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How Much Sway Should Brain Science Hold Over Court Hearings?

The growing opinion of many experts in both law and neuroscience is that law should not take neuroscience at face value.
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Law should not take neuroscience at face value. At least, that’s the growing opinion of many experts in both fields who worry that the almost magical allure of the brain holds too much sway over contemporary judicial proceedings.

It's a subject that Nita Farahany, a professor of law at Duke and editor of the book The Impact of Behavioral Sciences on Criminal Law, broached at this week’s Society for Neuroscience meeting in California in a talk entitled “Blaming the Brain: Behavioral Sciences in the Courtroom.” Farahany collected and scrutinized 1,500 judicial opinions. Her research, culled from legal activity between the years 2005 and 2012, suggests that the use of behavioral sciences in the legal realm is on the rise. In fact, she said that neuroscience currently plays a role in approximately five percent of murder trials in the United States.


Usually the topic infiltrates the courts via lawyers seeking to devise a potent defense to justify and excuse their client’s behavior or, alternatively, as a means of reducing a sentence. If a defendant has a brain abnormality that can be correlated with an inability to understand one’s actions or a predisposition towards a certain kind of unacceptable behavior, the argument goes that said defendant cannot be held responsible for their actions.

Oftentimes, Farahany says, this sort of reasoning is used when minors are involved. As she told NPR, “It seems like judges are enamored with the adolescent brain science. Large pieces of their opinions are dedicated to citing the neuroscientific studies, talking about brain development, and using that as a justification for treating juveniles differently.”

Our reliance on neuroscience makes sense given our collective assumptions about the brain. We see the organ as the seat of our minds and personalities—that which makes us us and not someone else. So obviously, we jump to the assumption that if our brains are us, then any aspect of our brains that somehow deviates from the norm should be taken into account when reviewing a legal case against us. Sometimes this means a not guilty verdict; other times, it simply means getting two years instead of ten.

The trouble is that actual neuroscience may not bear out our conceptions. Or at least, not in the clear and distinct neuroscience-as-fact, “brain equals person” manner we often imagine.


A two-year old report by The Royal Society outlines several obstacles (pdf) that stand in the way of mapping neuroscience successfully on to law. More generally, there are issues with language and methodology, both disciplines operating in completely distinct settings—lab versus the real world—and speaking different languages.

Specifically, however, the report outlines several major problems at the intersection of law and neuroscience. There’s trouble with the idea of causation: “ideas about causality in neuroscience are not necessarily the same as those that operate in the legal sphere.” Then there’s the problem of reverse inference, which is “the misguided and incorrect attempt to conclude from observation of activity in an area that a particular mental process was taking place.” Also cautioned against is the application of group study findings to individuals. What may be true of a population is not true of every individual in that population.

Beyond examining how the interchange of the legal and the neuro actually works, what of other influences that might predispose us to criminal acts, those outside the boundaries of the biological and neuroscientific? For example, I am just as much a product of the socio-economic background I was born into as I am my brain. Both influences are equally out of my control, so why don’t we give the same amount of heft to someone’s non-biological background as we do to brain scans?

“Most often, it’s not a matter of the brain being qualitatively different from that of other people, and more of the brain reflecting a lifelong accumulation of experiences in which genes interact with the environment in very complex ways,” Jay Gedd, a neurophysicist with the National Institutes of Health, said at a 2011 symposium addressing this topic. “In general, people overvalue the ability of brain imaging or neuroscience to cut through that complexity.”

Relatedly, The Royal Society report states, “the law (as a social practice) still needs to determine which particular antecedents or causes justify, excuse, or mitigate a particular action, and which do not.” In other words, the legal world needs to not only meticulously analyze neuroscience’s role in law, but also that of a network of other influences from the biological to the social.

Ironing out this relationship will not be simple, a truth reflected in the ever-growing numbers of institutes, classes, and publications dedicated to examining the intersection between these two disciplines. And it won’t just be the United States that needs to sort this out. Famous cases around the world, including one in India wherein a woman was found guilty of murdering her fiance because of a brain scan, show how important the nexus between law and science will be in determining the guilty of future defendants.