David Eagleman and The Brain on Trial

Imagine for a second that anything you know about the motivations behind criminal activity. For most of us, myself included, our assessment of burglars, murderers, and other deviants is that they have made a choice to act this way (to break the law).

In a remarkable, provocative piece by David Eagleman, he suggests that criminal activity is ingrained in our brains. In no uncertain terms, Eagleman argues that how the human brain is wired ultimately determines how people will act. There is no such thing as free will.

The piece is long (but a must-read in its entirety). I pull a few significant quotes below.

The piece begins about Charles Whitman, a student at the University of Texas at Austin and a former Marine who killed 16 people and wounded 32 others during a shooting rampage on and around the university’s campus on August 1, 1966. The question was why? Eagleman begins to make his argument here, after Whitman’s suicide:

Whitman’s body was taken to the morgue, his skull was put under the bone saw, and the medical examiner lifted the brain from its vault. He discovered that Whitman’s brain harbored a tumor the diameter of a nickel. This tumor, called a glioblastoma, had blossomed from beneath a structure called the thalamus, impinged on the hypothalamus, and compressed a third region called the amygdala. The amygdala is involved in emotional regulation, especially of fear and aggression. By the late 1800s, researchers had discovered that damage to the amygdala caused emotional and social disturbances. In the 1930s, the researchers Heinrich Klüver and Paul Bucy demonstrated that damage to the amygdala in monkeys led to a constellation of symptoms, including lack of fear, blunting of emotion, and overreaction.

Perhaps the paragraph that tells the whole story of the piece:

When your biology changes, so can your decision-making and your desires. The drives you take for granted (“I’m a heterosexual/homosexual,” “I’m attracted to children/adults,” “I’m aggressive/not aggressive,” and so on) depend on the intricate details of your neural machinery. Although acting on such drives is popularly thought to be a free choice, the most cursory examination of the evidence demonstrates the limits of that assumption.

It is fascinating to learn how changing brain chemistry affects our moods, emotions, and behaviors. A classic example:

Changes in the balance of brain chemistry, even small ones, can also cause large and unexpected changes in behavior. Victims of Parkinson’s disease offer an example. In 2001, families and caretakers of Parkinson’s patients began to notice something strange. When patients were given a drug called pramipexole, some of them turned into gamblers. And not just casual gamblers, but pathological gamblers. These were people who had never gambled much before, and now they were flying off to Vegas. One 68-year-old man amassed losses of more than $200,000 in six months at a series of casinos.

Through the mini stories that Eagleman provides in his piece, he explains the lesson: there is no such thing as free will. Human behavior cannot be separated from our brain chemistry:

The lesson from all these stories is the same: human behavior cannot be separated from human biology. If we like to believe that people make free choices about their behavior (as in, “I don’t gamble, because I’m strong-willed”), cases like Alex the pedophile, the frontotemporal shoplifters, and the gambling Parkinson’s patients may encourage us to examine our views more carefully. Perhaps not everyone is equally “free” to make socially appropriate choices.

Now, it’s a little hard to digest that paragraph above. Cleverly, Eagleman begins to question you, the reader, on how you feel about this hypothesis:

Does the discovery of Charles Whitman’s brain tumor modify your feelings about the senseless murders he committed? Does it affect the sentence you would find appropriate for him, had he survived that day? Does the tumor change the degree to which you consider the killings “his fault”? Couldn’t you just as easily be unlucky enough to develop a tumor and lose control of your behavior?

On the other hand, wouldn’t it be dangerous to conclude that people with a tumor are free of guilt, and that they should be let off the hook for their crimes?

As our understanding of the human brain improves, juries are increasingly challenged with these sorts of questions. When a criminal stands in front of the judge’s bench today, the legal system wants to know whether he is blameworthy. Was it his fault, or his biology’s fault?

At this point, Eagleman counters and perhaps worries that he is going to lose readers. Your ideas are crazy, you might think. But please read on, as Eagleman suggests:

If I seem to be heading in an uncomfortable direction—toward letting criminals off the hook—please read on, because I’m going to show the logic of a new argument, piece by piece. The upshot is that we can build a legal system more deeply informed by science, in which we will continue to take criminals off the streets, but we will customize sentencing, leverage new opportunities for rehabilitation, and structure better incentives for good behavior. 

Some overwhelming statistics about criminal behavior:

Who you even have the possibility to be starts at conception. If you think genes don’t affect how people behave, consider this fact: if you are a carrier of a particular set of genes, the probability that you will commit a violent crime is four times as high as it would be if you lacked those genes. You’re three times as likely to commit robbery, five times as likely to commit aggravated assault, eight times as likely to be arrested for murder, and 13 times as likely to be arrested for a sexual offense. The overwhelming majority of prisoners carry these genes; 98.1 percent of death-row inmates do. These statistics alone indicate that we cannot presume that everyone is coming to the table equally equipped in terms of drives and behaviors.

But what about the environmental effects? Surely someone growing up on the mean streets of Detroit would become more predisposed to crime than someone growing up in the quiet suburbs of Wichita, Kansas.

When it comes to nature and nurture, the important point is that we choose neither one. We are each constructed from a genetic blueprint, and then born into a world of circumstances that we cannot control in our most-formative years. The complex interactions of genes and environment mean that all citizens—equal before the law—possess different perspectives, dissimilar personalities, and varied capacities for decision-making. The unique patterns of neurobiology inside each of our heads cannot qualify as choices; these are the cards we’re dealt.

Eagleman further espouses on free will, and explains that it doesn’t exist with a striking example of Tourette’s syndrome:

The legal system rests on the assumption that we are “practical reasoners,” a term of art that presumes, at bottom, the existence of free will. The idea is that we use conscious deliberation when deciding how to act—that is, in the absence of external duress, we make free decisions. This concept of the practical reasoner is intuitive but problematic.

The existence of free will in human behavior is the subject of an ancient debate. Arguments in support of free will are typically based on direct subjective experience (“I feel like I made the decision to lift my finger just now”). But evaluating free will requires some nuance beyond our immediate intuitions.

Consider a decision to move or speak. It feels as though free will leads you to stick out your tongue, or scrunch up your face, or call someone a name. But free will is not required to play any role in these acts. People with Tourette’s syndrome, for instance, suffer from involuntary movements and vocalizations. A typical Touretter may stick out his tongue, scrunch up his face, or call someone a name—all without choosing to do so.

So what’s the purpose of this essay? What can we conclude? Comparatively speaking, we know so little of our brains, that the field of neuroscience can be said to be in its infancy.

Today, neuroimaging [editor’s note: I studied medical imaging both in undergrad at Georgia Tech and at the Brain Imaging Center at California Institute of Technology; I am familiar with the subject matter and for what it’s worth, agree with Eagleman’s assessment] is a crude technology, unable to explain the details of individual behavior. We can detect only large-scale problems, but within the coming decades, we will be able to detect patterns at unimaginably small levels of the microcircuitry that correlate with behavioral problems. Neuroscience will be better able to say why people are predisposed to act the way they do. As we become more skilled at specifying how behavior results from the microscopic details of the brain, more defense lawyers will point to biological mitigators of guilt, and more juries will place defendants on the not-blameworthy side of the line.

Further conclusions from Eagleman. The wrong question to ask: how can we assign a blameworthiness scale in our legal system? Eagleman explain:

Blameworthiness should be removed from the legal argot. It is a backward-looking concept that demands the impossible task of untangling the hopelessly complex web of genetics and environment that constructs the trajectory of a human life.

Instead of debating culpability, we should focus on what to do, moving forward, with an accused lawbreaker. I suggest that the legal system has to become forward-looking, primarily because it can no longer hope to do otherwise. As science complicates the question of culpability, our legal and social policy will need to shift toward a different set of questions: How is a person likely to behave in the future? Are criminal actions likely to be repeated? Can this person be helped toward pro-social behavior? How can incentives be realistically structured to deter crime?

Speaking of wrong questions to ask, Eagleman brilliantly defends here:

The important change will be in the way we respond to the vast range of criminal acts. Biological explanation will not exculpate criminals; we will still remove from the streets lawbreakers who prove overaggressive, underempathetic, and poor at controlling their impulses. Consider, for example, that the majority of known serial killers were abused as children. Does this make them less blameworthy? Who cares? It’s the wrong question. The knowledge that they were abused encourages us to support social programs to prevent child abuse, but it does nothing to change the way we deal with the particular serial murderer standing in front of the bench. We still need to keep him off the streets, irrespective of his past misfortunes. The child abuse cannot serve as an excuse to let him go; the judge must keep society safe.

And then we come to the meat of the essay, where Eagleman gives us an idea of a forward-looking legal system:

Beyond customized sentencing, a forward-thinking legal system informed by scientific insights into the brain will enable us to stop treating prison as a one-size-fits-all solution. To be clear, I’m not opposed to incarceration, and its purpose is not limited to the removal of dangerous people from the streets. The prospect of incarceration deters many crimes, and time actually spent in prison can steer some people away from further criminal acts upon their release. But that works only for those whose brains function normally. The problem is that prisons have become our de facto mental-health-care institutions—and inflicting punishment on the mentally ill usually has little influence on their future behavior. An encouraging trend is the establishment of mental-health courts around the nation: through such courts, people with mental illnesses can be helped while confined in a tailored environment. Cities such as Richmond, Virginia, are moving in this direction, for reasons of justice as well as cost-effectiveness. Sheriff C. T. Woody, who estimates that nearly 20 percent of Richmond’s prisoners are mentally ill, told CBS News, “The jail isn’t a place for them. They should be in a mental-health facility.” Similarly, many jurisdictions are opening drug courts and developing alternative sentences; they have realized that prisons are not as useful for solving addictions as are meaningful drug-rehabilitation programs.

A forward-thinking legal system will also parlay biological understanding into customized rehabilitation, viewing criminal behavior the way we understand other medical conditions such as epilepsy, schizophrenia, and depression—conditions that now allow the seeking and giving of help. These and other brain disorders find themselves on the not-blameworthy side of the fault line, where they are now recognized as biological, not demonic, issues.

But Eagleman closes spectacularly:

As brain science improves, we will better understand that people exist along continua of capabilities, rather than in simplistic categories. And we will be better able to tailor sentencing and rehabilitation for the individual, rather than maintain the pretense that all brains respond identically to complex challenges and that all people therefore deserve the same punishments. Some people wonder whether it’s unfair to take a scientific approach to sentencing—after all, where’s the humanity in that? But what’s the alternative? As it stands now, ugly people receive longer sentences than attractive people; psychiatrists have no capacity to guess which sex offenders will reoffend; and our prisons are overcrowded with drug addicts and the mentally ill, both of whom could be better helped by rehabilitation. So is current sentencing really superior to a scientifically informed approach?

Neuroscience is beginning to touch on questions that were once only in the domain of philosophers and psychologists, questions about how people make decisions and the degree to which those decisions are truly “free.” These are not idle questions. Ultimately, they will shape the future of legal theory and create a more biologically informed jurisprudence.


I’ve highlighted the major sections of the essay, but of course, I encourage you to read the whole thing. It will change your perspective on how you view and think about criminality and our legal system. If for some chance it did not change your course of thinking, why not? Shout out in the comments.

14 thoughts on “David Eagleman and The Brain on Trial

  1. A lot to digest here, but I can’t help thinking about a quote by the gravely ill Christopher Hitchens: “…I don’t have a body. I am a body.” Thanks for this article.

  2. We have no self-control, then? Really?

    If you put a cookie in front of me, sometimes I will eat it. Sometimes, not. Can you tell which choice I will make?

    If I sit at a restaurant perusing the menu and make a decision, then change my mind at my wife’s suggestion, does that mean that I didn’t make a choice after all?

    If a smoker decides to get clean and resists the urge to light up a cigarette, even when his body is telling him to, even when he craves it, is he exercising free will?

    • >”We have no self-control, then? Really?”

      At no point is that stated, or even suggested–certainly nowhere in the full article. I’d suggest that perhaps you’re missing the point.

      But even in asking what I would submit is the “wrong” question, you do raise an interesting one: define “self” control. Which “self” do you mean? 🙂 The one you subjectively perceive as the one who wills things? E.g., “I’m raising my finger because I just chose to do so”?)

      (And what do you do then, for instance, with the objective fact of neurological backdating and temporal juggling done by perception to square what we think we did with what we think we did–there are many instances in the literature–and other recent revelations that undermine the solidity of that folk-wisdom, intuitive “self”?)

  3. You can’t, logically, argue that we have no capacity for choice AND AT THE SAME TIME ask people to change. I mean, if there’s no choice of any degree, then changing the legal system is a logical impossibility, right?

  4. We are our minds, but our minds and our bodies are obviously closely linked. If we are the sum of our genes and our past, then our actions can be explained through these avenues. This does not excuse our behaviour however.

    If a person kills or maims another person, then claimed that their past or biology made them do it, this is equivalent to admitting that they, as a biological (or causal) entity causes this action. It is right to look to fix or prevent such biological causes if possible, but they fail as excuses. They are but reasons.

    Fixing the person is one thing, but a murder causes damage to a comuity. Revenge through punishment sometimes seems like it will help: this is a false promise however. Revenge is a less effective cure for the victim than forgiveness, and this article seems to support that.

    The term “free will” is here used to apply to a freedom to have chosen ones own beginning. Though it might seem sensible to say that one did not chose ones birth, parents, life therefore one is not free, it makes the mistake of making freedom impossible for everyone, forever. For who could ever choose any of these things for themself?

    Therefore the essay is right, but for the wrong reason. We are as free as we need to be, but hate burns like a hot coal and so should be dropped to avoid future pain.

  5. […] David Eagleman and The Brain on Trial « Books I Read Imagine for a second that anything you know about the motivations behind criminal activity. For most of us, myself included, our assessment of burglars, murderers, and other deviants is that they have made a choice to act this way (to break the law). […]

  6. Casey Anthony was acquitted of murder because her defense argued she was abused by her family and learned to become a pathological liar, so she was found guilty of lying instead. The world who watched this televised drama unfold is outraged. Now we learn from her former fiance in post trial interviews, that Casey had been constantly berated by her mother for not doing anything to support herself and her child. In retrospect, it appears Casey’s motivation for the alleged murder of her child may have been her perceived economics straits. With the trial behind her, Casey is now free to gain a lot of money from book deals and she’s already talking of having another child. Alls well that ends well? This is leaving a very bad taste in the majority’s mind. I feel like the “brain model” of criminal justice is still missing a few pieces. Without question, social economic circumstances play a major role in criminal behavior, but one of the missing pieces may be self-concept. I think our society, based on capitalism and free enterprise, the “bella vita” such as it is, needs to pull back and assess what is the “ultimate good”? Basing criminal justice reform on hard sciences like brain science might just backfire if not tempered with the “intangible” … just food thought.

  7. Be careful how much credit you give Eagleman in this essay. He uses three highly controversial and somewhat dubious mental events to make his case. Whitman had a tumor, no doubt about that… but there is no indication that the tumor did anything but amplify what was already inside him. If the tumor activated his fight/flight area of the brain, then why wasn’t he fighting or flighting while he calmly shopped for his killing supplies? Tourette’s is misrepresented by Eaglemen – behavioral modification does work & most people “grow out” of Tourrette’s. Does a person “grow out” of diabetes? Cystic Fibrosis? And the Parkinson’s case of gambling? How many took the drugs but didn’t gamble away their life savings?

    I would encourage anyone to show us a “science” that A) builds its case on less than 1% of the subjects population (Tourettes), B) Holds a phenomenon to be true for the whole that only manifests in les the half the population (Parkinson’s drug), and C) uses a single violent case (Charles Whitman) to illustrate a universal truth, knowing full well that many shooters do not have tumors and many people with the exact same tumor do not become killers.

    This is BAD SCIENCE.

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