FARWELL: Only insofar as it is consistent with our national interest.  I am currently negotiating with several countries who are our allies.

QUESTION: Was the FBI study you conducted with Dr. Richardson peer reviewed and accepted in final form for publication in a peer-reviewed journal?

DR. FARWELL: Yes.

QUESTION: Once a scientific paper has been accepted in final form in a peer-reviewed journal, is there any scientific or academic procedure that could stop its publication?

DR. FARWELL: No.  The decision of the editors, taking into account the peer reviewers' views, is final, and once reached it is irrevocable.   This is a major feature of the integrity of the peer-review process.

QUESTION: After the paper you and Richardson wrote on the FBI study was accepted in final form in a peer-reviewed journal, was it in fact published?

DR. FARWELL: No.

QUESTION: Why not?

DR. FARWELL: I am not at liberty to say.  This was several years ago.

QUESTION: What changes have taken place in national security concerns since you conducted the CIA, Navy, and FBI studies?

DR. FARWELL: For one thing, the cold war is over.  Also, our research has been replicated in other laboratories, so there really would be no way to keep a lid on it entirely.  My patents also disclose the technique in some detail.

QUESTION: Do you expect to receive approval from the CIA to publish your research in the future?

DR. FARWELL: Yes, I have reason to believe that I will receive it in the near future.

The Farwell and Donchin 1991 publication in Psychophysiology

QUESTION: Please describe the study you and Emanuel Donchin conducted and published in Psychophysiology in 1991.

DR. FARWELL: We used the same stimulus types as I used on Harrington and  the other studies described above, Targets, Probes, and Irrelevants.  The stimuli were short phrases flashed on a computer screen.  The technical details are also essentially the same as those I used on Harrington and described above.  (There are some minor differences, for example, we used a longer inter-stimulus interval for Harrington, the filter settings are slightly different, etc.)

            The experimental question we were investigating was whether we could detect whether or not a subject had information stored in his brain regarding an event, and on this basis detect whether or not he had participated in the event. We ran two experiments.  In experiment 1 we detected information regarding a mock crime.  In experiment 2 we detected information regarding actual minor crimes or socially undesirable acts.

            In Experiment 1, 20 subjects each were trained with an interactive computer program to carry out one of two different mock espionage crimes, and then each enacted the scenario he had been trained to enact.  Thus, for each subject we had one scenario he had enacted, and one scenario he had not enacted.

            We tested each of the 20 subjects on each of the two scenarios, the one which he had enacted and the one which he had not.  Recall that the Target stimuli are known to be relevant to the subject, whether he enacted the scenario being tested or not.  We make the Targets relevant by providing the subject with a list of the Targets and instructing him to push a special button whenever a Target appears, and another button when any other stimulus appears.  The Irrelevants are, as the name implies, irrelevant.  The Probes are relevant to the investigated event.  During the test, the subject is given no information as to which stimuli are Probes. 

            Thus, the Probes will be noteworthy for the subject if and only if he actually participated in the investigated event and consequently has the information regarding that event stored in his brain. The Irrelevants are structured so that they will be the same type of items as Probes, and equally plausible as details of the investigated event for a person who did not enact the event.  For example, if the mock espionage crime involved seeking out and approaching a contact who and commenting on his white shirt, a Probe could be "white shirt," and an Irrelevant could be "yellow tie."

            Our prediction regarding the brain-wave responses to the three types of stimuli was as follows:

1.      All subjects would display large P300s in response to the Target stimuli, since the Targets were noteworthy to all subjects.

2.      All subjects would not display large P300s in response to the Irrelevants, since they would not be noteworthy to the subjects.

3.      Each subject would display a large P300 to the Probe stimuli regarding the scenario he had enacted, and not to the Probe stimuli for the scenario he had not enacted.

            We had 20 subjects, then, each of whom had participated in one of two events.  We predicted large P300s in response to the Probe stimuli relevant to the event each subject had participated in, and not to the other event.

QUESTION: Were these predictions borne out by the data?

DR. FARWELL: Yes.  All of the determinations we made were accurate.  In 35 of the 40 cases, our data analysis algorithm yielded a definite determination of "information present" or "information absent."  All of these determinations not only were correct, but also had a high statistical confidence.  The remaining five cases had a determination of "indeterminate," that is, we we had insufficient information to make a definite determination in either direction.

QUESTION: Please describe the experiment you did on actual crimes and published in Farwell and Donchin 1991.

DR.  FARWELL:  We tested four subjects who had committed a minor crime or socially undesirable act (e.g., getting caught for underage drinking).  As in experiment 1, we tested each subject for one act he/she had committed, and one he/she had not. 

            As Donchin and I stated in the published paper, ""The results of experiment 1 clearly show the effectiveness of this paradigm in detecting guilty knowledge regarding a mock crime.  The purpose of experiment 2 was to examine the feasibility of system in detecting guilty knowledge regarding actual crimes, which were not committed as part of a laboratory study and may have taken place a considerable time prior to the testing situation." 

            We concluded that "As in Experiment 1, the system proved highly reliable in distinguishing between the presence and the absence of guilty knowledge."

            We suggested that further research was needed, and noted, "..we note that because the P300 is used here as an index of a cognitive rather than an affective activity, it is considerably less reasonable to discount laboratory demonstrations.  It would seem…that as the overall significance of the test increases in real-life…the technique's effectiveness will increase rather than decrease." 

QUESTION: Did you go on to conduct additional research?

DR. FARWELL: Yes, in the subsequent studies for the CIA, Navy, and FBI, as you can see in the table, we ran over 100 more subjects.  In most of these cases, including both FBI experiments and two of the three CIA experiments, we were testing for information regarding real-life events, not information obtained in a mock crime or laboratory situation.  The system proved 100% accurate in all of the subsequent studies, with no incorrect determinations and no indeterminates.

QUESTION: Compare the procedures you published in the Farwell and Donchin 1991 studies to the Harrington case.

DR. FARWELL: In the Harrington case, as with the two Farwell and Donchin studies, we had a person who had participated in one of two events. For experiment 1, the events were a mock crime scenario the subject had enacted and one he had not.  For experiment 2, the events were an actual minor crime or socially undesirable act that each subject had committed and another act that he/she had not.  For Harrington, the two events were the crime and the alibi.  This is almost the identical situation to what we tested in experiment 2, and similar to what we tested in experiment 1.

            We ran two tests on Harrington, one with Probes relevant to the crime, and one with Probes relevant to the alibi.  As with the previous studies, the well established existing science leads to the prediction that we will detect a large P300 in response to the Probes relevant to the event Harrington participated in, and not in response to the Probes relevant to the event Harrington did not participate in.  What we found in the Harrington case was exactly this: a large P300 in response to the Probes relevant to the alibi, and not to the Probes relevant to the crime.  This is what we would predict in the situation where Harrington participated in the alibi and not in the crime.  (The predictions of a large P300 to Targets and not to Irrelevants were also borne out in the Harrington case.)

QUESTION: So the experimental design was essentially the same, at least in experiment 2, and very similar in experiment 1, to the Harrington test.  Could you elaborate on the comparison between the Harrington test and earlier tests?

DR. FARWELL:  I wrote the computer software for both data acquisition and data analysis in the Farwell and Donchin research.  I ran the subjects, collected the data, and analyzed the data. We designed the study and wrote the paper together.  I used the same mathematical data analysis algorithm for Harrington as we had used in the studies with Donchin.  This was a well established statistical procedure known as bootstrapping on the correlations between the respective pairs of trial types.  It is described in the publications (see Appendix 6 of the Report).  We also used essentially the same technical procedures, such as digitizing and analog and digital filtering.

            In the previous studies, we knew in advance which of the two events each subject had participated in, and the results bore out our predictions regarding the brain responses: Probe responses were similar to Target responses (i.e., contained a P300) only for the event each subject had participated in.

            In the Harrington case, the Probe responses were similar to the Target responses (i.e., contained a P300) for the alibi, but not for the crime. This provides evidence that Harrington did not have the details of the crime stored in his brain, but did have the details of the alibi stored in his brain.

            The essential difference between the Harrington case and experiment 2 of Farwell and Donchin (as well as the real-life CIA experiment and the real-life FBI experiment published by Farwell and Smith), is that in the other studies we knew in advance what the correct outcome was.  That is, we knew independently who had participated in what events.  Our data analysis came to the correct conclusion in every case where a conclusion was reached.  These experiments served as a test of our system's ability to reach the correct conclusion regarding participation in real-life events. 

            In the Harrington case, we did not know before running the test whether Harrington had participated in the crime or in the events of his alibi.  The purpose of this application was to determine scientifically what information was stored in Harrington's brain, as a means to shed some light on what events he had participated in.  In other words, in testing Harrington we did essentially the same thing as we did in previous real-life studies, including experiment 2 of Farwell and Donchin 1991, but for the purpose of shedding some light on unknown real-life activities, rather than testing our system on known real-life activities.  The previous real-life studies established the reliability of the system in detecting information regarding real-life events, and the Harrington case applied this same algorithm to real-life events that had forensic significance.

QUESTION: Compare the data analysis, results, and conclusions in the Harrington test with those of the previous Farwell and Donchin study.

DR. FARWELL:  In the Harrington case, we analyzed the data twice, once with a time window including only the P300 (600 - 1000 msec) and once with a larger time window including the full MERMER (600-1600 msec). The first of these two analyses was the same algorithm as we used in the Farwell and Donchin study.              For both the crime and alibi tests for Harrington, the result came out with a strong statistical confidence, 99% for the P300 analysis and 99.99% for the MERMER analysis.  In other words, when we follow the methods of the Farwell and Donchin study, the CIA real-life study, and the FBI real-life study, and analyze the data in the same way, the scientific conclusion we reach regarding Harrington is that he does not have the specific details of the crime stored in his brain, and does have the details of the alibi stored in his brain.  The significance of this is discussed below.

Application in real-life events

QUESTION: How do the results obtained in the laboratory apply in the field?

DR. FARWELL:  The important distinction here is not whether the sign on the door where the brain-wave measurements take place says "laboratory" or not.  What is important is what we are measuring and how we are measuring it. Several of the studies -- including experiment 2 of Farwell and Donchin, one of the CIA studies and the one Sharon Smith of the FBI and I are currently publishing in the Journal of Forensic Sciences -- detected information stored in the brain regarding real-life events in the lives of people, events that happened in the real world outside the realm of any laboratory manipulation or experimental control.  The FBI study I conducted with Dr. Richardson and the Navy study I conducted with Dr. Hernandez also detected real-life information that was not accumulated by the subjects in a laboratory.

            In any case, what we have proven is that Brain Fingerprinting is an effective means to detect the presence or absence of information stored in the brain.  Scientifically, information stored in the brain is information stored in the brain, whether it is relevant to a crime or to some other event.  The fact that the EEG amplifiers and computers are sitting in a prison meeting room rather than in a room with a sign that says "laboratory" on the door does not change the scientific procedures or their results.

            When a DNA expert first went into court and testified that there was less than one chance in a million that the biological samples taken in a rape or murder case did not match the DNA from the suspect, this did not mean that they had collected blood or semen from one million rape or murder victims and matched it with the perpetrators.  DNA is DNA, whether it is collected at a crime scene or elsewhere.  It's more difficult and complicated collecting DNA at a crime scene than in the laboratory, of course.  For example, I have heard of a rape/murder case where there was DNA from four different people was found on the victim, and one of the tests as to whether it matched a suspect was indeterminate.  This doesn't tend to happen in the laboratory.  Nevertheless, with DNA and other kinds of scientific evidence, the scientific results of non-forensic laboratory tests are held to be applicable in forensic settings in detecting the same phenomenon, and they hold up in court when the samples are not collected in a laboratory.

            Just as DNA is DNA, information stored in the brain is information stored in the brain.  That's what we detect. Remember, we're not detecting guilt or innocence of a crime, we're detecting presence or absence of information in the brain -- and again, several of the previous studies detected information regarding real-life events in peoples' lives.  DNA is DNA, whether it's involved in a crime or not, and information regarding a real-life event is information regarding a real-life event, whether that event is a crime or not.   What we detect scientifically is the presence or absence of information stored in the brain.  What bearing this may have on a crime is a separate question, and that involves how the scientific results are interpreted, evaluated, and weighed.

Value of the scientific results in the Harrington case

QUESTION: Did Brain Fingerprinting prove that Harrington is innocent, or not guilty?

DR. FARWELL: What Brain Fingerprinting tests scientifically is whether or not specific information is stored in the brain.  That is what the scientific result of "information present" or "information absent" means.   Brain Fingerprinting detects the presence or absence of information, not guilt or innocence per se.  It is up to a judge or jury to determine Harrington's guilt or innocence, based on the evidence provided by Brain Fingerprinting, along with all the other relevant evidence presented at the trial.   Brain Fingerprinting is a scientific technique, and the results it provides are scientific results.  "Innocent" and "guilty" are legal terms. 

            Brain Fingerprinting establishes scientifically the presence or absence of certain information stored in the brain. In Harrington's case, Brain Fingerprinting demonstrated that the record of the events of the night of the murder stored in Harrington's brain matches Harrington's alibi and does not match the crime scene. 

            It's as if we found a match between the DNA of a suspect and the DNA found at the scene of the alibi, and did not find a match between the DNA of a suspect and the DNA found at the crime scene.  Does that prove absolutely that the subject is innocent?  Not necessarily.  There may be many different explanations for why the subject's biological samples do or don't match what was found at the crime scene in terms of DNA.  Is this relevant and useful information to be used in determining the truth about the situation?  Yes.  What the scientific test can do is to determine whether there is a match between something on the person of the suspect and the evidence from the crime scene.

            This is what Brain Fingerprinting does scientifically.  Just as DNA testing matches biological samples from the crime scene with biological samples on the person of the suspect, and fingerprinting matches fingerprints from the crime scene with the fingerprints on the fingers of the suspect, Brain Fingerprinting matches informational evidence from the crime scene with information stored in the brain of the suspect -- or, as in the case of Harrington, shows that the information stored in the brain does not match the crime scene.  In Harrington's case, Brain Fingerprinting determined that specific information relevant to the crime was not stored in Harrington's brain, and details of the events of the alibi were stored in Harrington's brain.  In other words, the record of the evening of the crime stored in Harrington's brain matched the alibi and not the crime.

QUESTION: What is the value of the results of the Brain Fingerprinting test on Harrington?  What bearing do these results have on the case?

DR. FARWELL:  What we proved scientifically was that certain specific details about the crime were not stored in Harrington's brain.  To get this in perspective, let's turn it around.  Say we had a witness who said that he had seen the whole crime, and had run right along with the perpetrators.  In our hypothetical example, let's say he also attended the trial.  Let' suppose he claimed that the crime was just as Hughes described it at the trial. (Hughes has recanted, and now states that he fabricated this entire story, but when Harrington was convicted that was not known.)  We could question the alleged witness/participant in the following manner:

Question: "Did you attend the trial?"

Alleged witness: "Yes."

Question: "So you know the details about the crime that were revealed or testified to at the trial."

Alleged witness: "Yes.

Question: "Let’s just review some of these details that came up at the trial, to see if you remember them."

Alleged witness: "OK."

            Note: The following items were known to Harrington from the trial, and were used as Target (not Probe) stimuli in the Brain Fingerprinting test on him.  We could question our hypothetical alleged witness as follows:

Question: "Who was a person who allegedly rode in the car and stayed at the car during the crime?"

Alleged witness: "Kevin Hughes."

Question: "Who was a person who allegedly participated in the crime?"

Alleged witness: "Curtis McGhee."

Question: "What was the business where the crime took place?"

Alleged witness: "McIntyre Oldsmobile."

Question: "What was the murder weapon?"

Alleged witness: "12 -gauge shotgun."

Question: "What was the murder weapon allegedly concealed in?"

Alleged witness: "Leather jacket."

Question: "What kind of job did the victim of the crime have?"

Alleged witness: "Security guard."

Question: "OK, you know the details of the crime that were testified to at the trial.  But you know more than that, don't you, because you participated in the whole crime.  You actually know what happened, not just the details that were revealed at trial, right?"

Alleged witness: "Yes."

Question: "Did you see the whole crime? Did you participate from start to finish?"

Alleged witness: "Yes, I was there.  I participated in the whole thing, right along with the perpetrators."

Question: "OK, now I'm going to see if you know the details of the crime that did NOT come out at the trial.  If you were actually there, you'll know these details, as well as the details you heard at the trial."

Alleged witness: "OK."

            Note: In all of the following questions regarding details of the crime that did not come out at the trial, the correct detail about the crime is the first of the three items mentioned.  These were the Probe stimuli used the Harrington Brain Fingerprinting test. The other two options were the Irrelevant stimuli in each case.   We could question our hypothetical alleged witness as follows:

Question: "So you accompanied Harrington and McGhee when they left the getaway car and headed onto the lot to steal the new car, as testified by Hughes."

Alleged witness: "Yes."

Question: "The murder did not take place on that lot, though.  When you left that lot and proceeded to the murder scene, where did you go?  Where did the perpetrator have to go to get from the car that was to be stolen to where the shooting took place?"

Alleged witness: "I don't know."

Question: "Did you go across a street, over a bridge, or under an underpass?"

Alleged witness: "I don't know."

Question. "When you got to the scene of the murder and saw the victim being shot, where was he?  What was he standing in front of? What was behind the victim when he was shot?"

Alleged witness: "I don't know."

Question: "Was it parked cars, a gas station, or a junkyard?"

Alleged witness: "I don't know."

Question: "After the shooting, according to Hughes' testimony, you ran behind a building back towards the getaway car.  Do you know what was behind the building?  Was it difficult running back there in the dark?  Did you have to struggle through waist-high weeds and grass, or was it  easy going?  What was on the ground the perpetrator ran over after he shot the victim and ran behind the building back towards the car?"

Alleged witness: "I don't know."

Question: "Was it weeds and grass, sand and gravel, or cement and blacktop?"

Alleged witness: "I don't know."

Question: "If you were at the scene, you know that before you could get to the getaway car, you had to negotiate a major obstacle.  What was the obstacle that the perpetrator had to get across to get to the road where the getaway car was parked?"

Alleged witness: "I don't know."

Question: "Was it a drainage ditch, a wire fence, or a concrete wall?"

Alleged witness: "I don't know."

Question: "Then you returned to the getaway car.  Where was it?  What was the getaway car parked next to?"

Alleged witness: "I don't know."

Question: "Was it by trees, behind a restaurant, or near a field?"

Alleged witness: "I don't know."

Question: "Then you drove off in the getaway car.  What direction did the perpetrator drive the car immediately after the shooting?"

Alleged witness: "I don't know."

Question: "Did you go straight ahead, turn around, or back up?"

Alleged witness: "I don't know."

            If you were the trier of fact, would you find it useful to know that the alleged witness did not know these details about the crime?

            If an alleged witness answered these questions in this way, we have a person who clearly knows the details of the crime that came out at the trial, and does not know the details of the crime that would have been experienced only by a perpetrator or accompanying witness.

            If we had questioned a person and he had responded in this way, would his lack of knowledge regarding the details of the crime be relevant information in the determination of whether or not he actually was present at the crime scene and participated in the crime?  I would submit that the answer is yes.  Do these answers prove absolutely that the alleged witness could not possibly have participated in the crime?  No.  Are they nevertheless relevant information for the trier of fact, which could be useful when evaluated along with other evidence?  I submit that the answer is yes.

            This is exactly what we have shown in the case of Harrington.   The above answers are how a person would answer who had only the information stored in his brain that Harrington has.  What Harrington's brain responses demonstrate is that Harrington knows only the details of the crime that came out at the trial, and not the details of the crime that would have been experienced only by a perpetrator. 

            Harrington's brain responses also provide strong evidence that the details of the events of the evening of the crime -- as recounted by his alibi witnesses, who placed him elsewhere at the time of the crime --  are stored in Harrington's brain.  The fact that Harrington's brain clearly does contain a record of the actual events that he participated in that night according to alibi witnesses  -- that is, the events of the alibi -- provides further evidence that Harrington's lack of knowledge regarding the details of the crime does not come from forgetfulness of what happened on that night. 

            Harrington's brain results demonstrate that Harrington has a lack of knowledge of significant details of the crime (details that did not come out at trial), combined with knowledge of details of the crime that did come out at trial, as well as knowledge of details of the events of the evening in question as described by his alibi witnesses.

            Does Harrington's demonstrated lack of knowledge of significant details of the crime constitute relevant evidence that would assist the trier of fact?  I submit that the answer is yes, just as it would be for an alleged witness as we described in the above example.  Does Brain Fingerprinting prove guilt or innocence absolutely, thus making other evidence irrelevant?  No. Brain Fingerprinting demonstrates the presence or absence of specific information, not guilt or innocence.  Does Brain Fingerprinting nevertheless provide useful evidence that, along with other evidence, can assist the trier of fact in his task of determining the truth?  I submit that the answer is yes.

Appendix 1

Differences between Brain Fingerprinting and Lie Detection or Psychophysiological Detection of Deception (PDD) Polygraphy

            The question often arises, "What does Brain Fingerprinting have to do with lie detection?"  The answer is that Brain Fingerprinting has absolutely nothing to do with lie detection.  Brain Fingerprinting detects information stored in the brain.  The results are exactly the same whether the person lies or tells the truth about this information or any other subject.  If a person's fingerprints or DNA match (or don't match) the fingerprints or DNA at a crime scene, this fact does not change in any way if the person lies or tells the truth about it.  The same is true of Brain Fingerprinting.  All it detects is the presence or absence of information, and this is completely independent of the process of lying or telling the truth.  Lying or telling the truth in no way affects the outcome of a Brain Fingerprinting test.  Brain Fingerprinting detects information, not lying.

            Another common question is, "What does Brain Fingerprinting have to do with polygraphy?" If by "polygraphy" one means lie detection, the answer is "Absolutely nothing."  The use of the word "polygraphy" to refer exclusively to lie detection, however, is an improper and confusing used of the original word.  The dictionary definition of a polygraph is "an instrument for recording variations of several different pulsations (as of physiological variables) simultaneously."  By the original denotation, polygraphy includes all psychophysiological research and measurement that includes more than one data channel.  This will include all of electroencephalography, any kind of brain-wave (EEG) measurements, cardiovascular measurements (both blood pressure and EKG) when they involve more than one data channel, and virtually everything else in the field of psychophysiology, from heart rate to reaction time to eye movements, whenever more than one isolated measurement is taken.  With this definition of polygraph, to ask "Is this polygraphy?" is the same as asking "Does this involve measuring more than one thing at a time?"  This is not a meaningful distinction for comparing and contrasting techniques on the field of psychophysiology, because it includes the whole field of psychophysiology plus a host of other scientific and non-scientific practices outside the field.

            In common language, "polygraph" is sometimes used to refer specifically and exclusively to a particular instrument designed for use in lie detection, and "polygraphy" is sometimes used as a synonym for "lie detection."   This is not really a correct use of the word.  The more correct and preferred term for practitioners of the art of lie detection is "detection of deception," or "psychophysiological detection of deception," or sometimes "credibility assessment." These terms more accurately describe the practice. 

            With the language thus clarified, the question becomes, "Is Brain Fingerprinting at all similar to psychophysiological detection of deception?"  The answer is "No, not in the least." 

            The two technologies have virtually nothing in common.  In Brain Fingerprinting, we detect information stored in the brain.  In psychophysiological detection of deception, what one seeks to detect is deception.  Having or not having certain information stored in the brain is entirely independent from lying about it or telling the truth about it.  No questions are asked and no answers are given during Brain Fingerprinting. The subject neither lies nor tells the truth at any time during the Brain Fingerprinting test.  The results of the Brain Fingerprinting test are exactly the same whether the subject has lied or told the truth at any time about any subject. 

            In our early paper on the subject (Farwell and Donchin 1991) we put the term "lie detection" in quotation marks because it is a term that can be misleading and does not apply to the scientific procedure we used to detect information. 

Brain Fingerprinting has virtually nothing in common with lie detection or psychophysiological detection of concealed information.  Granted, there is one way in which all forensic science and investigative techniques are similar, and that is that all of them are attempting to determine the truth about the situation and ultimately to distinguish guilty from innocent suspects.  Brain Fingerprinting and PDD polygraphy do have this in common; but they also have this in common with all other forensic technologies.  Superficially, Brain Fingerprinting testing may appear to be similar to PDD polygraphy in that in both procedures subjects are sitting while ongoing biological data are being collected.  When we consider what data are being collected, in what context, and for what purpose, however, it becomes clear that the techniques are fundamentally and dramatically different.

Please consider the following.  In determining whether two techniques are similar, one can consider three fundamental factors: 1)  What broad class of investigative activities the technique supports; 2) What specifically the technique is attempting to determine or detect; and 3) What measurements are taken to make the determination. 

            We will consider the similarity or difference between Brain Fingerprinting and PDD polygraphy from these three perspectives.  First of all, there are two very broad categories of investigative activities: A) those that involve taking testimony from people, and B) those that involve collecting evidence associated with the crime and attempting to match it with evidence associated with the perpetrator.  Testimony can be taken either from suspects or from non-suspects (e.g., witnesses and victims).  Whenever investigators are gathering testimony, the question of the veracity of the sources is an issue.  The field of detection of deception, of which PDD polygraphy is a part, addresses this issue.  Fundamentally, the field of detection of deception attempts to serve the process of questioning or interrogation by attempting to determine if the reports given are truthful.

            Within the broad class of investigative activities that seek to match evidence associated with the crime with evidence associated with the perpetrator, there are techniques that collect evidence indirectly associated with the suspect (e.g., matching tire tracks at the crime scene with the tires of the suspect’s car) and techniques that match evidence from the crime scene with evidence directly on the person of the perpetrator.  DNA, fingerprinting, and Brain Fingerprinting all fall into this latter subcategory. What Brain Fingerprinting does is to match evidence associated with the crime with evidence in the brain of the perpetrator.  This has nothing to do with the process of collecting testimony, with questioning, or with interrogation, the realms where PDD polygraphy has its application.  Polygraphy and Brain Fingerprinting serve two fundamentally different categories of investigative activities.

With respect to what the technique is specifically attempting to determine or detect, PDD polygraphy – as well as all other techniques for detection of deception such as voice stress analysis – is attempting to detect deception.  Brain Fingerprinting is attempting to determine whether or not certain information, in some cases information relevant to a crime, is stored in a person’s brain.  The results of a Brain Fingerprinting test are exactly the same whether the person is telling the truth or lying.  Brain Fingerprinting has this factor in common with other techniques for matching evidence from the crime scene with evidence on the person of the suspect, such as fingerprinting and DNA analysis. 

Whether a person has committed a crime or participated in another situation under investigation is entirely independent from whether he is lying about it.  With respect to these two parameters, there are four possibilities, as outlined in the below table.

            Brain Fingerprinting, DNA tests, fingerprinting, and all other techniques for matching evidence on the person of the suspect with evidence from the crime, if they are accurate, will have positive results (“information present”) for all subjects who committed the crime, whatever the subjects say about it.  The results will be the same for subjects whose verbal report is a false denial and for those whose verbal report is a true confession.

            Similarly, Brain Fingerprinting and all other evidence-matching techniques will, if accurate, produce a negative result (“information absent”) for all suspects who did not commit the crime, whatever their verbal reports.  The results will be the same for subjects whose verbal report is a true denial and for those whose verbal report is a false confession.

            The PDD polygraphy will, if accurate, will produce a substantially different pattern of results.  Unlike Brain Fingerprinting and other evidence-matching techniques, whether an accurate PDD polygraphy test produces a positive (“deception indicated”) or a negative (“no deception indicated”) result will depend not on whether or not the subject committed the crime, but on whether or not he tells the truth about it. An  accurate PDD polygraphy test result on a subject who committed the crime will be positive (“deception indicated”) if he lies about it and negative (“no deception indicated”) if he tells the truth.  An accurate PDD polygraphy result on a person who did not commit the crime will be negative if he tells the truth (that is, issues a true denial) and positive if he lies (a false confession).  The pattern of results for accurate Brain Fingerprinting and PDD polygraphy tests in these situations is presented below.

            In two of the four cases, Brain Fingerprinting and PDD polygraphy will produce opposite results if both are accurate.  Clearly, Brain Fingerprinting and PDD polygraphy are detecting or determining different things.

            Now let us turn to the question of what measurements are made in the service of this determination.  Brain Fingerprinting measures electrical voltage patterns at the scalp.  These voltage patterns are produced by specific information-processing brain activities. These information-processing brain activities take place independently of whether or not the subject is in an emotionally aroused state or a physically aroused state, and independently of any question of veracity on the part of the subject.

PDD polygraphy conventionally measures patterns expansion of the chest and abdomen, pressure in a cuff on the arm, and conductance of an electrical current on the palm.  Changes in these patterns indicate physical arousal, which, according to the underlying theory, is brought about by emotional arousal during interrogation, which in turn is brought about by lying. 

Clearly, Brain Fingerprinting and conventional PDD polygraphy measure two entirely different, non-intersecting, unrelated sets of physiological processes.  In this way also, the techniques are fundamentally different.

            Note also that during a Brain Fingerprinting test, no questions are asked or answered.  The subject neither lies nor tells the truth during the test, and the results of the Brain Fingerprinting test are the same whether the subject has lied or told the truth at any time.  With a PDD polygraphy or any other technology for the detection of deception, by contrast, the entire goal of the technology is to determine whether someone is lying or telling the truth, and the means to achieve this goal are measurements of physiological parameters held to be indicators of deception.