Report to the Honorable

Charles E. Grassley, U.S. Senate

United States General Accounting Office

GAO

October 2001 INVESTIGATIVE

TECHNIQUES

Federal Agency Views

on the Potential

Application of "Brain

Fingerprinting"

GAO-02-22
Page i GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

Letter 1

Results in Brief 1

Scope and Methodology 3

Background 4

How Brain Fingerprinting Is Intended to Work 6

Federal Agency Views on Brain Fingerprinting’s Potential

Application 8

Agency Comments and Our Evaluation 12

Appendix I Scientists’ Views on the Brain Fingerprinting

 Technique 14

Appendix II Comments From the U.S. Secret Service 20

Appendix III Comments From the Federal Bureau of Investigation 22

Abbreviations

CIA Central Intelligence Agency

DOD Department of Defense

EEG Electroencephalograph

FBI Federal Bureau of Investigation

MERMER Memory and Encoding Related Multifaceted

Electroencephalographic Response

NIH National Institutes of Health

Contents
Page 1 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

October 31, 2001

The Honorable Charles E. Grassley

United States Senate

Dear Senator Grassley:

Federal law enforcement and intelligence agencies use various techniques

to assist them in criminal investigations and intelligence efforts and seek

to identify new techniques to enhance their arsenal of investigative tools.

You requested that we review a technique that has been proposed for use

in the federal law enforcement and intelligence arenas, referred to as

“Brain Fingerprinting.” Its developer, Lawrence A. Farwell, Ph.D., has

indicated that Brain Fingerprinting can be used as an investigative tool,

with applications for law enforcement functions and intelligence

operations. Specifically, the technique is designed to determine whether

an individual recognizes certain details of an event or activity by

measuring the individual’s brain wave responses. In the past few years,

several federal agencies—including the Central Intelligence Agency (CIA),

Department of Defense (DOD), Federal Bureau of Investigation (FBI), and

the Secret Service—have interacted, to varying degrees, with the

developer to fund research or explore the technique for possible use in

law enforcement or intelligence operations.

This report provides information on how Brain Fingerprinting is intended

to work and federal agency views on its potential application. To obtain

information on Brain Fingerprinting, we interviewed the developer,

selected federal agency officials and three scientists in the field of

psychophysiology,1

 who were familiar with the technique. Although our

review did not constitute a technical analysis of Brain Fingerprinting, we

provide the views of those three scientists in appendix I.

Brain Fingerprinting is a proposed investigative technique that

incorporates the use of a test administered to a subject that consists of

specific information related to a particular event or activity. According to

its developer, the technique requires a sufficient amount of specific

 1

Refers to a branch of psychology that studies the interactions between physical or

chemical processes in the body and mental states or behavior.

United States General Accounting Office

Washington, DC 20548

Results in Brief
Page 2 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

information about the event or activity that would be known only to the

perpetrator and the investigator. The developer has indicated, therefore,

that Brain Fingerprinting is not designed as a screening tool—a function

that involves questioning a subject about events unknown to the

investigator. In administering the Brain Fingerprinting test, a subject is

shown a sequence of various stimuli on a computer screen in the form of

words, phrases, or pictures—some that are related to the event or activity

and others that are irrelevant. An electroencephalograph (EEG)2 records

the subject’s electrical brain activity, which appears as a waveform. The

technique employs a statistical method to analyze the components of the

waveform to determine whether or not the subject recognizes the

information. According to the developer, an investigator would be able to

use this information as evidence for or against a suspect. For example, the

developer has indicated that the technique could be used to determine

whether a suspect has knowledge of details about a crime.

Officials representing CIA, DOD, Secret Service, and FBI do not foresee

using the Brain Fingerprinting technique for their operations because of its

limited application. For example, CIA and DOD officials indicated that

their counterintelligence operations and criminal investigations do not

usually lend themselves to a technique such as Brain Fingerprinting

because use of the technique requires a unique level of detail and

information that would be known only to the perpetrator and the

investigators. These officials indicated that they need a tool to screen

current and prospective employees, which as indicated above, involves

questioning a subject about events unknown to the investigator. Further, a

Secret Service official indicated that the agency has had a high success

rate with the polygraph as an interrogative and screening tool and

therefore saw limited use for Brain Fingerprinting. FBI Laboratory

Division officials evaluated the technique in 1993 and 1999 and concluded

that Brain Fingerprinting had limited applicability and usefulness in FBI

investigations and personnel security and screening matters. In addition,

the division concluded, among other things, that, given the technique’s

limitations, the research expenses, equipment, and training costs were

perceived to exceed benefits. However, two FBI agents who collaborated

 2

An EEG records electrical activity of the brain from electrodes placed on the surface of

the scalp.
Page 3 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

with the developer on related research3 believe that Brain Fingerprinting

has potential as an investigative tool. One of these agents stated that use of

the technique would require a shift in FBI’s investigative and training

methods—a policy issue that would have to be addressed by FBI

management. Furthermore, the three scientists we interviewed expressed

a need for more research to demonstrate Brain Fingerprinting’s

application as an investigative tool.

In providing comments on a draft of this report, CIA, DOD, Secret Service,

and FBI generally agreed with the report and our presentation of their

views. (Written comments from the Secret Service and FBI are reprinted

in appendixes II and III). In addition, the developer of the technique, Dr.

Farwell, indicated that he had no comments or technical corrections on

the report.

As part of our data gathering efforts, we identified knowledgeable officials

from selected federal intelligence and law enforcement agencies that had

provided research funding for the Brain Fingerprinting technique, had

explored use of the technique, or had engaged in related or direct

research. Specifically, we spoke with officials at CIA; components of DOD,

which included the DOD Polygraph Institute, National Security Agency,

Defense Security Service, Army Criminal Investigation Command, Air

Force Surgeon General’s Office, and the Office of the Assistant Secretary

of Defense for Command, Control, Communications, and Intelligence; FBI;

and Secret Service. At DOD, our substantive contact focused on officials

from the DOD Polygraph Institute and Defense Security Service. For their

collective views, we refer to these components as “DOD.” Otherwise, we

refer to them by their individual name. At FBI, we spoke with officials who

had been involved in an evaluation of the Brain Fingerprinting technique.

We also spoke with two FBI agents who had collaborated with the

developer on related research. We interviewed these individuals because

they had first-hand knowledge of the Brain Fingerprinting technique and

experience with FBI investigative procedures. In addition, we reviewed

and analyzed documents provided by those agencies that relate to Brain

Fingerprinting and various forensic applications.

 3

Specifically, one of these agents conducted a graduate school research project with the

assistance of the developer. This agent indicated that her views regarding the technique

should therefore not be considered an endorsement by the FBI. The second agent indicated

that the research that he conducted with the developer had been requested and approved

by the FBI in 1992.

Scope and

Methodology
Page 4 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

To gain an understanding of the science underlying Brain Fingerprinting,

we interviewed researchers at the National Institutes of Health (NIH),

three scientists in the field of psychophysiology, and the developer of the

technique. We selected these scientists on the basis of recommendations

made by the agency officials we interviewed, researchers we spoke with at

NIH, and the developer. In addition, two of the scientists we spoke with

had testified in Harrington v. Iowa, the one court case we have identified

that has addressed Brain Fingerprinting evidence.4 In providing their

views, these scientists helped us understand the underlying methods of

Brain Fingerprinting and its potential application as an investigative tool.

We have included a summary of their views in appendix I of this report.

Their views are not meant in any way to represent the views of the

scientific community as a whole.

Furthermore, as part of our research efforts, we identified and reviewed

available documentation, including articles, studies, reports, and other

relevant materials in the related fields of psychophysiology, neuroscience,

and forensics. Our search for information related to Brain Fingerprinting

revealed that only a limited amount of independent documentation exists

about the technique and its uses for law enforcement and intelligence. We

also reviewed court documents in Harrington v. Iowa and interviewed the

prosecuting attorney in the case.

We did not perform a technical analysis of Brain Fingerprinting. That is,

we did not independently assess the hardware, software, or other

components of the technology nor did we attempt to determine

independently whether Brain Fingerprinting is a valid technique.

We performed our work from January 2001 to August 2001 in accordance

with generally accepted government auditing standards.

Several federal agencies are involved in researching, developing, or using

techniques to detect deception and have interacted, to varying degrees,

with the developer since the early 1990s. CIA’s Directorate of Science and

Technology researches, develops, and applies enabling technologies in

support of the agency’s mission to collect, process, and analyze foreign

intelligence and counterintelligence information. From 1991 to 1993, the

Directorate’s forerunner, the Office of Research and Development, funded

the developer about $1 million for research involving experimental studies

 4

Harrington v. Iowa, No. PCCV 073247 (Dist. Ct. Iowa, Mar. 5, 2001).

Background
Page 5 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

designed to evaluate and improve techniques for detecting concealed

information using electrical brain wave measurements.5

Components within DOD, including the DOD Polygraph Institute and

Defense Security Service,6

 are involved with detection of deception

research, such as brain wave research, and are knowledgeable about Brain

Fingerprinting. The Polygraph Institute’s research mission is to evaluate

the validity of psychophysiological detection of deception techniques used

by DOD and other agencies, investigate countermeasures (i.e., deliberate

techniques used by deceptive subjects to avoid detection during a

polygraph examination) and anticountermeasures, and conduct

developmental research on psychophysiological detection of deception

techniques, instrumentation and analytic methods. According to the

Polygraph Institute, the agency’s most recent contact with the developer

occurred in 1999, when he met with the Chief of Research to discuss the

Polygraph Institute’s grants program.

Within FBI, the Laboratory Division researches, develops, and deploys

new forensic techniques and technologies. The Division evaluated the

Brain Fingerprinting technique in 1993 and 1999. In addition, two agents

within FBI’s Behavioral Science Unit7

 and the Laboratory Division had

collaborated with the developer on related research in 1992 and 1993.

The Secret Service’s Forensic Services Division, which manages its

polygraph programs nationwide, conducts examinations involving

criminal, national security, and employee screening matters. In 1998, a

representative of the developer had contacted the division in an effort to

provide the agency with information on the technique. The division

 5

In the mid- to late 1980s, CIA also contributed funding to a collaborative effort on brain

wave detection of deception research conducted by the developer and another scientist.

6

As a federally funded agency, the Polygraph Institute’s purpose is to qualify DOD and nonDOD federal personnel for careers as forensic psychophysiologists; provide continuous

research in forensic psychophysiology and credibility assessment methods; manage the

continuing education certification program for all federal agencies; and manage the Quality

Assurance Program that maintains quality standards and provides technical assistance to

the federal polygraph programs. In 1997, operational responsibilities for the Polygraph

Institute were placed within the Defense Security Service.

7

Located in FBI’s Training Division, the Behavioral Science Unit conducts forensic research

with a focus on new and innovative investigative approaches related to offender

psychology and behavior.
Page 6 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

subsequently reviewed the information and consulted with a CIA official

because of the official’s knowledge of and experience with the technique.

According to its developer, Brain Fingerprinting is designed to determine

whether an individual recognizes specific information related to an event

or activity by measuring electrical brain wave responses to words,

phrases, or pictures presented on a computer screen. The technique can

be applied only in situations when investigators have a sufficient amount

of specific information about an event or activity that would be known

only to the perpetrator and investigator. In this regard, Brain

Fingerprinting is considered a type of Guilty Knowledge Test.8

 Only the

guilty party is expected to react strongly to the relevant details of the

event or activity. Its developer has indicated that Brain Fingerprinting,

therefore, is not designed for screening functions, which involves

questioning individuals about events unknown to the investigator. Rather,

the developer has indicated that an investigator would be able to use this

information as evidence for or against a suspect. For example, he has

indicated that the technique could be used to determine whether a suspect

has knowledge of details connecting him or her to a crime.

Brain Fingerprinting uses an EEG to record distinct patterns of brain

activity. These patterns, called event-related potentials, are measures of

the brain’s electrical activity or “potentials” as they correspond to stimuli

or “events” in the environment. By averaging the distinct patterns of

electrical activity, a singular waveform is created that is generally

dissected into various components associated with cognitive functions.

The event-related potential components relevant to Brain Fingerprinting

are the P300 and the Memory and Encoding Related Multifaceted

 8

There are two behavioral paradigms that have been used in detecting deception: the Guilty

Knowledge Test and Control Question Test. Generally, a Guilty Knowledge Test involves

presenting a subject with a series of questions, some of which are relevant to the crime in

question and some of which are irrelevant to the crime. It is expected that a subject who

possesses “guilty knowledge” will respond differently to the crime-relevant questions than

to the irrelevant questions, while an innocent individual will respond no differently to the

crime-relevant than to the irrelevant questions. A Control Question Test, in contrast,

involves relevant questions directly related to the crime, irrelevant questions unrelated to

the crime, and control questions. The control question is designed to inquire about general

criminal behavior that a large portion of the population may have done and that has

nothing to do with the crime under investigation, such as “When you were a teenager, did

you ever steal anything?” It is expected that the control question will elicit an emotional

response in the innocent subject that exceeds the response to the relevant question, while

the relevant question will elicit the larger emotional response in the guilty subject.

How Brain

Fingerprinting Is

Intended to Work
Page 7 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

Electroencephalographic Response (MERMER). The P300 component has

been recognized by the scientific community as an electrically positive

charge that peaks between about 300 and 500 milliseconds in response to

rare, meaningful, or noteworthy stimuli. The MERMER, patented by the

developer, includes the P300 and subsequent electrical changes occurring

at about 800 to 1200 milliseconds after a stimulus has been presented to a

subject. According to the developer, MERMER has not undergone

independent peer review testing and is not well accepted in the scientific

community.

The developer has indicated that use of the Brain Fingerprinting technique

should involve the following procedure. An examiner or investigator with

expertise in the Brain Fingerprinting technique reviews and identifies

evidence related to an event or activity through various means, such as

personal interviews, police records, court testimony, crime scene photos

or a crime scene. From this information, the examiner or investigator

chooses the stimuli to present to the subject in the form of words, phrases,

or pictures, which are flashed on a video monitor under computer control.

The three types of stimuli are categorized as “targets,” “irrelevants,” and

“probes.” Targets are made relevant and noteworthy to the subject by

giving him or her a list of the targets before the test is administered. Since

they are noteworthy, they should elicit a P300 response. A second set of

stimuli are irrelevant to the event or activity, although they could be

plausible substitutes for actual details of the event or activity. These

stimuli should not elicit a P300 response. Interspersed with the irrelevant

stimuli are less frequent stimuli called probes. Probes are unique details of

the event or activity that are supposed to be known only to the examiner

or investigator and the subject. For a subject with knowledge of the event

or activity, probes should elicit a P300. For a subject lacking that

knowledge, probes should be indistinguishable from the irrelevants and

should not elicit a P300.

The responses to the three types of stimuli are compared using a statistical

method,9

 which according to the developer, can yield an “information

 9

This refers to bootstrapping, which is a nonparametric statistical technique for inferring

the distribution of a statistic from a sample and for determining how reliable that statistic

is as a measure for the population. As a type of resampling, bootstrapping randomly

generates an entire distribution of values using data from just one sample and allows one to

make inferences with an associated degree of confidence about a population parameter,

such as a mean, median, or total. Bootstrapping provides a means to estimate standard

errors of sample statistics without requiring assumptions about the distribution of the

underlying population.
Page 8 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

present” (i.e., the subject recognized the information) or “information

absent” (i.e., the subject did not recognize the information) result.

According to the developer, Brain Fingerprinting, using P300 analysis, can

yield results with a statistical confidence level in excess of 95 percent. He

has further stated that MERMER provides the same results as the P300,

but with a higher confidence level—99 percent or more—because it

records more data points. In addition, he has stated that his research trials

have resulted in a 100 percent accuracy rate for determinations of

information present or information absent.

In April 2000, the developer administered the Brain Fingerprinting test to

an individual convicted of murder in Iowa in 1978. In November 2000, this

individual subsequently petitioned an Iowa district court for

postconviction relief, arguing, among other things, that the Brain

Fingerprinting test results demonstrated his innocence. The court

addressed the Brain Fingerprinting evidence in a written ruling dismissing

the application for postconviction relief. The court ruled that the Brain

Fingerprinting evidence was unlikely to have changed the result of the

defendant’s trial. In this regard, the court observed that, although the P300

effect was well established, neither the MERMER nor the developer’s

mathematical model was well accepted in the scientific community or had

been subject to independent testing or peer review. The court also

remarked that the selection of probe stimuli was subjective and did not, in

this case, meet the developer’s own selection criteria because various

stimuli were not sufficiently significant or had been disclosed to the

defendant at trial.10

CIA, DOD, FBI, and Secret Service do not foresee using the Brain

Fingerprinting technique for their operations because of its limited

application. Both CIA and DOD officials, for example, expressed the need

for a tool for screening purposes, for which Brain Fingerprinting is not

designed. The Secret Service indicated that the agency has had a high

success rate with the polygraph as an interrogative and screening tool and

therefore saw limited use for the technique. Within FBI, the Laboratory

Division concluded that Brain Fingerprinting had limited applicability to

 10See Harrington v. Iowa, No. PCCV 073247 (Dist. Ct. Iowa, Mar. 5, 2001). The Harrington

court applied Iowa law to the facts of the case. We did not identify any federal court

opinion addressing P300 or MERMER technology.

Federal Agency Views

on Brain

Fingerprinting’s

Potential Application
Page 9 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

FBI’s investigative and screening functions and identified other research

and operational concerns that would preclude its usefulness.

From their experiences with the developer’s research between 1991 and

1993, CIA officials concluded that Brain Fingerprinting had limited

applicability to CIA’s operations. Accordingly, CIA decided that it was not

worth investing more funds to continue the developer’s research.

Specifically, CIA officials told us that the technique had limited application

to CIA activities because it did not have a screening capability, which is of

primary interest to CIA. These officials explained that to administer Brain

Fingerprinting, an investigator must know enough details of a particular

event to test an individual for knowledge of that event. For example, these

officials said that using Brain Fingerprinting to determine an agent’s

involvement in espionage would be difficult because the investigator

would be hard-pressed to identify unique stimuli; in counterintelligence,

specific details are not always available because spying is not always

known to have taken place. Moreover, CIA officials indicated that a

perceived operational limitation of the technique was that it required a

trained scientist to administer the Brain Fingerprinting test.

In addition, CIA officials indicated that as an ordinary step in evaluating

advanced research and development work, the agency had assembled a

panel of independent researchers in 1993 to assess the analytic methods

employed by the developer to ensure that they were scientifically sound

and defensible. CIA officials stated that while the panel indicated that the

technique appeared interesting, it was not able to assess the validity of the

work because the developer would not provide the algorithmic

information that was critical to completing such an assessment. According

to CIA officials, the developer considered the information proprietary.

Those officials indicated that no additional research funding was provided

following the panel evaluation.

Overall, DOD officials indicated that Brain Fingerprinting has limited

applicability to DOD’s operations. According to these officials, DOD

priorities are for screening prospective and current employees. However,

as acknowledged by its developer, Brain Fingerprinting is not designed as

a screening tool. DOD’s Polygraph Institute indicated that, with a limited

budget of $400,000 a year, it focuses its resources on conducting research

related to employment screening techniques, which is a major area of

interest for DOD. The Polygraph Institute also indicated that it is currently

funding other brain wave detection of deception research, which the

agency believes may lead to applications that could meet DOD’s needs.

CIA Views

DOD Views
Page 10 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

Regarding Brain Fingerprinting’s applicability to criminal investigations,

DOD officials acknowledged that DOD conducts a limited number of

specific issue examinations where the technique could be applied. DOD

officials indicated that most DOD criminal investigations do not lend

themselves to a Guilty Knowledge Test-based technique, such as Brain

Fingerprinting, because these kinds of investigations typically lack the

specific information that is needed for administering such a test and

because knowledge of the discrete elements of an event or activity may

not be limited to only the investigator and the perpetrator.

According to FBI officials, in 1993, the Laboratory Division’s Polygraph

Unit and CIA collaborated in an effort to evaluate and validate the Brain

Fingerprinting test. At that time, the Polygraph Unit concluded the

following.

• The developer had not presented sufficient information to demonstrate

validity or the underlying scientific basis of his assertions. For example,

the FBI asked the developer to provide details of all tests conducted,

particularly in a law enforcement setting, which would support validation.

FBI officials indicated that the developer maintained that his technique

was proprietary.

• The technique had limited applicability and usefulness to FBI investigative

and personnel security matters.

• The research expenses, equipment, and training costs exceeded any

perceived benefit.

• According to the developer, only individuals with advanced academic

degrees—trained in psychophysiology or a related science—could be used

to operate the system. The Polygraph Unit indicated that this eliminated a

large segment of the FBI population as potential operators.

FBI officials indicated that, in 1999, the Laboratory Division assembled a

panel of reviewers and conducted another evaluation of the technique,

based on a demonstration provided by the developer. The panel concluded

that since substantially no additional research had been done since 1993,

the conclusions that had been reached at that time had not changed.

In addition, the panel raised concerns about the technique’s limited utility

for employment screening applications and security matters. Furthermore,

the panel indicated that the developer had not done research on the

effects of external variables on brain activity, such as drugs, alcohol, or

hallucinogenic drugs. FBI officials who participated in the panel explained

that Brain Fingerprinting relies on retained memory, which they do not

FBI Views
Page 11 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

believe is always a reliable record of events. Thus, they were concerned

about possible changes or deletions from memory. These officials further

explained that, as part of evaluating the validity of Brain Fingerprinting as

an investigative technique, they must understand the effects of alcohol and

other drug use on the brain in its processes for storing and retrieving

information.

Separately, two FBI agents who had conducted research with the

developer expressed a different view. These individuals, in the Behavioral

Science Unit and Laboratory Division, believe that Brain Fingerprinting

has potential for use in FBI criminal investigations. Both agents, however,

recognize that FBI’s current investigative techniques and practices do not

require documenting the type of incidental crime scene information that

could be used in constructing the probe stimuli. Specifically, they

indicated that FBI agents and investigators do not record this kind of

detailed information on the form that FBI uses to document crime scene

information during an investigation. One of these agents pointed out that

these investigators and agents would need to be trained in collecting

specific and detailed crime scene information—such as the color of a

sofa—that may not normally appear relevant at a crime scene or that had

nothing to do with the crime committed, but could prove important as a

probe stimulus. This agent also indicated that FBI would need to establish

a means for protecting the crime scene information from public disclosure

so as not to jeopardize the integrity of the test. The agent pointed out,

however, that FBI’s use of this technique would require a shift in FBI’s

investigative and training methods, which is essentially a policy issue that

would have to be addressed by FBI management.

One of these agents believes that while Brain Fingerprinting is ready for

forensic application, it could benefit from continued research and

development, such as refining the probe stimuli and determining whether

certain types of probes are more likely to be remembered than others.11 In

addition, this agent indicated that because drugs and alcohol are

frequently used in committing crimes, research is needed to determine

what effect they may have on memory. The second agent believes that

Brain Fingerprinting is not ready for operational use and needs more

research to be able to establish its viability in criminal cases.

 11Toward the latter part of our review, this agent retired from the FBI and is currently a

business associate of the developer.
Page 12 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

An official representing the Forensic Services Division indicated that, in

1998, the Secret Service reviewed information provided by the developer

and consulted with a CIA official because of the official’s knowledge of

and experience with the Brain Fingerprinting technique. The Service

subsequently concluded that the technique had limited application to

Secret Service activities. The official further indicated that the agency has

had a high success rate with the polygraph as an interrogative and

screening tool.

In letters dated October 5, 2001, we requested comments on a draft of this

report from CIA, DOD, Secret Service, FBI, and the developer of the Brain

Fingerprinting technique, Dr. Farwell. In addition, we requested that the

three scientists we interviewed—Drs. Donchin, Iacono, and

Rosenfeld— review our summaries of their views for technical accuracy

and clarification.

Overall, CIA, DOD, Secret Service, and FBI agreed with the report and our

presentation of their views. On October 17, 2001, we met with Dr. Farwell

to discuss the draft report. At that time, he indicated that he had no

comments or technical corrections on the report. In addition, Drs.

Donchin, Iacono, and Rosenfeld separately provided technical comments

and clarifications, which we have included where appropriate.

CIA and DOD provided oral comments on a draft of this report.

Specifically, CIA’s Directorate of Science and Technology indicated

agreement with the contents of the report and had no other comments.

DOD’s Office of the Assistant Secretary of Defense for Command, Control,

Communications and Intelligence indicated DOD’s concurrence with the

report and restated its position that the Brain Fingerprinting technique had

limited application to DOD’s operations.

The Forensic Services Division of the Secret Service provided written

comments that essentially reiterated its position that Brain Fingerprinting

had limited applicability to the Secret Service. Those comments are

included in appendix II.

FBI’s Office of Public and Congressional Affairs provided the Bureau’s

oral comments, which we have incorporated in this report. The Office also

submitted the Bureau’s written comments, which we have included in

appendix III. Specifically, FBI indicated that the report fairly reflected the

FBI’s position that the technique has limited applicability and usefulness

to FBI investigative and personnel security matters. Further, FBI indicated

that—on the basis of its own research in forensic science and the scientific

Secret Service Views

Agency Comments

and Our Evaluation
Page 13 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

views expressed in this report—it strongly disagreed with one of its

agents’ assessments of the technique. As discussed earlier in the report,

this agent had indicated that while the technique could benefit from

continued research and development, it was nevertheless ready for

forensic application.

As arranged with your office, unless you publicly announce its contents

earlier, we plan no further distribution of this report until 30 days after its

date. At that time, we will send copies to appropriate congressional

committees; the Attorney General; Secretary of DOD; Directors of CIA,

FBI, Secret Service, and Office of Management and Budget; and other

interested parties. Copies of this report will also be available to others on

request.

If you or your staff have any questions, please call Linda Watson or me at

(202) 512-8777. Key contributors to this report were Christine Davis, Sam

Hinojosa, Brenda Rabinowitz, Keith Rhodes, and Anne Rhodes-Kline.

Sincerely yours,

Paul L. Jones

Director, Justice Issues
Appendix I: Scientists’ Views on the Brain

Fingerprinting Technique

Page 14 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

The purpose of this appendix is to provide additional information on the

Brain Fingerprinting technique. Specifically, we interviewed three

scientists who were familiar with the technique: Emanuel Donchin, Ph.D.;

William Iacono, Ph.D.; and J. Peter Rosenfeld, Ph.D. Each scientist shared

his view of the technique, raising questions and providing insights related

to some of the methods that underlie Brain Fingerprinting. These

scientists expressed a need for more research to demonstrate Brain

Fingerprinting’s application as an investigative tool. However, these views

are not representative of scientists’ views in general, nor do they represent

a complete or systematic review of the technique. The following sections

provide the views of the three scientists.

Dr. Donchin1 co-authored a journal article with Dr. Farwell in 1991 in

which use of the P300 in a Guilty Knowledge Test was first described.2

 Dr.

Donchin believes that the procedure described in the article (labeled more

recently as “Brain Fingerprinting” by Dr. Farwell) utilizes the scientifically

well-established observation that rare events (i.e., stimuli) presented

within the so-called “oddball paradigm”

3

 will elicit a P300 component of

the event-related potential. He indicated that a large body of peer-reviewed

scientific literature, developed since 1965, supports this observation.

However, Dr. Donchin believes that the specific application of the oddball

 1

Dr. Donchin, Professor Emeritus of psychology at the University of Illinois at UrbanaChampaign and current professor and chair of psychology at the University of South

Florida, has done extensive research in event-related potentials, the P300, and memory

processes. He also served as the developer’s academic advisor during his doctorate studies

at the University of Illinois, and, in this capacity, conducted detection of deception

research with him that was funded, in part, by the CIA in the late 1980s.

2

See L.A. Farwell, and E. Donchin, “The Truth Will Out: Interrogative Polygraphy (‘Lie

Detection’) With Event-Related Brain Potentials,” Psychophysiology 28 (5): 531-47.

3

The Brain Fingerprinting technique is a variant of the “oddball paradigm,” which has been

widely used by cognitive neuroscientists to evoke a P300 wave in an event-related potential

recorded from the scalp. As indicated earlier, the P300 is an electrically positive charge that

is elicited in response to rare, meaningful stimuli, and event-related potentials are

measures of the brain’s electrical activity as they correspond to those stimuli. The classic

way to evoke the P300 is to present stimuli to a subject using the oddball paradigm. In this

paradigm, two categories of stimuli are presented to a subject, but one of these categories

appears more infrequently than the other. Research has shown that each time a subject is

presented with the less frequent stimuli, the P300 is elicited. For example, if a subject is

viewing a random series of names—one every 3 seconds—and occasionally, one of these

names is the subject’s, a P300 wave is evoked in response to this rarely presented, yet

meaningful stimulus. The amplitude of the P300 is inversely proportional to the probability

of the “oddball” stimuli. As a variant of the oddball paradigm, the Brain Fingerprinting

technique uses three categories of stimuli.

Appendix I: Scientists’ Views on the Brain

Fingerprinting Technique

Views of Emanuel Donchin
Appendix I: Scientists’ Views on the Brain

Fingerprinting Technique

Page 15 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

paradigm for interrogations requires much further research. For example,

he believes that the effectiveness of the Brain Fingerprinting test and its

validity depends to a large extent on the events (i.e., stimuli) of which the

oddball sequence is constructed. Specifically, he believes that the

interpretation of the Brain Fingerprinting test results depends on the

selection of the probe stimuli, which is left to the examiner’s subjective

judgment and skill in utilizing the available case information. Dr. Donchin

indicated that a consequence of using a subjective method for choosing

probe stimuli is the possibility of producing “false positives” (i.e., an

innocent subject that would test positive when presented with a probe

stimulus) or “false negatives” (i.e., the items chosen as probes because of

their presumed association with the crime may not have been noticed by

the subject during the commission of the crime). As an example, he

provided a hypothetical case in which a person’s involvement in a crime

was inferred from the fact that the person produced a P300 response to

pictures of people who were present at the crime scene. He said that the

possibility exists that these individuals resemble close relatives of the

suspect, resulting in an elicitation of a P300 response that could be

misinterpreted as an indication of guilt. Dr. Donchin believes that a more

systematic and objective method for identifying and choosing the events

for use in the oddball sequence is needed before the technique could be

trusted to yield unambiguous determinations.

Dr. Donchin also indicated that he believes it is important to realize that

memory is an active, creative process and not a passive repository of

stored images. He believes that while the P300 is a well-established and

documented phenomenon for determining whether an event (i.e.,

stimulus) has been classified as an item of a rare category, it is not clear

that every item that is classified is one to which the person has been

exposed to in the past. He referred to the phenomenon of “false memory”

and said he believes that research has amply demonstrated that individuals

can report a vivid memory that may be quite false. For example, a subject

presented with a list of sleep-related items—such as “bed,” “sheet,”

“dream,” and “snore”—will be certain that he or she had also been

presented with the word “sleep,” even though it had not been included

among the items presented. Dr. Donchin pointed out that the “falsely

recognized item,” however, will elicit a sizable P300 response.

In addition, Dr. Donchin believes that more research is needed to

understand the effects of age; substances, such as alcohol and drugs; and

psychological disorders on memory and the P300.
Appendix I: Scientists’ Views on the Brain

Fingerprinting Technique

Page 16 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

Dr. Iacono4 believes that Brain Fingerprinting is based on a documented

and well-established phenomenon—the P300 response—as an indicator of

a novel or unexpected stimulus event. However, he indicated that far

fewer studies have examined the P300’s potential to identify memories

that are stored in an individual’s brain. Hence, as an indicator of memory,

the technique is less established.

Dr. Iacono believes that the Brain Fingerprinting technique is in its early

stages of development and could benefit from more field research and

testing before being applied to actual criminal investigations for the

following reasons. For one, he believes that research has shown that

investigating a murder in the field is entirely different from investigating a

murder in a lab. Further, he believes that the technique could benefit from

additional field research and testing to develop the probe stimuli. He

believes that selecting the appropriate probe stimuli can be a subjective

process, which he does not perceive as a criticism of the technique.

However, he suggests that additional field research and testing be done on

real-life applications to help identify which probes are better suited for the

test. He also suggests a need for more field research to determine the

effects that drugs and alcohol intoxication—at the time the crime is

committed—may have on subsequent measurement of the P300. In

addition, he believes that it is possible that certain drugs taken at the time

of the Brain Fingerprinting test could affect memory and thus, the validity

of the test. Dr. Iacono does not believe adequate research has been done in

this area to understand the effects of these chemicals on the Brain

Fingerprinting test. He added that although Brain Fingerprinting is

unproven in the field, he is confident that it will prove itself for many

applications, such as the investigation of carefully planned premeditated

crimes.

 4

Dr. Iacono, a professor of psychology and neuroscience at the University of Minnesota,

has done extensive research in the area of deception detection and memories related to

deception.

Views of William Iacono
Appendix I: Scientists’ Views on the Brain

Fingerprinting Technique

Page 17 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

On a separate issue, Dr. Iacono indicated that he employed the same

statistical method5

 and decision rules the developer used in the 1991

article by Farwell and Donchin, which Dr. Iacono noted have been peer

reviewed and are well established in the scientific community. Dr. Iacono

stated that he assumes that the developer is still using those decision rules

in interpreting the results of the Brain Fingerprinting test. However, Dr.

Iacono indicated that he has not replicated the decision rules that the

developer used after the 1991 article.

Dr. Rosenfeld6

 believes that a considerable amount of research and field

testing is necessary to establish the validity of event-related potential

measures in detecting deception using a Guilty Knowledge Test. He

indicated that only one field test has applied the Guilty Knowledge Test in

a law enforcement setting, which resulted in an accuracy rate of about 44

percent.7

 In addition, Dr. Rosenfeld does not believe that the developer

had done the extensive validation of the test items for field use that has

 5

Dr. Iacono refers to the previously mentioned 1991 journal article by Farwell and Donchin

that involved the feasibility of using event-related potentials based on a Guilty Knowledge

Test. That research employed a bootstrapping method. As indicated earlier, bootstrapping

is a nonparametric statistical technique for inferring the distribution of a statistic from a

sample and for determining how reliable that statistic is as a measure for the population.

As a type of resampling, bootstrapping randomly generates an entire distribution of values

using data from just one sample and allows one to make inferences with an associated

degree of confidence about a population parameter, such as a mean, median, or total.

Bootstrapping provides a means to estimate standard errors of sample statistics without

requiring assumptions about the distribution of the underlying population.

6

Dr. Rosenfeld, a professor of psychology and member of the Institute for Neuroscience at

Northwestern University, has done extensive research in electroencephalograph and eventrelated potential signs of psychological function, with a particular focus on the P300, false

memory, and brain activity in deception detection.

7

Dr. Rosenfeld refers to a 1993 study by Y. Miyake, M. Mizutani, and T. Yamahura, “EventRelated Potentials as an Indicator of Detecting Information in Field Polygraph

Examinations,” Polygraph 22 (2): 131-49.

Views of J. Peter Rosenfeld
Appendix I: Scientists’ Views on the Brain

Fingerprinting Technique

Page 18 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

been recommended by the Guilty Knowledge Test’s main proponent.8

Specifically, he believes that in administering the Brain Fingerprinting test

to the defendant in the Harrington case, the developer used “art rather

than science” in developing the stimuli that were administered to the

defendant. He questioned how one would know whether the items

selected for a guilty knowledge scenario would be sure to work on any

guilty party. In addition, Dr. Rosenfeld said he believes there has been only

one peer-reviewed journal article—the 1991 Farwell and Donchin article

previously mentioned—that includes the developer’s methods.

Dr. Rosenfeld also indicated he does not believe that memory

automatically stores all of life’s experiences forever. He indicated that

current research has shown that memory is affected by various chemicals

and conditions, such as alcohol and drugs, brain damage, mental illness,

and extreme anxiety, during crime situations. He pointed to the example

of extreme anxiety, suggesting that if someone just killed his wife, anxiety

might prevent him from noticing what color shoes she was wearing. He

does not believe the developer has done research on these issues.

In terms of the Brain Fingerprinting’s test results, Dr. Rosenfeld

questioned the developer’s claim of a 100-percent accuracy rate. For

example, he raised concerns regarding whether the developer omitted

inconclusive results from the totals, which would affect the overall

accuracy rate. Further, Dr. Rosenfeld believes the accuracy rate would be

lower in the field, where variables cannot be so well controlled. Moreover,

he believes that the developer’s criterion for guilt is that 90 percent of the

bootstrapping iterations of his analysis be positive. Dr. Rosenfeld stated

that, in experimental psychology journals, the 95-percent criterion is

generally used and that too lenient a criterion will ordinarily make more

 8

The Guilty Knowledge Test was introduced by David Lykken, Ph.D., a psychologist and

former professor of psychiatry at the University of Minnesota, and polygraph critic. In his

book, A Tremor in the Blood, Dr. Lykken has recommended that a Guilty Knowledge Test

include probes that satisfy certain conditions. Specifically, he recommended that for each

probe, an innocent subject should have no more than a 20-percent chance of testing

positive and a guilty subject should have at least an 80-percent chance of testing positive.

Each probe should have five alternatives that are equally plausible to an innocent subject,

but, to the guilty subject, are easily distinguishable from the probe and from each other, so

that the guilty subject is not confused about which alternative he or she has seen before. In

addition, the fact that a guilty subject recognizes a probe “must seem important to the

guilty subject,” a condition that should always be realized in a criminal investigation

context but may not be in some laboratory experiments.
Appendix I: Scientists’ Views on the Brain

Fingerprinting Technique

Page 19 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

guilty decisions but will also produce more false positives (i.e., innocents

judged guilty).

Furthermore, Dr. Rosenfeld believes that the P300 is a good index of

recognition, but an indirect index of deception. It assumes that if the

subject states that he or she does not recognize the murder weapon, yet

elicits a P300 when he or she sees it, then the subject is lying. He adds that

such a conclusion leads to a reasonable, but not infallible inference that

the subject is lying. However, a P300 response only indicates that there is

something special and recognizable to him or her about that weapon—

maybe because the subject committed the murder, but maybe because he

or she read about the weapon in the news or because a brother has such a

weapon. Dr. Rosenfeld indicated that there are no direct deception indices

known at present but noted that researchers are working on one.
Appendix II: Comments From the U.S. Secret Service

Page 20 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

Appendix II: Comments From the U.S. Secret

Service
Appendix II: Comments From the U.S. Secret Service

Page 21 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"
Appendix III: Comments From the Federal

Bureau of Investigation

Page 22 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"

Appendix III: Comments From the Federal

Bureau of Investigation
Appendix III: Comments From the Federal

Bureau of Investigation

Page 23 GAO-02-22 Federal Agency Views on "Brain Fingerprinting"
Appendix III: Comments From the Federal

Bureau of Investigation

Page 24 GAO-02-22 Federal Agency Views on "Brain Fingerprinting" (440010)
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