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Brain Scan Lie-Detection Deemed Far From Ready For Courtroom

Publication Date: 
June 01, 2010
Wired Science
Alexis Madrigal

Professor Hank Greely is quoted on the use of fMRI brain scan technology as evidence in the courtroom. Alexis Madrigal of Wired filed this story:

A landmark decision has excluded fMRI lie-detection evidence from a federal court case in Tennessee.

The defense tried to use brain scans of the defendant to prove its client had not intentionally defrauded the government. In a 39-page opinion, Judge Tu Pham provided both a rebuke of this kind of fMRI evidence now, and a roadmap for how future defendants may be able to satisfy the Daubert standard, which governs the admissibility of scientific evidence.


On balance, Hank Greely, Stanford law professor and co-director of the Law and Neuroscience Project, did not find Cephos’ case for its product’s scientific accuracy compelling.

“It seems almost laughable that Cephos could parade this as a great method when, in this very case, they tried it three times and got one result twice and the other one once,” Greely wrote in an e-mail to “In the only ‘real world’ test we’ve got evidence about, their accuracy rate was either 66.7 percent or 33.3 percent.”


Laken’s unwillingness to testify to specific questions — and Pham’s acknowledgment of it — piqued Greely’s interest.

“That’s a really interesting critique of the Cephos method — and one that none of us had really noticed before this testimony because we hadn’t realized that Laken would say that he couldn’t give an opinion on individual questions,” Greely said. “If that’s Laken’s final position, it makes a courtroom use of this technology seem unlikely.”

All-in-all, the decision found multiple instances where fMRI evidence did not meet the standards of evidence in the United States. While that’s a victory for opponents of the use of fMRI in courts, like Greely, it might also offer proponents a clear path to shoring up the use of lie-detection scans.

“There will certainly be further litigation over fMRI lie detection in future cases. I expect that the companies marketing this research for forensic purposes will likely conduct new tests in light of the report recommendation to address some of the articulated weaknesses,” Owen said.