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True Lies

Publication Date: 
October 01, 2009
ABA Journal
Mark Hansen

Professor Hank Greely, an expert in biotechnology law, is quoted in the ABA Journal on the reliability and effectiveness of new lie detection technologies:

I am a terrorist. At least that’s what I’ve been told to be, as I’m sitting at a computer in the lab adjacent to J. Peter Rosenfeld’s cluttered second-floor office in the psychology department on Northwestern University’s leafy campus.

Electrodes are attached to my scalp, behind each ear, above and below my left eye, and in the middle of my forehead.

I’m thinking about how I can lay waste to the city of Houston. Or rather, trying not to think about it. After all, I am a terrorist; and I’m trying to conceal the fact that I want to lay waste to the nation’s fourth-largest city.

Rosenfeld, who for 20 years has been studying brain wave activity as a means of detecting deception, has been describing a new test protocol he has designed to catch terrorists before they can execute a planned attack. And when he offered me a chance to be tested, I said, “Hook me up.”

The premise of the test is that a suspect who knows details of the plan—the location, the method and the timing—will emit a telltale response from brain waves when presented with information that coincides with those details, no matter how hard the suspect tries to conceal it.


“Because the MRI is a big, fancy machine that produces these beautiful color pictures, there’s a fear that people might be overly impressed by the technology and take it more seriously than they should,” says Hank Greely, a professor of law and genetics at Stan­ford University who also heads the law school’s Center for Law and the Biosciences.

“On the other hand, because the EEG only produces an image of a brain wave, people may not give it the attention it deserves, even though at this point, we don’t know which technique, if either, will ever be effective at lie detection.”


“The scientific research on it has been universally negative,” Greely says.

Though voice stress analysis is apparently quite popular among law enforcement agencies, that seems to have more to do with the fact that it is relatively inexpensive and can be quite intimidating than with its ability to detect lying, experts say.

“It’s pretty good at telling whether somebody is nervous or not, but a lot of people get nervous when they’re talking to the police,” Greely says.


“Just because you recognize Osama bin Laden doesn’t mean you spent time in an al-Qaida training camp with him,” Greely says. “Maybe you just saw his picture on TV or the cover of a magazine.”


But critics are highly dubious. Greely says all anyone has seen of the technique is the inventor’s own bro­chure. “I’ve yet to meet anybody who has any idea how what they claim to be doing would be possible,” he says.


Greely, who co-authored a 2007 study that found “very little” in the peer-reviewed literature to suggest that fMRI-based lie detection might be useful in real-word situations, says he hasn’t seen anything since then that would change his mind.

“At this point, we just don’t know how well these methods will work with diverse subjects in real-world situations, with or without the use of countermeasures,” he says.


Greely says nobody but the in­ventors seems to be working on the technology. And the National Research Council, in a 2002 report on the poly­graph and other lie detection technologies, called the testing to date a “flawed and incomplete evaluation” that “does not provide acceptable scientific evidence” to support its use in detecting deception.


“There is no way of knowing how much of that is being spent on what,” Greely says, “but it’s safe to say that a lot of money is going into neuroscience-based deception research, which the defense services have long had an interest in.”


Greely proposes a pre-market approval process sim­ilar to that used by the Food and Drug Administration in its governing of the introduction of new drugs.

“We need to prevent the use of unreliable tech­nologies and develop fully detailed information about the limits of accuracy of even reliable lie detection,” he says. “Otherwise, honest people may be treated unfairly based on negative tests; dishonest people may go free.”