O ne spring evening in 2005, Andre
LeClerc, a slight 37-year-old of medium height, walked
into a sparsely furnished room on
the Medical University of South Carolina campus. He crossed to a set of
green cupboards and drawers and quickly found what he was looking for:
a man’s gold watch and
a woman’s
white-gold ring set with turquoise stones. After
hesitating just a moment, he pocketed the ring and
left the room.
LeClerc was an investment adviser at a local bank.
He wasn’t a thief by nature, he was only doing what he’d been
asked. He had stolen something, and now he was going to lie about it.
The magnetic resonance image scanner—“Big Maggie,” as
it’s known at the university’s Center for Advanced Imaging
Research—stands in the center of a large room. Minutes after his
theft, as LeClerc lay inside the machine, a series of questions flashed
on a screen above him. Some were neutral: Do you like to swim? Do you
have a cat? He clicked one button for yes, another for no. And some were
not: Did you take the watch from the drawer? (No, LeClerc clicked, truthfully.)
Did you take the ring from the drawer? (No, again—a lie this time.)
Is the watch with your possessions? (No.) Did you hide the ring? (No—another
lie.)
The questions seemed endless, and LeClerc had to
remind himself of the extra $50 he’d been promised if he could fool
Big Maggie. When at last he was finished, he approached main investigator
F. Andrew Kozel. “So,” LeClerc said, “what did I take?”
It was a question most participants asked one way
or another. And though Kozel never tipped his hand (he gave everyone the
$50) to avoid tainting post-study interviews with subjects, nine times
out of 10 the answer to the basic query—Could you tell when I was
lying?—was yes.
Most of us lie, every day. Starting in early childhood,
we compliment, flatter and deliberately deceive to avoid conflict or to
gain advantage. Our closest nonhuman relatives also lie, though less often.
Among the more highly developed primate species, the larger the neocortex—the
outer surface of the brain involved in conscious thought—the more
frequent the primate’s deception.
But some lies are more damaging than others, and
there are those—employers, police, courts, government agencies—who
would pay dearly for the ability to distinguish truth from falsehood.
Until recently, tools for detection have been crude. But now, as scientists
find ways to peer inside our heads, several new lie detectors may be on
the verge of commercial applications—and are raising pointed scientific,
legal and ethical issues.
Early lie detectors, such as the polygraph, measured
brain activity indirectly, through signs of arousal—an increased
heart rate and perspiration, for instance. Psychologist William Moulton
Marston developed a polygraph prototype around the time of the First World
War. From the start, critics noted that the polygraph could easily be
confounded by intellectual and emotional stresses. Nevertheless, it was
widely adopted.
A review of polygraph studies by the National Academy
of Sciences in 2003 found that the test was generally better than chance
under laboratory conditions. But the review panel also pointed out that
most studies failed to consider possible countermeasures and could not
be generalized to real-world results. Thus, the panel concluded, the polygraph
is unsuitable to screen for terrorists and other threats because false
positives would lead to many innocent people being wrongly accused and
even then, couldn’t possibly catch everyone with something to hide.
Still, the U.S. government administers thousands of polygraph tests every
year to job applicants and federal employees.
In contrast, most of the new lie detection technologies
are based on a growing understanding of what happens when we prevaricate.
In 2001, in a precursor to Kozel’s work, Sean Spence and his colleagues
at England’s University of Sheffield began using functional magnetic
resonance imaging (fMRI) to localize lying in the brain. Spence asked
volunteer subjects about activities they might have performed, instructing
them to answer some questions truthfully and to lie in response to others.
Lying, it turned out, activated areas of the brain not involved in telling
the truth.
Initially, all such research compiled only average
responses, considering all instances of lying and truth-telling in aggregate
rather than looking at a particular subject’s truthfulness. The
first two studies to focus on individual subjects’ lies were published
last year. One involved Kozel’s experiments, in which subjects “stole” a
ring or watch. The other, by Daniel Langleben of the University of Pennsylvania,
appeared just a few weeks earlier than Kozel’s.
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