A man may learn wisdom even from a foe. - Aristophanes
For 5,000 dollars, a computer will scan your brain several times while asking you a series of banal yes or no questions: Do you live in Texas? Is it 2009? It will also ask you one important question, such as: Did you burn down the shop? Or, have you cheated on your spouse? Shortly thereafter, it will spit out two numbers. And the creators of the test insist that those two numbers will determine if, when you answered the serious question, you were lying.
This method of lie detection, which relies on brain scans rather than a racing heart, still hasn’t gained widespread support among mainstream neuroscientists or the legal community. But two companies, Cephos Corporation in Tyngsboro, Massachusetts, and No Lie MRI in San Diego,California, are already marketing it to clients, at a time when many experts worry about the technique’s accuracy in detecting real-life lies, as opposed to the fibs conjured up by study volunteers in experiments. And even if the test is reliable, experts question whether the results of this sort of mind reading should be admissible in court.
But many neuroscientists and legal scholars say the evidence isn’t ready for the courtroom. Judy Illes, a neuroethicist at the University of British Columbiain Vancouver, calls the companies “premature” and says “I don’t think we have the scientific evidence yet to be selling fMRI for the kind of applications they are supporting. . . . It’s a tall order to be able to sell results.”
Cephos’ test relies on functional magnetic resonance imaging (fMRI), a technology that measures changes in blood flow to different areas of the brain over time. Working neurons require more oxygen and thus more blood, just as working muscles do, so by tracking blood flow, fMRI shows which areas of the brain are most active at any particular moment.
Many fMRI studies have concluded that a few key areas of the brain are more active during deception than truth-telling. These include the anterior cingulate cortex, which is involved in attention and monitoring processes, and the left dorsolateral and right anterior prefrontal cortices, areas of executive function involved in working memory and behavioral control.
If prosecutors try to get the results of fMRI lie detection tests admitted into court, they can expect a challenge based on the Constitution’s ban on self-incriminating testimony, according to Kenneth Foster, a bioengineer who is also associated with the University of Pennsylvania’s neuroethics program.
“Legally, is having a brain scan similar to a urine sample or similar to testifying?” Foster asks. If it’s considered testimony, then defendants could challenge it by citing their Fifth Amendment rights. “This kind of dilemma has to be solved soon because it’ll make a big difference in the way courts see the admissibility of this evidence.”