Dazzling brain imaging has helped neuroscience make great advances, but it still can’t fully explain why we make the choices we do. Our values still guide our decisions, for good or for bad.
In May 1924, two young men set out to kidnap and murder a child of an affluent family. Nathan F. Leopold, Jr., aged nineteen, and Richard Loeb, eighteen, had spent months planning and rehearsing what they called ”the perfect crime.” On the day of the killing, they chose a convenient victim: fourteen-year-old Bobby Franks, who was Loeb’s second cousin and the son of a local millionaire.
As Franks walked home from school on a late afternoon in Chicago’s leafy Hyde Park neighborhood, the two pulled up alongside him in a rented roadster and invited him to hop in. After a few minutes of small talk about a tennis racket, they bludgeoned the boy to death and drove to the outskirts of a town near Indiana. Once there, they doused Franks’ face with hydrochloric acid to hinder identification by the police and hurriedly stashed his naked corpse in a drainpipe.
Later that evening, the killers were back in Leopold’s elegant Hyde Park home. They drank and played cards, interrupting their game around midnight to phone Franks’ family and tell them to expect a ransom note for their kidnapped son. Leopold and Loeb never fathomed they might be caught. These brilliant sons of privileged Chicago families — Leopold reportedly had an IQ of 200; Loeb had graduated from college by age eighteen — believed themselves exempt from the laws that governed ordinary men.
Several days later, their plan unraveled as police found a distinctive pair of horn-rimmed eyeglasses at the crime scene and traced them back to Leopold. Shortly thereafter, the two were indicted on charges of kidnapping and murder. Their parents hired famed attorney Clarence Darrow to defend them for committing what came to be known as “the crime of the century.”
The month-long trial culminated in August 1924 with a bravura summation by Clarence Darrow arguing for life in prison for the two instead of death by hanging:
Why did they kill little Bobby Franks? Not for money, not for spite; not for hate…They killed him because they were made that way. Because somewhere in the infinite processes that go to the making up of the boy or the man something slipped, and those unfortunate lads sit here hated, despised, outcasts, with the community shouting for their blood.
Leopold and Loeb’s actions, in Darrow’s telling, were just part of the natural order of the world: “Nature is strong and she is pitiless… we are her victims,” Darrow intoned. ”Each act, criminal or otherwise, follows a cause [and] given the same conditions, the same result will follow forever and ever.”
In the end, the judge spared Leopold and Loeb the gallows, sentencing each to life in prison for murder plus 99 years for kidnapping — not because they were victims of nature, an argument the judge explicitly rejected, but because of their youth.
Darrow’s plea was remarkable. If “each act follows a cause,” then all of us, not just Leopold and Loeb, are nature’s victims. Bold as it was, however, the claim was not original. It drew on the ancient philosophical doctrine known as determinism, which states that every event is completely caused, or determined, by what happened leading up to it.
Our decisions are the inevitable product of a vast array of influences — our genes (and the evolutionary history they represent), the mechanisms of our brains, our upbringing, and the physical and social environments in which we live. These forces converge to produce one and only one specific act, be it “choosing” soup over salad or murder over mercy. To borrow Darrow’s words, you have “no more power than a machine to escape the law of cause and effect.”
Leopold and Loeb’s “decision” to murder Bobby Franks may have been the only one they could have made that June afternoon in Hyde Park. Still, few of us see them as automatons devoid of conscious thoughts and emotions. We believe instead that they harbored desires and acted for reasons, twisted as those motives were. Granted, their desires were not dispositions that the two men chose to have; nor could they be expected to know everything about why they had them. But in the end, Leopold and Loeb rehearsed their plan and consciously carried out the unspeakable thing they wanted to do.
Could we be wrong about that? Is it possible that Leopold and Loeb really were automatons after all? What if their actions did not flow from their conscious intentions and desires, but suppose, instead, that those actions happened to them, bypassing their conscious awareness entirely? Taking this possibility a step further, might our actions do end-runs around conscious deliberation in all of us all of the time?
This is the startling new challenge that some neuroscientists are introducing to the existence of free will: the possible absence of all consciously directed action. Such a radically reductionist prospect may strike many as outlandish, yet some of today’s most highly respected scientists contend that individuals’ subjective mental states — their yearnings, beliefs, and plans — play absolutely no role in bringing about their actions.
To support this claim, they point to a series of arresting experiments conducted in the 1980s by physiologist Benjamin Libet. In his lab at the University of California at San Francisco, Libet wired subjects to an EEG and asked them to choose a random moment to lift a finger or move their wrist. He instructed them to watch the second hand of a clock and report its exact position when they felt the urge to move. Libet then measured electrical activity in a region of the frontal lobe called the supplementary motor area, which is involved in the planning of movements.
What he found was striking: Activity in the motor area could be detected some 400 milliseconds before subjects were aware of their decision to wiggle their fingers. In other words, the subjects’ conscious awareness of the intention to move occurred too late in the sequence to influence the action. Instead of presaging movement, then, experience of the will to move followed it.
The prospect of a world without moral responsibility collides head-on with our innate sense that people can choose freely.
Libet himself did not consider these results to be a wholesale repudiation of consciousness in guiding behavior. He speculated that while awareness came into play late in the sequence of events, people still had the freedom to “veto” or suppress actions that were caused by implicit processes outside of awareness. Yet others have interpreted his results more radically, as proof that the mind or the person — the entity we think of as ourselves — is not calling the shots.Psychologist Daniel M. Wegner is a proponent of this view. We are so certain that we are in the driver’s seat, he says, because we yearn to feel “authorship” of our actions.
The prospect of a world without moral responsibility collides head-on with our innate sense that people can choose freely. At five years old, most children perceive others’ actions in terms of their intentionality and agency. In one representative experiment, kindergartners observed an investigator sliding open the lid of a box, putting her hand in, and touching the bottom of the box. Asked by the experimenter if she had to touch the bottom or whether she “could have done something else instead,” the vast majority of children believed that yes, she could have done something else. But when the experimenter placed a ball on the lid, slid open the lid, and the ball fell to the bottom of the box, only a few of the children said that the ball itself could have “done something else instead.”
The intuition that people can do something else persists with age. Adults across cultures, religions, and countries steadfastly reject the idea that the decisions we make are fixed in such a manner that no other actions are possible.
Brain imaging, the iconic tool of neuroscience, finds itself at the eye of a perfect storm of seduction. Riding one current is the glamour of a sophisticated and exciting new technology. Borne aloft on another is the brain itself, an organ of great moment and mystery. On a third current floats an overly simplified brain-to-behavior narrative, all rendered in stunning biological portraiture. Tossed by these powerful swells, it is easy to see how non-professionals, and the occasional expert, can get swept away.
The illuminated brain cannot be trusted to offer an unfiltered view of the mind.
Our project is not a critique of neuroscience, nor of its signature instrument, brain imaging. It is an exposé of mindless neuroscience: the oversimplification, interpretive license, and premature application of brain science in the legal, commercial, clinical, and philosophical domains. Secondarily but importantly, it is also a critique of the increasingly fashionable assumption that the brain is the only important level of analysis for understanding human behavior, and that the mind — the psychological products of brain activity — is more or less expendable.
We are unreserved champions of neuro-technological progress. We are certain that it will further elucidate the relationship between the brain and the mind. We deeply admire the neuroscientists whose inquiries are yielding new discoveries and, perhaps soon, much-needed treatments.
However we have tried to bring a circumspect view to practical applications of neuroscience and to speculations about where insights gleaned from brain science may take our society. The illuminated brain cannot be trusted to offer an unfiltered view of the mind. Nor is it logical to regard behavior as beyond an individual’s control simply because the associated neural mechanisms can be shown to be ”in the brain.”
Brain-based explanations for excessive appetites and for social behaviors that elide the crucial psychological, social, and cultural levels of analysis fall into the trap of “neurocentrism.” As such, they are guaranteed to be impoverished explanations. Although scientists can describe human behavior on a number of different levels — the neuronal, the mental, the behavioral, the social — they are not close to bridging the yawning gap between the physical and psychological. The brain enables the mind, and thus, the person. But it cannot yet, if ever, fully explain how this happens.
As brain science continues to permeate the culture, neuroliteracy becomes ever more important. The science of the mind is one of the most important intellectual achievements of the last half-century. But it is young and still getting its bearings. To demand the wrong things of brain science, to overpromise on what it can deliver, and apply its technology prematurely will tarnish its credibility. It also risks diverting crucial and limited resources, including federal funding for research, into less profitable ventures and even blind alleys.
In 1996, author Tom Wolfe penned a widely cited essay, “Sorry, But Your Soul Just Died.” Neuroscience, he wrote, was on “the threshold of a unified theory that will have an impact as powerful as that of Darwinism a hundred years ago.” Almost two decades later, the excitement surrounding neuroscience continues to grow, as well it should. But the promise of a unified theory in the foreseeable future is an illusion. As with sociobiology and the genomic revolution — two valuable conceptual legacies of Darwinism — we should extract the wisdom neuroscience has to offer without asking it to explain all of human nature.
In 2011, science writer David Dobbs recounted a sobering encounter with a table full of neuroscientists. He asked them, “Of what we need to know to fully understand the brain, what percentage do we know now?” They all responded with figures in the single digits. This humbling estimate will improve with time, of course. Brain imaging will become more precise; new technologies are yet to be unveiled or even envisioned. Yet no matter how dazzling the fruits of inquiry or how clever the means by which they are obtained, it is our values that will guide us in implementing them for good or for bad. The danger lies in muddling those values under the pretense of following where neuroscience supposedly leads us.
To some neuroscientists and philosophers, you may be nothing but your brain — and of course without a brain there is no consciousness at all. But to you, you are a “self,” and to others you are a person — a person whose brain affords, at once, the capacity for decisions, the ability to study how decisions happen, and the wisdom to weigh the responsibilities and freedoms that these decisions make possible.
From Brainwashed: The Seductive Appeal of Mindless Neuroscience, by Sally Satel and Scott O. Lilienfeld (Basic Books, 2013).