'You Can't See Why on an fMRI'

What science can, and can't, tell us about the insanity defense


On the morning of June 20, 2001, Officer David Knapp responded to a 911 dispatch call in the Houston suburbs. A thin woman with long dark hair, fully dressed but inexplicably wet, answered the door. She was breathing heavily. The cop's first glance into the house revealed no obvious crisis.
Knapp asked the woman why she had called the police. Her reply was the opening line in a long public drama that continued until the summer of 2006, when the woman, Andrea Yates, was acquitted by reason of insanity for the deed she announced to Knapp: "I just killed my kids."

The corpses of four of Yates' five children—ages 5, 3, 2, and 6 months—were in the master bedroom, scrupulously covered in burgundy cotton sheets. The corpse of her oldest child, 7-year-old Noah, was still in the bathroom, floating face down in the bathtub. The tub was filled almost to the top with water, plus the vomit and excrement that had left the children's bodies as their mother grabbed them, choked them, beat them, and shoved their heads under the water until their lungs burst and they died.

Homicide investigator Bob King, summoned to the murder scene a couple hours later, summed up this freakishly horrible case: "Something like this, you just got to wonder." So did the courts, and so did we all. After five years and two trials with contradictory verdicts, we're still wondering.
Within 24 hours of Knapp's visit, Andrea Yates was America's most infamous mother. Her ongoing saga was both soap opera and legal drama, with a fascinating backstory starring a fanatical traveling preacher, a hapless husband, a hopeless wife, heedless doctors making possibly fatal errors, and bizarre living conditions outside the ken of the middle-class viewers following along on Court TV.

Yates became a tragic figure to some, driven by unmanageable forces of faith, family, and madness. Her acts were so difficult to understand that insanity seemed the only sane explanation. Yet while virtually everyone was horrified by her crimes, some women could also examine their hearts and circumstances, and wonder. As Newsweek columnist Anna Quindlen wrote right after the murders: "Every mother I've asked about the Yates case has the same reaction. She's appalled; she's aghast. And then she gets this look. And the look says at some forbidden level she understands."

The public reaction to the Yates case combined an insistence on blaming a mentally ill Other with a clandestine understanding that human passions cover a wider range than we like to admit. Such mixed feelings underlie the medical concept of mental illness and the legal concept of insanity, both of which allow us to categorize and explain that which we cannot, or do not want to, understand.

By testifying in trials as expert witnesses, mental health professionals help us reclassify complicated moral and legal questions as seemingly clear-cut scientific matters. An endless stream of news stories about the latest advances in brain scans and the chemical conquest of personality enhances the experts' credibility and feeds into a belief that we have come to a sophisticated understanding of the intersection between mind, brain, and behavior.

But a close look at Andrea Yates' legal saga, along with a less-famous Supreme Court decision about the insanity defense that was handed down shortly before she was acquitted, casts doubt on the scientific validity and legal relevance of psychiatric testimony. Despite all those popular accounts of high-tech tools for understanding the mind, the real role of psychiatry in the courts is far from objective and unimpeachable. It amounts to adding yet another debatable perspective to an already fuzzy scene.

The Insanity Defense: Rare and Well Done?
When legal and psychiatric experts are asked about the insanity defense, they are apt to repeat wearily that it comes up in barely more than 1 percent of criminal cases and succeeds in only a quarter of those. They will also note that a verdict of "not guilty by reason of insanity" doesn't mean the criminal goes traipsing off scot-free, laughing maniacally to himself. In almost every case the "acquitted" defendant gets locked up, not in a jail but in a mental health facility. He'll stay there until some authority figure or body (depending on the state, it might be a judge or a board of psychiatric professionals) decides he is no longer a danger to the public. Defendants often spend more time locked up after "getting off" via the insanity defense than they would have if they'd been found guilty.

Despite the rarity of the defense, we talk about it a lot. In part that's because it makes for particularly colorful moral and legal drama, since it generally arises in cases where the crime seems to be beyond most normal people's ken. But it's also because the defense raises deep and eternally controversial questions about compulsion and free will.

Yates dragged the insanity defense back into the headlines when she returned to court last summer for a retrial. Her initial 2002 conviction for murdering three of her children—the state held off on trying her for the other two—was overturned because Park Dietz, a psychiatric expert witness who testified for the prosecution, said something on the stand that wasn't true. He claimed that an episode of Law & Order (a show for which he consulted, and of which Yates was a fan) featured a woman who drowned her kids and got off with an insanity plea. The implication was that Yates had gotten the idea for her defense from the show. But no such episode existed.

In January 2005 a state appeals court, concluding that Dietz's error might have affected the jury's decision, overturned Yates' conviction. In her second trial, with a similar set of psychiatric professionals making similar arguments for and against her, she was acquitted last July by reason of insanity. Then Yates, officially guilty of no crime, was locked up in the maximum-security North Texas State Hospital at Vernon. (In January she was moved to Kerrville State Hospital.)

Yates' legal team sold a narrative about a woman suffering from a physical problem with her brain. That problem, they argued, was more responsible for her crimes than she was; it removed her from the normal human realms of choice and responsibility. We know about this alleged physical problem with her brain not because the experts actually analyzed that organ, but because of the things she has done and said, and the ways certain drugs seemed to affect her emotions and behavior.

Andrea Yates had a history, going back to 1999, of bizarre and disturbing behavior, from extended fasts to attempted suicides with pills and knives. Her husband, NASA engineer Rusty Yates, had taken her to a series of psychiatric institutes. A string of doctors had diagnosed her with postpartum depression and schizoaffective disorder, giving her a variety of antipsychotics and antidepressants. Some of the drugs seemed, at least for a while, to relieve the more obvious symptoms of mental disturbance, such as incessantly pumping her feet up and down and an almost catatonic lack of communication.

Yates' actions and words on the day of the murder certainly don't seem, from a common-sense perspective, to indicate that she was outside the realm of choice and morality. She waited for a small gap in her day after Rusty went to work and before her mother-in-law, who helped her with the kids, showed up; she committed the murders methodically; she summoned both her husband and the police to her home promptly afterward.

None of the mental illnesses with which Yates was alternately diagnosed seem to be a sufficient explanation for her actions. Very few people diagnosed with postpartum psychosis, schizophrenia, or major depression kill anyone, much less their own children. Something other than a disease seems necessary to explain her actions adequately. In the opinions of many expert witnesses, a sizable portion of the lay public, and the first jury, the most sensible candidate for that something was Andrea Yates' choice, for whatever reason, to murder her five children. If so, many reasoned, she deserved the same treatment from the legal system as anyone else who made that choice, for whatever reason.

Many others disagreed, including the second jury. Such people thought that the diagnosis of mental illness was sufficient proof that Yates was beyond the realm of moral choice—that she had the inability to understand right and wrong required by Texas' insanity defense. To make this case, they referred frequently to recent advances in neuroscience.

As long ago as 1985, serious, scientific books about the insanity defense were asserting that, as the criminologist C.R. Jeffery wrote in the collection Attacks on the Insanity Defense, "it is now possible to prove the presence or absence of schizophrenia or sociopathy through neurological tests of the brain." Today we are told in venues high and low that advanced tools of brain study are highly relevant to our understanding of human behavior, in or out of court. An article by Deborah Denno in the Duke Journal of Gender Law and Policy complained that juries in general lack understanding of the "physiological underpinnings of…psychoses." In January Time declared that "neuroscientists can almost read people's thoughts." Last year The New York Times' Benedict Carey wrote—exaggerating for effect, but with no doubt that he was exaggerating a widespread popular understanding—that "At this rate, it seems that neuroscientists will soon pinpoint the regions in the brain where mediocre poetry is generated, where high school grudges are lodged, where sarcasm blooms like a red rose." A 2005 op-ed in the Hackensack, New Jersey, Record tried to explain what was going on with Yates by declaring, "Brain scans apparently have shown differences in a postpartum brain from other brains."

Having written about the case as it unfolded, I know from my own experience that to suggest Yates be considered morally and legally responsible for her actions invites widespread condemnation. Whether in emails from far and wide or in heated bar arguments, I've been derided as a Neanderthal who is ignorant of modern psychiatry, neuroscience, and the true nature of mental illness.

It's interesting, then, that none of the celebrated objective brain-analyzing technologies—not functional magnetic resonance imaging (fMRI), not positron emission tomography (PET), not computed axial tomography (CAT)—had any bearing on the Yates case as it was presented in court, or on insanity defense cases in general. Neither did any of those techniques play a role in her dealings with medical professionals.

The diagnosis and judgment of Yates were based on old-fashioned methods: talking to her and contemplating her statements and actions. For the most part, what scientific expert witnesses in such cases do is to interpret actions, not analyze objective facts. Neuroscientific advances have done nothing to change that, marking interesting and perhaps permanent gaps between psychiatry and the law.

Critics on the Stand
The expert-witness debates in the Yates trials thus seemed more like literary criticism than medical science. The dueling explanations of what was going on in Yates' head that grim morning were not based on looking into that head with tools that only a professional would be competent to use and interpret for a jury. They were based on observations and interpretations of the sort that every reader posting on CourtTV.com was doing, and with similar conclusions.

In his testimony in Yates' first trial, Park Dietz argued that, given her intense religiosity, Yates' claim that the command to drown her children came from Satan proves she knew it was an evil impulse. When Dietz suggested to Yates during their interview session, "You saw it as a sin that you were going to commit," she answered simply, "Yes." For Dietz, the facts that Yates called the cops right after killing her kids and said to one of them that she was a bad mother who deserved to be punished showed she knew it was wrong to drown her children.

Testifying for the defense, Phillip Resnick, director of the forensic division at Case Western Reserve University, pointed out that Yates also said at a different time that she was sure drowning her children now—before, say, young Paul could become the mute homosexual prostitute she obsessively fantasized he would become—would guarantee them entrance to heaven. According to Resnick, this showed she meant to help, not harm, her children and thus did not know the legal difference between right and wrong, as required to convict her. In fact, he argued, Yates believed what she was doing was right, even if she understood society would punish her for it.

By Resnick's account, Yates recognized that her act was against the laws of man but believed it was in accord with the law of God because it would ensure her children an eternity in paradise. She had told Resnick she was tormented by the fact that her children seemed to be growing into kids who were "not righteous," who were distant from God. Killing her children would serve their long-term well-being by ensuring that they "did not stumble." As Resnick said on the stand, "Mrs. Yates had a choice to make: to allow her children to end up burning in hell for eternity or to take their lives on earth."

Michael Welner, an expert witness for the prosecution in the second trial, offered an alternative interpretation. "It is my professional opinion, with a reasonable degree of psychiatric certainty," he said in a written report offered to the court, "that the psychotic aspects of Andrea Yates at the time of her crimes included delusional self-reproach of her failure as a parent, and referential thinking amplifying her failures, and her feelings that she needed to be punished. Other symptoms developed when she was buffeted with the enormity of her actions, including hallucinations, irrational identification with Satan, disorganized speech, labile emotions, and bizarre behavior." Welner finally pointed out that "Andrea Yates did not say, 'I saved the children,' or 'I ushered them into the next world,' 'I just sent the children to heaven,' or 'I just saved my children,' she said 'I killed my children'—twice" (emphasis in original).

In the first trial, the jury was convinced by one set of arguments about the motives of the lead character in the drama, and it found Yates guilty. In the second trial, a different jury was convinced by a different version of the narrative, and it found her not guilty by reason of insanity. But neither narrative seems to have anything to do with medical expertise.

As the psychologists Charles Patrick Ewing and Joseph T. McCann revealed in their 2006 book Minds on Trial, psychiatric testimony often consists of making closing arguments for the defense (or prosecution) under the guise of science, rather than applying specific expert knowledge. It may amount to accepting the sincerity of a defendant's claim that he committed his crime for a seemingly insane reason, such as a supernatural command. Or it may mean offering an alternative explanation for the crime that makes it seem as if the defendant doesn't meet the legal definition of insanity. Ewing and McCann ultimately conclude that there are "sometimes serious questions as to whether [professional psychiatric] input has actually helped or hindered the justice system."

A History of Insanity
The belief that certain mental states remove defendants from the realm of legal responsibility goes back to at least 1505. In modern America, a handful of standards have jockeyed for position to define insanity and legal responsibility. The first was the "M'Naghten rule," named after an 1843 British case involving a Scottish woodcutter, Daniel M'Naghten, who tried to kill Prime Minister Robert Peel but fatally shot Peel's secretary instead. M'Naghten, who insisted he was trying to stop Peel from killing him, was acquitted. According to the standard that arose from that case—nowadays still the basis for the insanity defense in nearly half the states in the U.S.—a defendant should not be held legally responsible for his crime if, due to "a defect of reason" caused by a "disease of the mind," he either did not know what he was doing or did not know it was wrong.

From the 1950s through the early '80s, American insanity defense law passed through several stages with dueling standards. Then came the trial of John Hinckley, the would-be murderer of Ronald Reagan, who was found not guilty by reason of insanity in 1984. The ensuing backlash led to the Insanity Defense Reform Act of 1984, which changed the federal standards for the insanity defense. About half the states also adjusted their insanity standards in the wake of Hinckley. For the most part, the federal statute and the state-level reforms eliminated a consideration from a previous standard that the defendant be mentally able to conform his conduct to the law, and declared that the mental illness had to be "severe."

The variations in state standards for the insanity defense led to a 2006 Supreme Court case, Clark v. Arizona, in which a majority of justices seemed to agree that the judicial system doesn't necessarily have to follow the guidance of psychiatric experts. The case involved Eric Clark, a young man from Arizona who claimed to believe, as the Supreme Court put it, "that 'aliens' (some impersonating government agents) were trying to kill him and that bullets were the only way to stop them."

In June 2000, Clark, then 17, shot Jeff Moritz, a police officer who came to question him as he circled a residential street in Flagstaff in his pickup truck, blasting disturbingly loud music. Clark had told some acquaintances a few weeks earlier that he wanted to shoot some cops, which helped cast doubt on his later assertion that he thought he was shooting an alien rather than a police officer. Police found Clark later that day with gunpowder residue on his hands. They found the gun inside a knit cap near the scene of the shooting. In 2003, despite his insanity plea, he was convicted and sentenced to life in prison. (Curiously, Moritz's father is himself a psychologist with experience in evaluating defendants' competency to stand trial.)

Clark's lawyers argued that Arizona's insanity defense standard was so stringent that it violated their client's right to due process. Under this standard, a defendant can be found "guilty except insane" (the phrase preferred in Arizona) if he did not realize his actions were wrong. He is then eligible to be confined in a psychiatric hospital rather than prison. Unlike the M'Naghten rule, the Arizona standard makes no explicit provision for a defendant who, because of a mental defect, did not "know the nature and quality" of his act. Without the other half of the M'Naghten rule, Clark's lawyers insisted, Arizona's insanity defense standard "offends [a] principle of justice so rooted in the traditions and conscience of our people as to be ranked as fundamental."

That's crazy, the Supreme Court said. In the first place, the "not knowing an action is wrong" part of M'Naghten that Arizona preserved really still includes the part about not knowing the "nature and quality" of the act. If you don't know what you did, you obviously don't know it's wrong.
Besides, wrote Justice David Souter in the majority opinion, the history of the insanity defense shows that "no particular formulation [for the insanity defense] has evolved into a baseline for due process." In fact, he said, the Due Process Clause does not even require a state to recognize an insanity defense. Four states—Kansas, Idaho, Utah, and Montana—technically do not, with the latter two having an alternate "guilty but mentally ill" category with little practical effect on the defendant if he's found guilty. (One caustic legal scholar called it as meaningful as a "guilty but herpes" verdict.)

Clark's lawyers also argued that the Arizona court violated their client's right to due process by barring him from using professional testimony regarding mental illness to rebut the presumption of mens rea (that the accused acted knowingly and intentionally). The Supreme Court rejected that argument as well, and its reasoning in doing so undermines the basis for using psychiatric testimony at all. The Court noted that the "controversial character of some categories of mental disease, the potential of mental-disease evidence to mislead, and the danger of according greater certainty to capacity evidence than experts claim for it" give Arizona good cause to limit the areas where psychiatric testimony applies.

"The consequences of professional ferment," the Court said, "is a general caution in treating psychological classifications as predicates for excusing otherwise criminal conduct." In other words, psychiatrists disagree on diagnoses and their legal significance, to an extent that casts doubt on the objectivity of their science and its value for judges or juries. Clark's original trial featured dueling psychiatric witnesses who agreed he was schizophrenic (one of the most wide-ranging and vague psychiatric classifications) but disagreed about what this diagnosis implied regarding his capacity to judge right and wrong.

The Supreme Court recognized that there is often no reason to believe a psychiatrist has any more knowledge on these legal and moral questions than a layman. "Empirical and conceptual problems" with psychiatry, Souter wrote, "add up to a real risk that an expert's judgment in giving capacity evidence will come with an apparent authority that psychologists and psychiatrists do not claim to have."

The case is too recent for us to have any clear notion of what long-term effects it will have on the practical nexus of psychiatry and law. Both the American Psychiatric Association and the American Psychological Association joined in an amicus brief asking the court to decide the case the other way. The Medill News Service reported after the decision that Dr. Paul Appelbaum, chair of the Counsel for Psychiatry and Law for the American Psychiatric Association and a former president of the organization, was bothered that, as the reporter put it, the "decision suggests that psychiatric expert testimony is less reliable than other forms of evidence" and thought that "the opinion seemed to reflect a bias against the field of mental health."

On the legal front, Richard Bonnie, director of the Institute of Law, Psychiatry, and Public Policy at the University of Virginia, tells me that in his judgment when the Court discussed the merits of psychiatric testimony it was merely reaching for an excuse for the result it wanted to achieve—to uphold Arizona's right to have its own policies on insanity and permitted evidence. It's unlikely, he says, to have much effect on future jurisprudence.

Some law journal articles have already judged the court's reasoning in Clark and found it wanting. In a monograph published by the University of Pennsylvania Law School, Stephen Morse (a law professor at Penn) and Morris B. Hoffman (a state district court judge in Colorado) declared that the court's reasoning was confused about the distinctions between the insanity defense and mens rea and thus often dealt with issues the case didn't really raise. Morse and Hoffman also tried to grapple with the meaning of modern neuroscience to the law, ultimately concluding that, from a legal perspective, "even if pure [neurological] mechanism is true…human beings will find it almost impossible not to treat themselves as rational, intentional agents unless there are major changes in the way our brains work. Indeed…there are powerful evolutionary explanations for the causal efficacy of our mental states [that make us think we have free will], states that are the predicates for responsibility. Overcoming what may in fact be neuro-architectural facts of evolution may be only a little less likely than 'overcoming' our opposable thumbs."

Insanity vs. Free Will
As Morse and Hoffman recognized, the insanity defense is far from a simple legal issue. It is tangled with many controversial questions of science and philosophy. What is the relationship between mind and brain? Is there free will, such that any of us, sane or insane, are really responsible for what we do? Some neuroscientists and philosophers say the "free will" that appears to lie behind traditional legal notions of responsibility and blame is nonsense, that belief in it is as outmoded as belief in phlogiston or a flat Earth. Others counter than none of science's interesting discoveries about how our brains work has enabled us to specify how an observable physical or chemical action in the brain equals (or dictates) a thought, an emotion, or an action.

The Harvard linguist and psychologist Steven Pinker, author of How the Mind Works, summarized the optimistic belief in what neuroscience teaches us (or will soon teach us), and why it is controversial, in the January 29 issue of Time. "Few scientists doubt that they will locate consciousness in the activity of the brain," he wrote. "For many nonscientists, this is a terrifying prospect. Not only does it strangle the hope that we might survive the death of our bodies, but it also seems to undermine the notion that we are free agents responsible for our choices."

Steven Faux, chairman of the psychology department at Drake University, wonders how much neuroscience tools have really done for us so far. An fMRI scan, for example, attempts to measure neuronal activity by detecting blood flow in the brain. But as Faux told Scientific American in 2005, "The beautiful graphics fMRI produces imply much more precision than there actually is. It's really a very gross, if not vague, physiological measurement that people are using to try to pin down some very complex behaviors. And in too many studies the authors way overinterpret the data." Critics of fMRIs, such as William Uttal, an emeritus professor of psychology at the University of Michigan, question whether brain function is compartmentalized enough for information about blood flow to tell us much, condemning the process as "the new phrenology." Dr. Jay Giedd, chief of brain imaging in the child psychiatry branch at the National Institute of Mental Health, told The New York Times in 2005: "I have been waiting for my work in the lab to affect my job on the weekend, when I practice as a child psychiatrist. It hasn't happened. In this field, every year you hear, 'Oh, it's more complicated than we thought.' Well, you hear that for 10 years, and you start to see a pattern."

The effects of psychiatric drugs likewise do not indicate that we have developed a clear picture of how brain activity is related to behavior. The Clinical Antipsychotic Trials of Intervention Effectiveness, the results of which were reported last year in The New England Journal of Medicine, found that even newer antipsychotics such as olanzapine (sold under the trade name Zyprexa) and risperidone (Risperdal) are not necessarily safe and effective for most patients. In the 18-month study, nearly three-fourths of the patients refused to keep taking the drugs because they didn't work or had intolerable side effects, including slurred speech, loss of coordination, insomnia, and weight gain.

And when it comes to antidepressants, a 2002 study by the University of Connecticut psychologist Irving Kirsch found that, as Kirsch wrote in a Psychiatric Times summation of his research, "although the response to antidepressants was substantial, the response to inert placebo was almost as great. The mean difference was…not clinically significant.…More than half of the clinical trials sponsored by the pharmaceutical companies failed to find significant drug/placebo difference."

Other studies have shown significant placebo effects for many physical ailments, from pain to high blood pressure, further limning the links between beliefs in the mind and what happens in our bodies. It seems reasonably clear that something arises as an emergent property of our brains' matter in motion that can act on that matter. Chemicals in the brain obviously have a strong influence on the mental realms of choice and intention, as well as on the physical ones of behavior and action. Just ask anyone who has ever been drunk or high.

But metaphysical intangibles such as choice, intention, and judgment also, by universal human experience, affect chemicals in the brain. The conscious mind seems to itself cause activity in the physical organ from which it emerges. Why do sad songs or stories make us feel sad? Chemicals moving hither and yon influence and perhaps in some sense cause the felt emotion of sadness—but what makes them take action when they do? Why does adrenaline create edgy nervousness in a person about to speak before a crowd?

Purpose, intention, and judgment are so built into our felt experience that we cannot eliminate them from our consideration of human action, no matter how hard we try or what our metaphysical presumptions and scientific beliefs might be. As the Supreme Court acknowledged in Clark, the mind-brain perplexity needs much more scientific work before its study can be of dispositive use to the law.

Even if we had certain answers to these big, complicated questions of free will vs. determinism, or understood the precise neurological cause of mental problems, that wouldn't necessarily dictate how the legal system should deal with those diagnosed as mentally ill. Some physical determinists have concluded that neuroscience cannot tell us whether we should hold people legally responsible for their actions.

The Dartmouth neuroscientist Michael Gazzaniga, author of The Ethical Brain and a proponent of a fully deterministic "brain-based philosophy of life," told U.S. News and World Report in 2005 that he has never believed in the insanity defense. "One of the reasons," he said, "is, if you look at schizophrenics, for example, their rate of violent behavior is not above that of the normal population, especially when they're on their medication. So, if that's true, how can you use that as a defense, that they're doing something because they're insane?" Personal responsibility, he explained, "has to do with the fact that people follow rules because they're in a social group, and people with these various kinds of disorders can still follow those rules."

Harvard's Pinker figures that we can simultaneously believe in a fully caused human being and an ethical system that holds people responsible for their actions by imagining ethics as a "game" that it is useful for us to play for social purposes. In How the Mind Works, he writes that "the ethics game treats people as equivalent, sentient, rational, free-willed agents, and its rules are the calculus that assigns moral value to behavior through the behavior's inherent nature or its consequences. Free will is an idealization of human beings that makes the ethics game playable." The results of that game, he concludes, "can be sound and useful even though the world, as seen by science, does not really have uncaused events."

Understanding Why

Juries and judges need to know what happened and why. As the Yates and Clark cases illustrate, psychiatry and neuroscience are not much help in answering those questions, despite the constant promise that a deeper and more expansive understanding of the relationship between brain and mind is just around the corner.

The closest we can come to knowing why Andrea Yates drowned her children or why Eric Clark shot a police officer is that they, or their neurons, chose to do it. Whether that choosing arose from irreducible free will or was merely an illusion, an outcome inevitable since one particle bumped into another during the Big Bang, remains unknown for now, despite anything a psychiatrist or neuroscientist might theorize.

Phillip Resnick, one of the leading witnesses in Andrea Yates' defense, certainly believes in the value of expert psychiatric testimony in court. He testified that delusions caused by postpartum psychosis qualified Yates for the insanity defense under the Texas standard. But while he completely disagrees with those who think Yates was guilty in any normal sense of the word for her killing her children, his reasons have nothing to do with fMRIs or other high-tech windows to the brain.

He drew his conclusions the old-fashioned way, a way that doesn't necessarily require a medical expert: by observing Yates and by talking to her and to people who knew her. He believed, from such evidence, that she was in the grip of psychotic delusions when she killed her kids, delusions that made her think that drowning them was in fact the right thing to do to save their souls.

Resnick's belief convinced the second jury, without any recourse to objective neuroscience and its promises to help us understand exactly what in our brains makes us think, feel, and act as we do. Even in the 21st century, our ability to make those kinds of legal and moral judgments remains largely untouched by purely objective science. To make the judgments about human beings and their behavior that courts need to make, Resnick says, "You need to understand why. And you can't see why on an fMRI."

Senior Editor Brian Doherty is the author of This Is Burning Man (BenBella Books) and Radicals for Capitalism (PublicAffairs).

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