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Nov 14, 2006 9:24 pm US/Central
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Lies Only A Brain Scan Away From Being Detected
New Generation Of Lie Detector Tests Rely On Brain Signals Rather Than Body Clues
by Mary Ann Childers
CHICAGO (CBS) ―
There is a new way to tell if someone is lying, or telling the truth.
They are lie detectors. But not the kind you think. CBS 2's Medical Editor Mary Ann Childers reports these are truth tests that measure changes in your brain.
Polygraphs are about 70 percent accurate. They measure irregular breathing, pulse rate, sweating -- what happens to your body when you are asked questions. The new tests measure what happens in your brain.
"When you are lying, you are trying to block the truth from coming out. So it's a conscious, voluntary process," said Dr. K. Luan Phan, a psychiatrist at the
University of Chicago.
Lying causes changes in your brain that you can see with a
functional MRI because lying makes your brain work harder in the pre-frontal cortex, where reasoning occurs. The degree of brain activity varies with the individual, but the area involved is always the same.
"What you can see is that there is a lot more activation occurring when a person is lying than when they're telling the truth," said Steve Lakin of the Cephos Corporation.
Lakin claims this test is 90 percent accurate, and his Massachusetts-based company hopes to market it in the next two years. A California company, "No-Lie MRI," just started offering the test.
There are problems, however. MRI systems cost more than $1million. You have to hold your head perfectly still in the machine as you answer questions. And you can beat the machine -- if you can do one thing:
"You can convince yourself you're telling the truth," Phan said.
If you really believe something is true, your brain won't register enough changes to be conclusive.
"You are not going to find an MRI in every police department anytime soon," said Peter Rosenfeld, Ph.D., a psychologist at
Northwestern University.
But Rosenfeld is researching a test you might see more widely. It's not a scan, but an EEG that measures brain waves. The waves intensify -- for milliseconds -- the instant our brains recognize something that makes us feel threatened or guilty.
"Certainly we can identify information about you that you would want to keep secret," said Rosenfeld.
Rosenfeld says his brain wave test is between 90 percent and 100 percent accurate. And the test is hard to fake or beat because even if you believe the lie, your brain, even if just for a millisecond, will recognize it.
So far, MRI truth tests have only been done on cooperative subjects. But Rosenfeld's brain wave tests are going to be tried on real criminals.
Next year, Northwestern University is going to begin a study supported by a major security agency that is not being identified. They will test not only brain waves, but also such things as pupil size; it will include lasers that check your pulse without you knowing it, measure body temperature changes and some other things Rosenfeld says even he doesn't know about yet.
(© MMVI, CBS Broadcasting Inc. All Rights Reserved.)