Your Brain In The Name Of Security
Editorial Director, BiometriTech
August 19, 2002
doing some in-depth research on biometric technologies recently, I came
across a subject I hadn't encountered before: brain fingerprinting. At
least I don't recall coming across it before -- perhaps a scan of my
brain would prove otherwise. The technology isn't a new concept, nor
does it rely on biometric traits, although it can best be used in tandem
with biometrics -- surprisingly -- to protect the privacy of those being
Brain fingerprinting was invented more than 10 years ago, when the
CIA invested some money in a psychologist, Emanuel Donchin, and his
student, Lawrence Farwell. The theory was to find out what they could do
to expand on a standard EEG test, which uses super-sensitive electrodes
to measure fluctuations in electrical potential caused by patterns of
brain activity. Donchin specialized in a characteristic bump in the EEG
scan called the P300, which occurs approximately a third of a second
after the subject being tested recognizes something significant.
Farwell continued testing the viability of using P300 for criminal
cases, and ended up patenting the Farwell Brain Fingerprinting method.
The system basically works by flashing words or pictures relevant to a
crime on a computer screen, along with irrelevant words and pictures.
Electrical brain responses are measured through a patented headband
equipped with sensors. Farwell discovered that a memory and encoding
related multifaceted electroencephalographic response (MERMER) was
elicited when the brain processed noteworthy information it recognized.
Therefore, if details of a crime only a perpetrator would know about
were presented, a MERMER would be emitted by the brain of the
perpetrator -- but not by the brain of an innocent suspect.
In Farwell's Brain Fingerprinting, a computer analyzes brain
responses to detect the MERMER, and determines whether or not the
crime-relevant information is stored in the brain of the suspect. This
is also known as Computerized Knowledge Assessment. One of the strongest
arguments for this type of testing is that human judgment doesn't enter
the picture -- the results are scientific. Whereas other forms of
questioning, like interrogation, involve intimidation and verbal
"persuasion," no verbal communication is required with brain
fingerprinting. And whereas lie detector tests have been known to fail,
especially among skilled liars who have learned how to skew results by
clenching their teeth, etc., the impulses of the brain supposedly cannot
be manipulated for the purposes of this test.
Of course, there's a laundry list of reasons why this method is not
foolproof. The first that comes to mind is that the crime-relevant
questions and pictures are chosen by humans, and are therefore
subjective. What if an innocent subject is shown an image of the crime
scene -- a place he or she has been to before, but not necessarily at
the time of the crime? What if certain details of the crime match up
with someone's similar experiences, and therefore recognition is
Farwell contends that his method has proven 100-percent accurate in
tests conducted on FBI agents, as well as in tests for a U.S.
intelligence agency and the U.S. Navy. It aided Missouri prosecutors in
convicting a serial killer in 1998, 14 years after the rape and murder
of Julie Helton. After J.B. Grinder underwent brain fingerprinting, in
which he responded positively to certain details of the crime, he
confessed to Helton's murder and was sentenced to life in prison. He
subsequently confessed to other murders of young women. Farwell also
presented test results to a court in Iowa in an attempt to exonerate a
man that had been convicted of a murder 22 years earlier, and who had
claimed innocence. Farwell said the test results showed, with 99.99
percent accuracy, that Terry Harrington had not committed the crime. The
test results prompted the only witness to the crime to recant his
testimony against Harrington in a sworn testimony, admitting it was a
fabrication. Yet the judge in the trial rejected the new evidence in a
2001 ruling, claiming it was unlikely to change the result of a trial.
Harrington is appealing the ruling.
Farwell is a strong proponent of using brain fingerprinting to screen
airline passengers, and as an added security measure at various
screening checkpoints. The theory is that people could be screened
without revealing their names, through the use of biometrics. For
instance, at the same time the brain wave test was given, biometric data
like fingerprint or iris scan would be gathered to link the person being
tested to their physical profile. The biometric profile would only need
to be updated once every few years. The person being tested would then
put on a headset and watch video images on a standard computer monitor
for 10 minutes. The test would be used to present data and information
terrorists are familiar with.
Since the brain fingerprinting would be completely automated, it
would not be subject to human interpretation, and therefore would be
unbiased to race, creed, color, sex, religion, and other individual
characteristics. The computerized security risk factor profile generated
by the brain fingerprinting would be linked to a person's biometric
data, but not necessarily to the person's name.
The very idea of brain fingerprinting conjures up images of a Big
Brother-like world in which knowing too much could be dangerous, and the
wrong response to an image could get you convicted of a crime you may or
may not have committed. Then again, if the technology is used correctly
and unobtrusively, perhaps it could be beneficial for screening out
terrorists or other threatening characters.
The one major flaw I see in it, however, is the contention that it is
100 percent automated, and therefore scientifically sound. The very
nature of the questioning that fuels the MERMER is subjective. Just as
the very nature of the information collected from a crime scene is
fueled by human input. Of course, there are standards and procedures for
collecting such information, just as I'm sure there will be standards
for questioning and video presentation if brain fingerprinting is ever
widely implemented by law enforcement. I just hope those adopting this
technology proceed with caution, as there is obviously a huge potential
for abuse and error.
was originally published as Laura Guevin's Points of Presence column on TMCnet.