by Dan Ariely
Unconscious acts are not limited to unintended shouts or wayward hands; they can be surprisingly sophisticated. Consider Kenneth Parks, a twenty-three-year-old Canadian with a wife, a five-month-old daughter, and a close relationship with his in-laws (his mother-in-law described him as a “gentle giant”). Suffering from financial difficulties, marital problems, and a gambling addiction, he made plans to go see his in-laws to talk about his troubles.
In the wee hours of May 23, 1987, Kenneth arose from the couch on which he had fallen asleep, but he did not awaken. Sleepwalking, he climbed into his car and drove the fourteen miles to his in-laws’ home. He broke in, stabbed his mother-in-law to death, and assaulted his father-in-law, who survived. Afterward, he drove himself to the police station. Once there, he said, “I think I have killed some people . . . . My hands,” realizing for the first time that his own hands were severely cut.
Over the next year, Kenneth’s testimony was remarkably consistent, even in the face of attempts to lead him astray: he remembered nothing of the incident. Moreover, while all parties agreed that Kenneth had undoubtedly committed the murder, they also agreed that he had no motive. His defense attorneys argued that this was a case of killing while sleepwalking, known as homicidal somnambulism.
Although critics cried “Faker!” sleepwalking is a verifiable phenomenon. On May 25, 1988, after lengthy consideration of electrical recordings from Kenneth’s brain, the jury concluded that his actions had indeed been involuntary and declared him not guilty.
As with Tourette’s sufferers, split-brain patients, and those with choreic movements, Kenneth’s case illustrates that high-level behaviors can take place in the absence of free will. Like your heartbeat, breathing, blinking, and swallowing, even your mental machinery can run on autopilot. The crux of the question is whether all of your actions are fundamentally on autopilot or whether some little bit of you is “free” to choose, independent of the rules of biology.
This has always been the sticking point for philosophers and scientists alike. After all, there is no spot in the brain that is not densely interconnected with—and driven by—other brain parts. And that suggests that no part is independent and therefore “free.” In modern science, it is difficult to find the gap into which to slip free will—the uncaused causer—because there seems to be no part of the machinery that does not follow in a causal relationship from the other parts.
Free will may exist (it may simply be beyond our current science), but one thing seems clear: if free will does exist, it has little room in which to operate. It can at best be a small factor riding on top of vast neural networks shaped by genes and environment. In fact, free will may end up being so small that we eventually think about bad decision making in the same way we think about any physical process, such as diabetes or lung disease.
The study of brains and behaviors is in the midst of a conceptual shift. Historically, clinicians and lawyers have agreed on an intuitive distinction between neurological disorders (“brain problems”) and psychiatric disorders (“mind problems”). As recently as a century ago, a common approach was to get psychiatric patients to “toughen up,” through deprivation, pleading, or torture. Not surprisingly, this approach was medically fruitless. After all, while psychiatric disorders tend to be the product of more subtle forms of brain pathology, they, too, are based in the biological details of the brain.
What accounts for the shift from blame to biology? Perhaps the largest driving force is the effectiveness of pharmaceutical treatments. No amount of threatening will chase away depression, but a little pill called fluoxetine often does the trick. Schizophrenic symptoms cannot be overcome by exorcism, but they can be controlled by risperidone. Mania responds not to talk or to ostracism but to lithium. These successes, most of them introduced in the past sixty years, have underscored the idea that calling some disorders “brain problems” while consigning others to the ineffable realm of “the psychic” does not make sense. Instead, we have begun to approach mental problems in the same way we might approach a broken leg. The neuroscientist Robert Sapolsky invites us to contemplate this conceptual shift with a series of questions:
Is a loved one, sunk in a depression so severe that she cannot function, a case of a disease whose biochemical basis is as “real” as is the biochemistry of, say, diabetes, or is she merely indulging herself? Is a child doing poorly at school because he is unmotivated and slow, or because there is a neurobiologically based learning disability? Is a friend, edging towards a serious problem with substance abuse, displaying a simple lack of discipline, or suffering from problems with the neurochemistry of reward?
Acts cannot be understood separately from the biology of the actors—and this recognition has legal implications. Tom Bingham, Britain’s former senior law lord, once put it this way:
In the past, the law has tended to base its approach . . . on a series of rather crude working assumptions: adults of competent mental capacity are free to choose whether they will act in one way or another; they are presumed to act rationally, and in what they conceive to be their own best interests; they are credited with such foresight of the consequences of their actions as reasonable people in their position could ordinarily be expected to have; they are generally taken to mean what they say.
Whatever the merits or demerits of working assumptions such as these in the ordinary range of cases, it is evident that they do not provide a uniformly accurate guide to human behaviour.
The more we discover about the circuitry of the brain, the more we tip away from accusations of indulgence, lack of motivation, and poor discipline—and toward the details of biology. The shift from blame to science reflects our modern understanding that our perceptions and behaviors are steered by deeply embedded neural programs.
Imagine a spectrum of culpability. On one end, we find people like Alex the pedophile or a patient with frontotemporal dementia who exposes himself in public. In the eyes of the judge and jury, these are people who suffered brain damage at the hands of fate and did not choose their neural situation. On the other end of the spectrum—the blameworthy side of the “fault” line—we find the common criminal, whose brain receives little study and about whom our current technology might be able to say little anyway. The overwhelming majority of lawbreakers are on this side of the line, because they don’t have any obvious, measurable biological problems. They are simply thought of as freely choosing actors.
Such a spectrum captures the common intuition that juries hold regarding blameworthiness. But there is a deep problem with this intuition. Technology will continue to improve, and as we grow better at measuring problems in the brain, the fault line will drift into the territory of people we currently hold fully accountable for their crimes. Problems that are now opaque will open up to examination by new techniques, and we may someday find that many types of bad behavior have a basic biological explanation—as has happened with schizophrenia, epilepsy, depression, and mania.
Today, neuroimaging is a crude technology, unable to explain the details of individual behavior. We can detect only large-scale problems, but in 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.
This puts us in a strange situation. After all, a just legal system cannot define culpability simply by the limitations of current technology. Expert medical testimony generally reflects only whether we yet have names and measurements for a problem, not whether a problem exists. A legal system that declares a person culpable at the beginning of a decade and not culpable at the end is one in which culpability carries no clear meaning.
The crux of the problem is that it no longer
makes sense to ask, “To what extent was it his biology, and to what extent was it him?” because we now understand that there is no meaningful distinction between a person’s biology and his decision making. They are inseparable.
While our current style of punishment rests on a bedrock of personal volition and blame, our modern understanding of the brain suggests a different approach. 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 prosocial behavior? How can incentives be realistically structured to deter crime?
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.
Those who break social contracts need to be confined, but in this framework, the future is more important than the past. Deeper biological insight into behavior will foster a better understanding of recidivism—and this offers a basis for empirically based sentencing. Some people will need to be taken off the streets for a longer time (even a lifetime), because their likelihood of reoffense is high; others, because of differences in neural constitution, are less likely to recidivate and so can be released sooner.
The law is already forward-looking in some respects: consider the leniency afforded a crime of passion versus a premeditated murder. Those who commit the former are less likely to recidivate than those who commit the latter, and their sentences sensibly reflect that. Likewise, American law draws a bright line between criminal acts committed by minors and those by adults, punishing the latter more harshly. This approach may be crude, but the intuition behind it is sound: adolescents command lesser skills in decision making and impulse control than do adults; a teenager’s brain is simply not like an adult’s brain. Lighter sentences are appropriate for those whose impulse control is likely to improve naturally as adolescence gives way to adulthood.
Taking a more scientific approach to sentencing, case by case, could move us beyond these limited examples. For instance, important changes are happening in the sentencing of sex offenders. In the past, researchers asked psychiatrists and parole-board members how likely specific sex offenders were to relapse when let out of prison. Both groups had experience with sex offenders, so predicting who would go straight and who would come back seemed simple. But surprisingly, the expert guesses showed almost no correlation with the actual outcomes. The psychiatrists and parole-board members had only slightly better predictive accuracy than coin-flippers. This astounded the legal community.
So researchers tried a more actuarial approach. They set about recording dozens of characteristics of some 23,000 released sex offenders: whether the offender had unstable employment, had been sexually abused as a child, was addicted to drugs, showed remorse, had deviant sexual interests, and so on. Researchers then tracked the offenders for an average of five years after release to see who wound up back in prison. At the end of the study, they computed which factors best explained the reoffense rates, and from these and later data they were able to build actuarial tables to be used in sentencing.
Which factors mattered? Take, for instance, low remorse, denial of the crime, and sexual abuse as a child. You might guess that these factors would correlate with sex offenders’ recidivism. But you would be wrong: those factors offer no predictive power. How about antisocial personality disorder and failure to complete treatment? These offer somewhat more predictive power. But among the strongest predictors of recidivism are prior sexual offenses and sexual interest in children. When you compare the predictive power of the actuarial approach with that of the parole boards and psychiatrists, there is no contest: numbers beat intuition. In courtrooms across the nation, these actuarial tests are now used in presentencing to modulate the length of prison terms.
We will never know with certainty what someone will do upon release from prison, because real life is complicated. But greater predictive power is hidden in the numbers than people generally expect. Statistically based sentencing is imperfect, but it nonetheless allows evidence to trump folk intuition, and it offers customization in place of the blunt guidelines that the legal system typically employs. The current actuarial approaches do not require a deep understanding of genes or brain chemistry, but as we introduce more science into these measures—for example, with neuroimaging studies—the predictive power will only improve. (To make such a system immune to government abuse, the data and equations that compose the sentencing guidelines must be transparent and available online for anyone to verify.)
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.
Many people recognize the long-term cost-effectiveness of rehabilitating offenders instead of packing them into overcrowded prisons. The challenge has been the dearth of new ideas about how to rehabilitate them. A better understanding of the brain offers new ideas. For example, poor impulse control is characteristic of many prisoners. These people generally can express the difference between right and wrong actions, and they understand the disadvantages of punishment—but they are handicapped by poor control of their impulses. Whether as a result of anger or temptation, their actions override reasoned consideration of the future.
If it seems difficult to
empathize with people who have poor impulse control, just think of all the things you succumb to against your better judgment. Alcohol? Chocolate cake? Television? It’s not that we don’t know what’s best for us, it’s simply that the frontal-lobe circuits representing long-term considerations can’t always win against short-term desire when temptation is in front of us.
With this understanding in mind, we can modify the justice system in several ways. One approach, advocated by Mark A. R. Kleiman, a professor of public policy at the University of California, Los Angeles, is to ramp up the certainty and swiftness of punishment—for instance, by requiring drug offenders to undergo twice-weekly drug testing, with automatic, immediate consequences for failure—thereby not relying on distant abstraction alone. Similarly, economists have suggested that the drop in crime since the early 1990s has been due, in part, to the increased presence of police on the streets: their visibility shores up support for the parts of the brain that weigh long-term consequences.
We may be on the cusp of finding new rehabilitative strategies as well, affording people better control of their behavior even in the absence of external authority. To help a citizen reintegrate into society, the ethical goal is to change him as little as possible while bringing his behavior into line with society’s needs. My colleagues and I are proposing a new approach, one that grows from the understanding that the brain operates like a team of rivals, with different neural populations competing to control the single output channel of behavior. Because it’s a competition, the outcome can be tipped. I call the approach “the prefrontal workout.”