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Andrea Harner
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April 10, 2007

The Brain on the Stand by Jeffrey Rosen


This article from the NYT magazine is a few weeks old but really interesting and asks the huge question: How does and should neuroscience affect criminal law?

From a ton of worthy excerpts I've whittled it down to these:

One important question raised by the Roper case was the question of where to draw the line in considering neuroscience evidence as a legal mitigation or excuse. Should courts be in the business of deciding when to mitigate someone’s criminal responsibility because his brain functions improperly, whether because of age, in-born defects or trauma? As we learn more about criminals’ brains, will we have to redefine our most basic ideas of justice?

Two of the most ardent supporters of the claim that neuroscience requires the redefinition of guilt and punishment are Joshua D. Greene, an assistant professor of psychology at Harvard, and Jonathan D. Cohen, a professor of psychology who directs the neuroscience program at Princeton. Greene got Cohen interested in the legal implications of neuroscience, and together they conducted a series of experiments exploring how people’s brains react to moral dilemmas involving life and death. In particular, they wanted to test people’s responses in the f.M.R.I. scanner to variations of the famous trolley problem, which philosophers have been arguing about for decades.

The trolley problem goes something like this: Imagine a train heading toward five people who are going to die if you don’t do anything. If you hit a switch, the train veers onto a side track and kills another person. Most people confronted with this scenario say it’s O.K. to hit the switch. By contrast, imagine that you’re standing on a footbridge that spans the train tracks, and the only way you can save the five people is to push an obese man standing next to you off the footbridge so that his body stops the train. Under these circumstances, most people say it’s not O.K. to kill one person to save five.

“I wondered why people have such clear intuitions,” Greene told me, “and the core idea was to confront people with these two cases in the scanner and see if we got more of an emotional response in one case and reasoned response in the other.” As it turns out, that’s precisely what happened: Greene and Cohen found that the brain region associated with deliberate problem solving and self-control, the dorsolateral prefrontal cortex, was especially active when subjects confronted the first trolley hypothetical, in which most of them made a utilitarian judgment about how to save the greatest number of lives. By contrast, emotional centers in the brain were more active when subjects confronted the second trolley hypothetical, in which they tended to recoil at the idea of personally harming an individual, even under such wrenching circumstances. “This suggests that moral judgment is not a single thing; it’s intuitive emotional responses and then cognitive responses that are duking it out,” Greene said.

“To a neuroscientist, you are your brain; nothing causes your behavior other than the operations of your brain,” Greene says. “If that’s right, it radically changes the way we think about the law. The official line in the law is all that matters is whether you’re rational, but you can have someone who is totally rational but whose strings are being pulled by something beyond his control.” In other words, even someone who has the illusion of making a free and rational choice between soup and salad may be deluding himself, since the choice of salad over soup is ultimately predestined by forces hard-wired in his brain. Greene insists that this insight means that the criminal-justice system should abandon the idea of retribution — the idea that bad people should be punished because they have freely chosen to act immorally — which has been the focus of American criminal law since the 1970s, when rehabilitation went out of fashion. Instead, Greene says, the law should focus on deterring future harms. In some cases, he supposes, this might mean lighter punishments. “If it’s really true that we don’t get any prevention bang from our punishment buck when we punish that person, then it’s not worth punishing that person,” he says. (On the other hand, Carter Snead, the Notre Dame scholar, maintains that capital defendants who are not considered fully blameworthy under current rules could be executed more readily under a system that focused on preventing future harms.)

Morse insists that “brains do not commit crimes; people commit crimes” — a conclusion he suggests has been ignored by advocates who, “infected and inflamed by stunning advances in our understanding of the brain . . . all too often make moral and legal claims that the new neuroscience . . . cannot sustain.” He calls this “brain overclaim syndrome” and cites as an example the neuroscience briefs filed in the Supreme Court case Roper v. Simmons to question the juvenile death penalty. “What did the neuroscience add?” he asks. If adolescent brains caused all adolescent behavior, “we would expect the rates of homicide to be the same for 16- and 17-year-olds everywhere in the world — their brains are alike — but in fact, the homicide rates of Danish and Finnish youths are very different than American youths.” Morse agrees that our brains bring about our behavior — “I’m a thoroughgoing materialist, who believes that all mental and behavioral activity is the causal product of physical events in the brain” — but he disagrees that the law should excuse certain kinds of criminal conduct as a result. “It’s a total non sequitur,” he says. “So what if there’s biological causation? Causation can’t be an excuse for someone who believes that responsibility is possible. Since all behavior is caused, this would mean all behavior has to be excused.” Morse cites the case of Charles Whitman, a man who, in 1966, killed his wife and his mother, then climbed up a tower at the University of Texas and shot and killed 13 more people before being shot by police officers. Whitman was discovered after an autopsy to have a tumor that was putting pressure on his amygdala. “Even if his amygdala made him more angry and volatile, since when are anger and volatility excusing conditions?” Morse asks. “Some people are angry because they had bad mommies and daddies and others because their amygdalas are mucked up. The question is: When should anger be an excusing condition?”

The experiments, conducted by Elizabeth Phelps, who teaches psychology at New York University, combine brain scans with a behavioral test known as the Implicit Association Test, or I.A.T., as well as physiological tests of the startle reflex. The I.A.T. flashes pictures of black and white faces at you and asks you to associate various adjectives with the faces. Repeated tests have shown that white subjects take longer to respond when they’re asked to associate black faces with positive adjectives and white faces with negative adjectives than vice versa, and this is said to be an implicit measure of unconscious racism. Phelps and her colleagues added neurological evidence to this insight by scanning the brains and testing the startle reflexes of white undergraduates at Yale before they took the I.A.T. She found that the subjects who showed the most unconscious bias on the I.A.T. also had the highest activation in their amygdalas — a center of threat perception — when unfamiliar black faces were flashed at them in the scanner. By contrast, when subjects were shown pictures of familiar black and white figures — like Denzel Washington, Martin Luther King Jr. and Conan O’Brien — there was no jump in amygdala activity.

“Will we use brain imaging to track kids in school because we’ve discovered that certain brain function or morphology suggests aptitude?” he asks. “I work for NASA, and imagine how helpful it might be for NASA if it could scan your brain to discover whether you have a good enough spatial sense to be a pilot.” Wolpe says that brain imaging might eventually be used to decide if someone is a worthy foster or adoptive parent — a history of major depression and cocaine abuse can leave telltale signs on the brain, for example, and future studies might find parts of the brain that correspond to nurturing and caring.

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