Neuroscience and the Law

Much of what we “know” from neuroscience research is not ready—yet—for use in the courtroom, argued panelists during a forum on Thursday in Washington, DC.

“We’re not at the stage where we can accuse or convict—or determine a sentence” using only brain data, said Steven Hyman, director of the Broad Institute of MIT and Harvard and a Dana Foundation board member, during a Neuroscience and Society session at the American Association for the Advancement of Science (AAAS).

For example, “To be guilty, you have to have a ‘criminal mind,’ mens rea, the ability to form criminal intent,” Hyman said.”The law is fairly subtle about this,” distinguishing if a mindset is cold and calculating, or reckless, or merely negligent. “Mindset really matters,” he said. “But here’s the problem: We don’t have access to people’s mental states, and people lie all the time.”

Sometimes the lies are conscious, but we also “lie” to ourselves, explaining away mistakes in our behavior and changing our storylines to suit our needs. “We’re always updating our memories and interpretations… to be aligned in our favor,” Hyman said. So researchers are looking for something objective, physical predictors like biomarkers that could show mental state.

That’s not so easy. “Except for rare, severe syndromes, behavior is the product of many genes, brain development, chance, experience, and context,” Hyman said. For example, scientists have already found 90 genes that contribute to the risk a person will develop schizophrenia, and it’s still early days in genetics research.

“I believe that our behavior is based on the activity of our brains,” Hyman said, but “I can’t tell what are the causal factors in that individual.” Was it a snip in a gene, an event in his childhood, something he read a moment ago?

“If my brain made me do it, I did it,” Hyman said. “But if you say, ‘this spot on my brain did it,’ that’s the fallacy. If you’re blaming your brain, you might as well be looking in a mirror.”

But the temptation is so strong, said Owen Jones, director of the MacArthur Foundation Research Network on Law and Neuroscience and a law professor at Vanderbilt University.

“We don’t have direct access to mental states, but mental states are so critical to [questions of] the law,” he said. Lawyers, judges, and juries need to assess what’s going on in people’s brains to decide such questions as whether they are competent to stand trial or to handle their own finances, if they are being truthful, if their memories are correct, if they will be violent again.

And even when it’s clear a person has some psychiatric or anatomical brain anomaly, that doesn’t prove the anomaly is what caused him to commit a particular crime: “Even people with serious mental problems don’t go around stabbing their girlfriend 61 times,” as one man did in a recent court case.

Courts and lawyers need to distinguish when data is from an individual, and when it is from a group, as most brain research is. What is true for a group, especially if the data is averaged, is very likely not true for a single member of the group, or for someone else (an accused person) who wasn’t in the group to begin with.

Judge Barbara Rothstein agreed. “Science comes into the courtroom in the context of a particular case; there’s no interest in science as a philosophical pursuit,” said Rothstein, U.S. District Judge from the Western District of Washington state. Court is an adversarial setting, and the lawyers’ jobs are to win the case. Even if a study looked at a thousand people, “what value does it have to a particular individual, a particular case?”

“When you have a jury awarding damages to a plaintiff who is a psychic and alleges that she lost her psychic power…and the jury gives her damages for loss of future income, that’s a reason to worry about the science that’s coming into the  courtroom,” Rothstein said.

Judges act as gatekeepers for technology and science; they must rule on whether a jury will even hear hard-science testimony from experts. While judges didn’t go to school to learn science, “Here we are, by some cruel twist of fate, not only having to look at science, but to look at cutting-edge science,” Rothstein said.

How do they learn it? “By listening to the experts that come in front of us,” and who have an agenda. “And our ruling is important—it’s whether the expert can speak to the jury,” which can mean the end of the case if the plaintiff’s experts are rejected.

Judges and juries are skilled at “reading” people and weighing what they say; it’s what we do as humans every day. But what’s new in neuroscience testimony is the idea that this is Data, with a big “D,” irrefutable.

“What we rely on for predictability are psychiatrists’ reports, interviews, psychiatric testing,” Rothstein said. “We’ve never had someone say to us before, ‘No no no, don’t listen to those experts, it’s physiologic, it’s in the brain, it’s undeniable, look.’”

For now, in the federal courts at least, the judges aren’t buying it. “Unlike DNA, neuroscience is reaching the courts in a premature state,” Rothstein said. There was consensus among experts that DNA-testing worked and how it worked, and there is no such consensus on what brain images or other neuro-research shows. “The courts are sensitive enough to that,” she said. For example, “When you have a group called ‘No Lie MRI,’ it somehow doesn’t have the ring of authenticity.”

All three panelists said they expected neuroscience results to keep pushing their way into the courts, and eventually to be accepted and have an impact. It likely will start small, Jones suggested, as an example of something that contributes to the causes, not *the* single cause. It could serve a “buttress function, triangulating with other information that we know, adding weight” toward one side of the case or the other.

If you want to keep up with news and research on issues of law and neuroscience, Jones runs, which posts current news and also has a searchable database of cases and research.

The event was recorded; we’ll post a video soon on The next sessions this year in the Neuroscience and Society series are on the adolescent brain, human enhancement, and the brain and the arts. The series is supported by the AAAS Scientific Responsibility, Human Rights, and Law Program and by the Dana Foundation. This event also was sponsored by The International Neuroethics Society and the MacArthur Foundation Research Network on Law and Neuroscience.

UPDATE: A webcast of the event is now on

– Nicky Penttila

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