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Allowing brain scan data into legal proceedings too quickly could be dangerous, prominent scholars warn

Panelists discuss the intersection of law and neuroscience. Photography by Norbert von der Groeben.

Stanford, Calif., October 3, 2013 - Leading researchers in law and neuroscience gathered at Stanford on Wednesday night to review the developing relationship between the two fields and cautioned that prematurely welcoming brain science into the legal system could have perilous consequences. “Brains on Trial” was presented by Stanford Law School’s Center for Law and the Biosciences (CLB) and moderated by renowned actor and science educator Alan Alda. Alda recently hosted the acclaimed PBS series of the same name (click here to visit the series’ website).

The focus of the discussion was how the overlap between law and neuroscience could affect individual rights and the reputations of both disciplines. Panelists included Silvia Bunge, professor of psychology at University of California, Berkeley*; Hank Greely, professor of law at Stanford Law School and director of the CLB; Robert Sapolsky, professor of biology at Stanford; and Anthony Wagner, professor of psychology at Stanford. Click here for a slideshow of the event.

Alda’s initial comments helped frame the evening, as he stated that the purpose of the discussion was to “explore brain science’s growing ability to peer inside our head” and how this science can influence the justice system.

The discussion then turned to what Alda called “one of the most immediately controversial” questions about brain science—the ability to detect a lie. The panel described how functional magnetic resonance imaging (fMRI), which uses changes in blood flow to detect brain activity, is being advertised as a reliable method of lie detection.

But the panelists expressed skepticism about the actual reliability of fMRI technology to detect lies. Wagner acknowledged that many controlled experiments involving fMRI scans and lie detection appear to be highly successful, but called these studies “fundamentally flawed” because any detected brain activity might result from triggers other than deception.

“We need to do better science,” Wagner contended.

Greely explained that judges have generally rejected efforts to introduce fMRI scans as evidence of deception because of concerns about the scientific validity of fMRI technology for the purpose of lie detection.

“My own view,” Greely said, “is [that] it’s not ready to be used in court.”

Alda pursued the topic by asking when fMRI technology would be ready for admission in court as a dependable means of lie detection. Greely cautioned the audience to consider two issues. Calling for robust and long-term scientific trials, Greely emphasized that the accuracy of this technology as a means of lie detection must be demonstrated first.

But assuming that such accuracy can be demonstrated, Greely warned that the next question is how to use the technology. Observing that fMRI scans are currently voluntary, Greely asked the more provocative question: “Could we get a search warrant to search your brain?”

The panelists were equally apprehensive about using neuroscience to confirm the reliability of eyewitness testimony. Explaining that brain scans can indicate whether a person recognizes a particular image, such as a face, Wagner added that such results appear even when the image is novel.

“We’ve known for … about 30 years now that there are multiple forms of memory,” Wagner said, clarifying that some memories are simply “residues, traces in the brain of past experience.”

Alda then broached the constitutionality of applying neuroscience to the justice system, or as he phrased it, “getting a person’s brain to testify against the person.” Greely recognized that the involvement of neuroscience in the legal system raises “very serious questions” about constitutional rights. Greely advised that current legal protections might be insufficient to protect “cognitive liberty” and “keep private what’s inside our skulls.”

As the panel queried how neuroscience can be used to develop appropriate sentences for juvenile defendants, whose brains are still developing, Bunge said that juvenile sentencing is “a critical issue.” Arguing that negative influences and experiences in the prison environment can significantly harm a developing brain, Bunge cited strong evidence that the juvenile brain can still be shaped.

“Rehabilitation has become a bad word in the legal system,” Bunge argued, but this is “an area where neuroscience is helping to lead the way.”

Bunge added that when rehabilitation is attempted, scientists often see changes in the brain before they see changes in behavior. She called this dynamic “the canary in the coal mine.”

Sapolsky lamented that society often creates a false distinction between the mind and the brain. Asserting that people often view “raw smarts” as somehow more intrinsically biological than abilities such as willpower, impulse control and emotional regulation, he declared that “the whole notion of culpability in the legal system is incompatible with neuroscience.”

Sapolsky added that while the legal world is a dichotomy of guilt or innocence, there is “nothing in the nervous system that does not work on a continuum.” He offered that when a car’s brakes no longer function, the car must be removed from the road. “This is not a moral judgment, but an operational one,” Sapolsky argued.

While the panelists expressed serious reservations about the interplay between the legal system and developments in neuroscience, they also sounded a tone of optimism at times.

Scientists “hope that there are many applications of neuroscience that will benefit society,” Wagner noted.

And while Greely conceded that it can be challenging for attorneys and scientists to fully grasp each other’s areas of practice, he praised Stanford’s “wonderful history of interdisciplinary work” and proposed that “the best thing we can do is to get [these] two groups talking to each other and understanding each other.”

The evening event was sponsored by the Stanford Center for Law and the Biosciences and the Stanford Interdisciplinary Group on Neuroscience and Society.

About The Center for Law and the Biosciences The Center for Law and the Biosciences (CLB), directed by Deane F. and Kate Edelman Johnson Professor of Law Hank Greely, examines biotechnology discoveries in the context of the law, weighing their impact on society and the law’s role in shaping that impact. CLB is part of the Stanford Program in Law, Science & Technology. Situated in the locus of the world’s biotechnology industry, within a preeminent research university, CLB convenes a forum of academicians, lawyers, scientists, policy makers, and law students. Through conferences, workshops, lectures, and academic courses, CLB promotes research and public discourse on the ethical, legal, scientific, economic, and social implications of accelerated technological change.

About Stanford Law School Stanford Law School (www.law.stanford.edu) is one of the nation’s leading institutions for legal scholarship and education. Its alumni are among the most influential decision makers in law, politics, business, and high technology. Faculty members argue before the Supreme Court, testify before Congress, produce outstanding legal scholarship and empirical analysis, and contribute regularly to the nation’s press as legal and policy experts. Stanford Law School has established a new model for legal education that provides rigorous interdisciplinary training, hands-on experience, global perspective, and focus on public service, spearheading a movement for change.

* This story was revised on Oct. 9, 2013, to reflect a change in circumstances. After this story was first published, Silvia Bunge informed the Stanford Graduate School of Education that she would no longer be joining its faculty next year.

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