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Complex Brain Imaging Is Making Waves In Court

Publication Date: 
October 17, 2008
San Francisco Chronicle
Reyhan Harmanci

The San Francisco Chronicle quotes Professor Hank Greely in a story about brain imaging as a means of determining guilt or innocence in the courts:

"The law is mainly about brains or, at least, the mind," said Stanford law Professor Hank Greely, one of the directors of the year-old MacArthur Foundation-funded Law and Neuroscience Project. "If my fist hits your chin, what, if anything, I was thinking is crucial. If I was in an epileptic fit, if I was thrown from a car when I hit you, you don't convict me of a crime. ... If I'm mad at you, we do."

The degree to which brain scans will be admissible in court remains unclear, but experts already are pointing to precedent-setting cases and warning that neuroscience could alter the law, creating new methods and new visual evidence to determine criminal intent and criminal responsibility.

Greely, 56, who directs both the law school's Center for Law and the Biosciences and the neuroethics program at the Stanford Center for Biomedical Ethics, has led the charge to make sure advances in neuroscientific research are applied cautiously to the legal realm.

"Neuroscience has some real potential to be used as important evidence in cases and give broader insights into the law," he said. "It also has the real potential to be misused. If it's applied too early, it can lead to bad results."

The law is as vulnerable to faulty cultural and scientific thinking as any other field, which is why Greely calls for vigilance in neuroscience. In the 20th century, eugenicists who sought to "improve" the American population by weeding out bad hereditary characteristics convinced courts to uphold bad policies like the sterilization of the mentally retarded. Phrenology, a quack science whereby the shape of people's skulls was thought to reveal their personality, was heralded by scientists and criminologists in the mid-19th century as way to predict criminal behavior.


"Some things we know how to detect on a scan. If your visual cortex is destroyed by a stroke, you won't be able to see. If your Broca's region is destroyed, you won't be able to talk," Greely said. "That's what makes (neuroimaging) such a tease - we've known a few of these (functions) for a long time, but for most behavior we just don't know what's going on in the brain."


"It's unclear how often brain scans appear in trial - definitely, they appear from time to time," Greely said. He is creating a database of scan appearances in California courts.


"I am very nervous about unproven lie detection," said Greely, who nonetheless believes Cephos' method will be admissible to court in five years or less because individual judges are unpredictable.

...Greely and Wolpe agree that there is "little doubt" the U.S. government has been studying them. "We have a technology now that, under certain circumstances and in certain ways, allows us to look at activities of the brain and deduce things that previously we never could have understood from a person without communicating with them," Wolpe said. "This raises new questions about how this technology should be used, and by whom."