
Telling A
Lie? Brain Scans May Rat You Out!
Both labs use brain-scanning technology
called functional magnetic resonance imaging, or fMRI. It's a standard
tool for studying the brain, but research into using it to detect lies
is still in early stages. Nobody really knows yet whether it will prove
more accurate than polygraphs, which measure things like blood pressure
and breathing rate to look for emotional signals of lying.
But advocates for fMRI say it has the
potential to be more accurate, because it zeros in on the source of
lying, the brain, rather than using indirect measures. So it may
someday provide lawyers with something polygraphs can't: legal evidence
of truth-telling that's widely admissible in court. (Courts generally
regard polygraph results as unreliable, and either prohibit such
evidence or allow it only if both sides in a case agree to let it in.)
Laken said he's aiming to offer the fMRI
service for use in situations like libel, slander and fraud where it's
one person's word against another, and perhaps in employee screening by
government agencies. Attorneys suggest it would be more useful in civil
than most criminal cases, he said.
Of course, there's no telling where the
general approach might lead. A law review article has discussed the
legality of using fMRI to interrogate foreigners in U.S. custody. Maybe
police will use it as an interrogation tool, too, or perhaps major
companies will find it a cheaper than litigation or arbitration when an
employee is accused of stealing something important, other observers
say.
For his part, Shapiro says he'd switch to
fMRI from polygraph for screening certain clients because he figures it
would be more reliable and maybe more credible to law enforcement
agencies.
In any case, the idea of using fMRI to detect
lies has started a buzz among scientists, legal experts and ethicists.
Many worry about rushing too quickly from the lab to real-world use.
Some caution that it may not work as well in the real world as the
early lab results suggest.
And others worry that it might.
Unlike perusing your mail or tapping your
phone, this is "looking inside your brain," Hank Greely, a law
professor who directs the Stanford Center for Law and the Biosciences,
told me a few days before my scan.
It "does seem to me to be a significant
change in our ability ... to invade what has been the last untouchable
sanctuary, the contents of your own mind," Greely said. "It should make
us stop and think to what extent we should allow this to be done."
But Dr. Mark George, the genial neurologist
and psychiatrist who let me lie in his scanner and be grilled by his
computer, said he doesn't see a privacy problem with the technology.
That's because it's impossible to test people
without their consent, he said. Subjects have to cooperate so fully -
holding the head still, and reading and responding to the questions,
for example - that they have to agree to the scan.
"It really doesn't read your mind if you
don't want your mind to be read," he said. "If I were wrongly accused
and this were available, I'd want my defense lawyer to help me get
this."
So maybe the technology is better termed a
"truth confirmer" than lie detector, he said.
Whatever you call it, the technology has
produced some eyebrow-raising results. George and his colleagues
recently reported that using fMRI data, a computer was able to spot
lies in 28 out of 31 volunteers.
I joined an extension of that study. That's
why I found myself lying on a narrow table in George's lab while he and
his assistants pulled a barrel-shaped framework over my head like a
rigid hood. As it brushed the tip of my nose and blotted out the light
from the room, I looked straight ahead to see a computer screen, which
would be my interrogator.
Then the table eased into the tunnel of the
fMRI scanner, a machine the size of a small storage shed. Only my legs
stuck out.
As I focused on the questions popping up on
the computer screen, the scanner roared like a tractor trying to uproot
a tree stump.
It was bombarding me with radio waves and a
powerful magnetic field to create detailed images of my brain and
detect tiny changes in blood flow in certain areas. Those changes would
indicate those areas were working a bit harder than usual, and
according to research by George and others, that would in turn indicate
I was lying.
Some questions that popped up on that screen
were easy: Am I awake, is it 2004, do I like movies. Others were a
little more challenging: Have I ever cheated on taxes, or gossiped, or
deceived a loved one. As instructed, I answered them all truthfully,
pushing the "Yes" button with my thumb or the "No" button with my index
finger.
Then, there it was: "Did you remove a watch
from the drawer?"
Just a half-hour or so before, in an adjacent
room, I'd been told to remove either a watch or a ring from a drawer
and slip it into a locker with my briefcase. This was the mock crime
that volunteers lied about in George's study. So I took the watch. As I
lay in the scanner I remembered seizing its gold metal band and
nestling it into the locker.
So, the computer was asking, did I take the
watch?
No, I replied with a jab of my finger. I
didn't steal nuthin.'
I lied again and again. Other questions about
the watch popped up seemingly at random during the interrogation. Is
the watch in my locker? Is it in the drawer? Did I steal it from the
drawer?
The same questions came up about the ring,
and I told the truth about those.
It would be a different computer's job to
figure out which I was lying about, the watch or the ring. It would
compare the way my brain acted when I responded to those questions
versus what my brain did when I responded truthfully to the other
questions. Whichever looked more different from the "truthful" brain
activity would be considered the signature of deceit.
Finally, after answering 160 questions over
the course of 16 minutes - actually, it was 80 questions two times
apiece - I was done. The machine returned me to the bright light of the
scanning room.
The computer's verdict? That would take a few
days to produce, since it required a lot of data analysis. I didn't
mind waiting. It's not like the result would help get me fired, or lose
a lawsuit, or send me to jail.
Nobody in George's studies faced consequences
like that, which is one reason the lab results may not apply to
real-world situations. George has already begun another study in which
volunteers face "a little more jeopardy" from the mock crime. He
declined to describe it because he didn't want prospective volunteers
to hear about it ahead of time. That work is funded by the Department
of Defense Polygraph Institute.
Other questions remain. How would this work
on people with brain diseases? Or people taking medications? How would
this work on people outside the 18-to-50 age range included in George's
recent work?
How about experienced liars? George hopes
eventually to study volunteers from prisons.
And then there's the matter of the three
people who got away with lying in his recent study. For some reason,
the computer failed to identify the object they'd stolen. George says
he doesn't know what went wrong.
But in a real-world situation, he said, the
person being questioned would go through an exercise like the
ring-or-watch task as well as being quizzed about the topic at hand.
That way, if the computer failed in the experimental task, it would be
obvious that it couldn't judge the person's truthfulness.
Because of that, George said, he's
comfortable with entrepreneur Laken's plans to introduce the scanning
service to lawyers, though just on a limited basis, by the middle of
this year. Lab studies are obviously necessary, he said, but "at a
certain point you really have to start applying and see how it works.
And I think we're getting close."
But Jennifer Vendemia, a University of South
Carolina researcher who studies deception and the brain, said she finds
Laken's timetable premature. So little research has been done on using
fMRI for this purpose that it's too soon to make any judgment about how
useful it could be, she said.
Without studies to see how well the technique
works in other labs - a standard procedure in the scientific world -
its reliability might be an issue, said Dr. Sean Spence of the
University of Sheffield in England, who also studies fMRI for detecting
deception.
Speaking more generally, ethical and legal
experts said they were wary of quickly using fMRI for spotting lies.
"What's really scary is if we start
implementing this before we know how accurate it really is," Greely
said. "People could be sent to jail, people could be sent to the death
penalty, people could lose their jobs."
Greely recently called for pre-marketing
approval of lie-detection devices in general, like the federal
government carries out for medications.
Judy Illes, director of Stanford's program in
neuroethics, also has concerns: Could people, including victims of
crimes, be coerced into taking an fMRI test? Could it distinguish
accurate memories from muddled ones? Could it detect a person who's
being misleading without actually lying?
Her worries multiply if fMRI evidence starts
showing up in the courtroom. For one thing, unlike the technical data
from a polygraph, it can be used to make brain images that look simple
and convincing, belying the complexity of the data behind them, she
said.
"You show a jury a picture with a nice red
spot, that can have a very strong impact in a very rapid way.... We
need to understand how juries are going to respond to that information.
Will they be open to complex explanations of what the images do and do
not mean?"
There's also a philosophical argument in case
fMRI works all too well. Greely notes that four Supreme Court justices
wrote in 1998 that if polygraphs were reliable enough to use as
evidence, they shouldn't be admitted because they would usurp the
jury's role of determining the truth. With only four votes, that
position doesn't stand as legal precedent, but it's "an interesting
straw in the wind" for how fMRI might be received someday, he said.
It didn't take any jury to find the truth in
my case.
"We nabbed ya," George said after sending me
the results of my scan. "It wasn't a close call."
I was ratted out by the three parts of my
brain the technique targets. They'd become more active when I lied
about taking the watch than when I truthfully denied taking the ring.
Those areas are involved in juggling the
demands of doing several things at once, in thinking about oneself, and
in stopping oneself from making a natural response - all things the
brain apparently does when it pulls back from blurting the truth and
works up a whopper instead, George said.
Of course, nobody is going to make me or
anybody else climb into an fMRI scanner every time they want a
statement verified. The procedure is too cumbersome to be used so
casually, George says.
But he figures that if a perfect lie detector
were developed, that practical consideration might not matter. The mere
knowledge that one is available, he said, might provoke people to clean
up their acts.
"My hope," George said, "would be that it
might make the world operate a little bit more openly and honestly."
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