Criminal Culpability

Michael Gazzaniga’s book “The Ethical Brain,” (is) an examination of how advances in neuroscience are shaping our understanding of moral and legal choices. Though the National Institutes of Health are putting money into neuroscience, and leading scholars in areas ranging from economics to political science are studying brain activity, a good general interest book about neuroscience has yet to be published, making Gazzaniga’s book welcome and well-timed. Recent pieces in The New York Times have declared that love and the allure of Coca-Cola can both be understood through breakthroughs in neuroscience. But Gazzaniga has a particular interest in the law. He believes that some day our understanding of neuroscience “will dominate the entire legal system.”

Gazzaniga, a professor at Dartmouth and a member of President George W. Bush’s bioethics council, covers a lot of ground in his slim volume, including topics like when brains start functioning (somewhere in the second trimester of a mother’s pregnancy), the possibility that parents will someday be able to choose specific character traits for their children (it’s likely), and whether brain imaging can determine whether people are lying (not yet). Gazzaniga’s most interesting chapter, however, centers on the question of where criminal culpability begins and ends.

Neuroscientists are only now beginning to understand the processes of the brain, but, as advances continue, Gazzaniga predicts that neuroscientists are going to find themselves in the middle of legal debates more and more frequently. For example, in the case of the Virginia man in the Archives of Neurology article, a defect in the function of the man’s brain caused by his tumor seems to have been the cause of his criminal actions. As our knowledge of brain function grows, Gazzaniga believes similar exculpatory arguments will begin showing up in courtrooms—and in less cut-and-dried cases.

He notes, for example, that neuroscientists are beginning to grasp the role that individual genes play in building our brains. A criminal with an anger problem, Gazzaniga warns, may soon be able to blame his grandfather’s DNA. Gazzaniga also draws on his own scientific research, which revolves around self-deception. Our brains want things to make sense, so much so that they feed stories to our conscious minds in order to reconcile inconsistent information or memories. This research may do more than deliver another body blow to eyewitnesses, who have been under attack by psychologists for decades on the grounds that they remember what they want to have seen rather than what they saw. It might also foster arguments that defendants were effectively rendered temporarily insane by their lying brains.

Gazzaniga celebrates the science behind these advances, but he’s fearful of how they might be misused in a court of law. “Defense lawyers,” Gazzaniga writes, “are looking for that one pixel in their client’s brain scan that shows an abnormality, a predisposition to crime or a malfunction in normal inhibitory networks, thereby allowing for the argument, ‘Harry didn’t do it. His brain did it. Harry is not responsible for his actions.’ ” Such statements may make it seem as if Gazzaniga has too low an opinion of lawyers and perhaps too high an opinion of science. But consider the experience of Russell Swerdlow, one of the doctors who examined the Virginia man. Lawyers have since approached Swerdlow several times, asking for his help in finding exculpatory evidence in the brain scans of their clients. He has yet to take on a case, but only because he’s yet to find one where a tumor plausibly changed a defendant’s brain. The first lawyer who approached him had a client with a prostate tumor.

IN ANGLO-AMERICAN LAW, the control that a perpetrator had over his actions has been a crucial element in determining punishment, at least since 1843, when the British House of Lords said that a defendant could be declared not guilty by reason of insanity if, at the time of committing a crime because of a “disease of mind,” he didn’t know right from wrong. The premise, then and now, is that under those circumstances, a person shouldn’t be held criminally responsible or morally blameworthy for unlawful acts he commits. The defense has been famously, and successfully, invoked by defendants ranging from John Hinckley, who shot President Ronald Reagan in 1981, to Lorena Bobbitt, who lopped off her husband’s penis a decade ago.

Proving that a defendant was insane, and thus did not have control over his actions, has traditionally been an arduous and subjective process. One study of patients in the early 1990s revealed that less than 1 percent of defendants invoked the insanity defense, and fewer than a quarter of them succeeded. Since the 1980s, courts have admitted into evidence PET and CT scans of the brain indicating that defendants have characteristics of people suffering from mental illness. Gazzaniga believes that advances in neuroscience are about to move far beyond these technologies, thus making such evidence more prevalent, and more persuasive as well. Neuroscience, Gazzaniga believes, will make such a defense far easier to construct by providing a menu of objective and demonstrable explanations for why someone might have committed a crime. Lawyers will be able to point to tumors, irregularities in brain chemistry, or even the existence of particular genes, and they’ll demand leniency on the ground that their client really didn’t have control over whether he committed a crime.

Gazzaniga is troubled by the prospect of lawyers using brain maladies as an all-purpose defense and insisting that their clients lacked the mens rea, or guilty mind, necessary to be convicted. Despite advances in our understanding of the brain and its malfunctions, Gazzaniga argues, the mind can still be guilty.

He notes that most people with brain damage or defects have some ability to restrain their actions. Gazzaniga is convinced that there is a difference between brain and mind—and, in his conception, the mind almost always has veto power over what the brain decides. He calls this capacity “free won’t” and he backs up his view by citing brain studies that show that people make decisions before actually carrying them out. Your brain decides to punch someone before your fist moves. In the meantime your mind has the power to stop the operation.

Gazzaniga also points out that even the brain changes that we know can influence crime aren’t dispositive. Here he cites the example of antisocial personality disorder, which is associated with problems in the prefrontal cortex, the area of the Charlottesville man’s brain that was damaged by his tumor. A more famous case is that of Phineas Gage, a railroad worker whose prefrontal cortex was destroyed by a tamping iron in an accident. Afterward, his appearance stayed the same and his memories remained intact, but his personality was turned upside down. After the accident Gage lost the ability (or desire) to plan ahead and he would swear and talk about sex at inappropriate times.

But while the unbecoming traits brought on by his injury cost Gage his job at the railroad, they didn’t turn him into a criminal. Damage of the type Gage suffered does seem to change a patient’s personality—but it doesn’t necessarily lead to impulsive, much less criminal, action. “Most patients who suffer from Gage-type lesions involving the inferior orbital frontal lobe do not exhibit antisocial behavior of a type that would be noticed by the law,” writes Gazzaniga.

Ultimately, Gazzaniga’s enthusiasm and wonder at the advances of neuroscience are tempered by his strong belief that while many questions can be answered by science, others must be resolved by society and the law. Responsibility, he notes, is a social idea—one that scientists can inform, but can’t define. “The idea of responsibility, a social construct that exists in the rules of a society, does not exist in the neuronal structures of the brain,” Gazzaniga writes. “Just as optometrists can tell us how much vision a person has (20/20 or 20/40 or 20/200) but cannot tell us when someone is legally blind or has too little vision to drive a school bus, so psychiatrists and brain scientists might be able to tell us what someone’s mental state or brain condition is but cannot tell us (without being arbitrary) when someone has too little control to be held responsible.”

GAZZANIGA IS RIGHT TO BE CIRCUMSPECT about the possible misuses of the advances he describes. He is so cautious, however, as to seem almost blind to the benefits that neuroscience could soon bring to the criminal justice system.

Consider, again, the case of the Charlottesville man. Gazzaniga doesn’t examine this example in The Ethical Brain, but it seems clear that he would want the man locked up. Most men with brain tumors don’t become pedophiles, Gazzaniga would point out, and the man’s only defense was, essentially, “my brain made me do it.” It’s just the sort of case that Gazzaniga wants to keep neuroscientists away from.

Think of how neuroscience could inform the punishment meted out in this case, however. Imagine that the man was facing a jury trial for having molested his stepdaughter. Excluding neuroscientists from the courtroom would mean that the man would probably get thrown in prison, put on a list of sex offenders once he was released, and forever banned from living near a school.

If neuroscientists were allowed in the courtroom and were given the chance to explain how the tumor affected the man’s ability to resist urges—to explain this example of matter over mind—he’d probably be treated very differently. He’d face some penalty—the victim likely would want vengeance no matter how much the tumor determined the man’s actions, and in America today, vengeance is considered a legitimate goal of the criminal justice system. (This is one reason why people declared innocent because of the insanity defense are still kept in forensic wards, even if they are deemed not to be a threat to society.) But there wouldn’t be any need to rehabilitate him or to deter him, the other two justifications given for criminal punishment. To stop the activity, he’d just need some form of medical monitoring to make sure that the tumor didn’t grow back unnoticed, or that some other physiological change didn’t trigger the same instincts. With proper monitoring and regular check-ups, the man could be allowed to live as near as he wanted to a school and could even return to his former profession as a teacher.

In other words, the man would still be punished, but he’d just be punished better—in a way that would more closely fit the crime and his personality. Society would just as safe, and his treatment would be fairer. As much of Gazzaniga’s book makes clear by describing the wide-ranging impact of recent discoveries, the amazing thing about neuroscience is how profoundly our growing understanding of the brain will improve justice. We’ll have better ideas about which criminals are incorrigible, which ones need treatment, and which ones should face the same penalties they’ve always faced. Overzealous lawyers and corrupt neuroscientists may sometimes persuade a jury that a prostate tumor can turn someone into a murderer. But overall, neuroscience seems a likely boon to criminal justice, not something to shun—as one of the leading lights in the field oddly seems to want it to be.

Nicholas Thompson