"Brain Fingerprints" May Offer Better Way to Detect Lying

Patricia Wen
The Boston Globe
July 5, 2001

Former CIA agent Aldrich Ames easily fooled lie-detector tests, concealing his work as a Russian spy. But could he have duped a "brain fingerprinting'' exam, which probes what people know by checking their electrical brain waves?

Nanny Louise Woodward passed a polygraph, denying that she killed a Newton baby in her charge, though she was later convicted of the crime. Suppose she had put her head in a brain-scanning machine that measures deceit in blood flow patterns?

Then there's John and Patsy Ramsey, who insist lie-detector tests clear them of any role in the death of their 6-year-old girl. But what would happen if a computerized video machine taped their facial expressions for signs of dishonesty?

As polygraphs become increasingly controversial, sparking a cottage industry on how to "beat" the test, scientists are hunting for new high-tech ways of solving the most ancient of human dilemmas: How do you tell if someone is lying?

"I believe it's only a matter of time before we have much better lie-detectors," said Stephen Kosslyn, a Harvard University psychology professor who is studying the brain scans of liars. "The science of this is only going to get better."

Rather than measure signs of stress, such as blood pressure and heart rate, as polygraphs do, many of the new techniques try to get inside the brain itself.

They measure things such as brain waves and cerebral blood flow, which people cannot control—at least not yet. And they're making headway: A judge even admitted some brain-testing results as evidence in an Iowa murder case last March while polygraph evidence is still inadmissible.

Beyond the courtroom, intelligence agencies have been quick to recognize the value of a better truth-detector.

The CIA, scandalized by discoveries of double-crossers within its ranks, is funding much of the lab work, along with science foundations.

The FBI and other law-enforcement groups are hiring some of these scientists as consultants, and asking them to train staff in new techniques.

Although these researchers are confident their technology may prove more accurate than today's polygraphs, they are quick to point out there will never be a magic box that discerns truth with 100 percent accuracy, and all these devices should be seen as supplements to old-fashioned gumshoe work.

Continued on Next Page >>


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