While Washington Post writer Joel Garreau may be right that the 10-foot-tall, 14-ton “functional magnetic resonance imaging” machine “promises to be the most formidable lie detector ever built,” that doesn’t make it useful in the real world. It certainly is large, noisy and a bit scary, but its pictures show differences so deep among people that it’s nowhere near clear who is telling fibs, tall tales or whoppers.
“We’ve grown up in the last 15 years thinking when we see one of these scans that they finally have figured out the brain circuits involved,” said Michael Gazzaniga during a neuroethics symposium at the Library of Congress that we co-sponsored in May 2005. “But it turns out those are averages—and the individual variations are huge.”
“Imagine the neuroscientist comes into the courtroom and says, ‘Look, this pixel in the brain here is lit up and so therefore Harry didn’t kill the person.’ But the other side will simply have to point to the variation in the response” and the judge would throw the evidence out, as now is done with most lie-detector evidence.
Garreau’s experience inside the fMRI makes Gazzinga’s point. Some of his lies made brain-pictures that looked like lies, but one whopper registered as the “truth.” That got the researchers excited and more curious, but it should give the lawyers—and the rest of us—pause.
— Nicky Penttila