High-tech truth Latest devices put more people's honesty to the

WASHINGTON -- The world is becoming a trickier place for people who tell lies -- even little white ones.

From thermal-imaging cameras, designed to read guilty eyes, to brain-wave scanners, which essentially watch a lie in motion, the technology of truth-seeking is leaping forward.

At the same time, more people are finding their words put to the test, especially those who work for the government.

FBI agents, themselves subjected to more polygraphs as a result of the Robert Hanssen spy case, have been administering lie detection tests at Fort Detrick, Md., and Dugway Proving Ground in Utah, bases with stores of anthrax. Nuclear plant workers also are getting the tests in greater numbers since Sept. 11.

Scanning the face

The new frontiers of lie detection claim to offer greater reliability than the decades-old polygraph, which measures heart and respiratory rates as a person answers questions.

They also pose new privacy problems, moral dilemmas and the possibility that the average person will unwittingly face a test.

At the Mayo Clinic, researchers hope to perfect a heat-sensing camera that could scan people's faces and find subtle changes associated with lying. In a small study of 20 people, the high-resolution thermal imaging camera detected a faint blushing around the eyes of those who lied.

The technique, still preliminary, could provide a simple and rapid way of scanning people being questioned at airports or border crossings, researchers say.

But would it be legal?

"As long as no one was being arrested or detained solely on the basis of the test, there is no law against scanning someone's face with a device," said Justin Hammerstein, a civil liberties attorney in New York.

"You could use the device to subject someone to greater scrutiny in a physical search or background check, and it would be hard to argue that it is illegal."

'Introducing chaos'

Barry Steinhardt of the American Civil Liberties Union said any technology that isn't 100 percent effective could lead unfairly to innocent travelers being stranded at airports.

"You would be introducing chaos into the situation and inevitably focusing on people who are innocent," Steinhardt said.

At the University of Pennsylvania, researcher Daniel Langleben is using a magnetic resonance imaging machine, the device used to detect tumors, to identify parts of the brain that people use when they lie.

"In the brain, you never get something for nothing," Langleben said. "The process for telling a lie is more complicated than telling the truth, resulting in more neuron activity."

Even for the smoothest-talker, lying is tough work for the brain.

First, the liar must hear the question and process it. Almost by instinct, a liar will first think of the true answer before devising or speaking an already devised false answer.

All that thinking adds up to a lot of electrical signals shooting back and forth. Langleben says the extra thought makes some sections of the brain light up like a bulb when viewed with an MRI.

MRI machines are bulky, but their potential as lie detectors could lead to the invention of smaller, more specialized versions, Langleben said.

Other tests are on the market, although how well they perform is an open question.

Hand-held "voice stress" detectors already are being sold for $300 to $600 at some department stores and on the Internet.

Makers claim the devices show when a person's voice trembles under the stress of a lie. Although skeptics say there is no proof they work, police in Philadelphia, Los Angeles and Miami are using more advanced versions and say they sometimes prompt confessions.

Not everyone is sold on it.

"Voices can shake because people are scared about being interrogated by police," said Thomas Jakes, president of People for Civil Rights. "This technology is nothing but a way to scare people."