The Power of Habit: Why We Do What We Do in Life and Business (40 page)

“I honestly believe anyone in my shoes would have done the same things,” Bachmann told me.

On a July morning in 2008, a desperate man vacationing along the west coast of Wales picked up the phone and called an emergency operator.

“I think I’ve killed my wife,” he said. “Oh my God. I thought someone had broken in. I was fighting with those boys but it was Christine. I must have been dreaming or something.
What have I done? What have I done?”
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Ten minutes later, police officers arrived to find Brian Thomas crying next to his camper van. The previous night, he explained, he and his wife had been sleeping in the van when young men racing around the parking lot had awoken them. They moved their camper to the edge of the lot and went back to sleep. Then, a few hours later,
Thomas woke to find a man in jeans and a black fleece—one of the racers, he thought—lying on top of his wife. He screamed at the man, grabbed him by the throat, and tried to pull him off. It was as if he was reacting automatically, he told the police. The more the man struggled, the harder Thomas squeezed. The man scratched at Thomas’s arm and tried to fight back, but Thomas choked, tighter and tighter, and eventually the man stopped moving. Then, Thomas realized it wasn’t a man in his hands, but his wife. He dropped her body and began gently nudging her shoulder, trying to wake her, asking if she was all right. It was too late.

“I thought somebody had broken in and I strangled her,” Thomas told the police, sobbing.
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“
She’s my world.”
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For the next ten months, as Thomas sat in prison awaiting trial, a portrait of the murderer emerged. As a child, Thomas had started sleepwalking, sometimes multiple times each night. He would get out of bed, walk around the house and play with toys or fix himself something to eat and, the next morning, remember nothing about what he had done. It became a family joke. Once a week, it seemed, he would wander into the yard or someone else’s room, all while asleep. It was a habit, his mother would explain when neighbors asked why her son was walking across their lawns, barefoot and in his pajamas. As he grew older, he would wake up with cuts on his feet and no memories of where they had come from. He once swam in a canal without waking. After he married, his wife grew so concerned about the possibility that he might stumble out of the house and into traffic that she locked the door and slept with the keys under her pillow. Every night, the couple would crawl into bed and “have a kiss and a cuddle,” Thomas later said, and then he would go to his own room and sleep in his own bed. Otherwise his restless tossing and turning, the shouting and grunting and occasional wanderings, would keep Christine up all night.

“Sleepwalking is a reminder that wake and sleep are not mutually exclusive,” Mark Mahowald, a professor of neurology at the University
of Minnesota and a pioneer in understanding sleep behaviors, told me. “The part of your brain that monitors your behavior is asleep, but the parts capable of very complex activities are awake. The problem is that there’s nothing guiding the brain except for basic patterns, your most basic habits. You follow what exists in your head, because you’re not capable of making a choice.”

By law, the police had to prosecute Thomas for the murder. But all evidence seemed to indicate that he and his wife had a happy marriage prior to that awful night. There wasn’t any history of abuse. They had two grown daughters and had recently booked a Mediterranean cruise to celebrate their fortieth wedding anniversary. Prosecutors asked a sleep specialist—Dr. Chris Idzikowski of the Edinburgh Sleep Centre—to examine Thomas and evaluate a theory: that he had been unconscious when he killed his wife. In two separate sessions, one in Idzikowski’s laboratory and the other inside the prison, the researcher applied sensors all over Thomas’s body and measured his brain waves, eye movement, chin and leg muscles, nasal airflow, respiratory effort, and oxygen levels while he slept.

Thomas wasn’t the first person to argue that he had committed a crime while sleeping and thus, by extension, should not be held responsible for his deed. There’s a long history of wrongdoers contending they aren’t culpable due to “automatism,” as sleepwalking and other unconscious behaviors are known. And in the past decade, as our understanding of the neurology of habits and free will has become more sophisticated, those defenses have become more compelling. Society, as embodied by our courts and juries, has agreed that some habits are so powerful that they overwhelm our capacity to make choices, and thus we’re not responsible for what we do.

Sleepwalking is an odd outgrowth of a normal aspect of how our brains work while we slumber. Most of the time, as our bodies move
in and out of different phases of rest, our most primitive neurological structure—the brain stem—paralyzes our limbs and nervous system, allowing our brains to experience dreams without our bodies moving. Usually, people can make the transition in and out of paralysis multiple times each night without any problems. Within neurology, it’s known as the “switch.”

Some people’s brains, though, experience switching errors. They go into incomplete paralysis as they sleep, and their bodies are active while they dream or pass between sleep phases. This is the root cause of sleepwalking and for the majority of sufferers, it is an
annoying but benign problem.
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Someone might dream about eating a cake, for instance, and the next morning find a ravaged box of doughnuts in the kitchen. Someone will dream about going to the bathroom, and later discover a wet spot in the hall. Sleepwalkers can behave in complex ways—for instance, they can open their eyes, see, move around, and drive a car or cook a meal—all while essentially unconscious, because the parts of their brain associated with seeing, walking, driving, and cooking can function while they are asleep without input from the brain’s more advanced regions, such as the prefrontal cortex. Sleepwalkers have been known to boil water and make tea. One operated a motorboat. Another turned on an electric saw and started feeding in pieces of wood before going back to bed. But in general, sleepwalkers will not do things that are dangerous to themselves or others. Even asleep, there’s an instinct to avoid peril.

However, as scientists have examined the brains of sleepwalkers, they’ve found a distinction between
sleepwalking
—in which people might leave their beds and start acting out their dreams or other mild impulses—and
something called
sleep terrors
.
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When a sleep terror occurs, the activity inside people’s brains is markedly different from when they are awake, semi-conscious, or even sleepwalking. People in the midst of sleep terrors seem to be in the grip of terrible anxieties, but are not dreaming in the normal sense of the word. Their
brains shut down except for the most primitive neurological regions, which include what are known as “central pattern generators.” These areas of the brain are the same ones studied by Dr. Larry Squire and the scientists at MIT, who found the neurological machinery of the habit loop. To a neurologist, in fact, a brain experiencing a sleep terror looks very similar to a brain following a habit.

The behaviors of people in the grip of sleep terrors
are
habits, though of the most primal kind. The “central pattern generators” at work during a sleep terror are where such behavioral patterns as walking, breathing, flinching from a loud noise, or fighting an attacker come from. We don’t usually think about these behaviors as habits, but that’s what they are: automatic behaviors so ingrained in our neurology that, studies show, they can occur with almost no input from the higher regions of the brain.

However, these habits, when they occur during sleep terrors, are different in one critical respect: Because sleep deactivates the prefrontal cortex and other high cognition areas, when a sleep terror habit is triggered, there is no possibility of conscious intervention. If the fight-or-flight habit is cued by a sleep terror, there is no chance that someone can override it through logic or reason.

“People with sleep terrors aren’t dreaming in the normal sense,” said Mahowald, the neurologist. “There’s no complex plots like you and I remember from a nightmare. If they remember anything afterward, it’s just an image or emotions—impending doom, horrible fear, the need to defend themselves or someone else.

“Those emotions are really powerful, though. They are some of the most basic cues for all kinds of behaviors we’ve learned throughout our lives. Responding to a threat by running away or defending ourselves is something everyone has practiced since they were babies. And when those emotions occur, and there’s no chance for
the higher brain to put things in context, we react the way our deepest habits tell us to.
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We run or fight or follow whatever behavioral pattern is easiest for our brains to latch on to.”

When someone in the midst of a sleep terror starts feeling threatened or sexually aroused—two of the most common sleep terror experiences—they react by following the habits associated with those stimuli. People experiencing sleep terrors have jumped off of tall roofs because they believed they were fleeing from attackers. They have killed their own babies because, they believed, they were fighting wild animals. They have raped their spouses, even as their victims begged them to stop, because once the sleepers’ arousal began, they followed the ingrained habit to satisfy the urge. Sleepwalking seems to allow some choice, some participation by our higher brains that tell us to stay away from the edge of the roof. Someone in the grip of a sleep terror, however, simply follows the habit loop no matter where it leads.

Some scientists suspect sleep terrors might be genetic; others say diseases such as Parkinson’s make them more likely. Their causes aren’t well understood, but for a number of people, sleep terrors involve violent impulses. “Violence related to sleep terrors appears to be a reaction to a concrete, frightening image that the individual can subsequently describe,” a group of Swiss researchers wrote in 2009. Among people suffering one type of sleep dysfunction, “attempted assault of sleep partners has been reported to occur in
64% of cases, with injuries in 3%.”
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In
both the United States and the United Kingdom, there is a
history of murderers arguing that sleep terrors caused them to commit crimes they
would have never consciously carried out.
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Four years before Thomas was arrested, for instance, a man named Jules Lowe was found not guilty of murdering his eighty-three-year-old father after claiming that the
attack occurred during a sleep terror.
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Prosecutors argued it was “far-fetched in the extreme” to believe that Lowe was asleep while he punched, kicked, and stamped his father for more than twenty minutes, leaving him with over ninety injuries. The jury disagreed and set him free. In September 2008, thirty-three-year-old Donna Sheppard-Saunders nearly suffocated her mother by holding a pillow over her face for thirty seconds. She was
later acquitted of attempted murder by arguing that she had acted while asleep.
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In 2009, a British soldier admitted to raping a teenage girl, but said he was asleep and unconscious while he undressed himself, pulled down her pants, and began having sex. When he woke, mid-rape, he apologized and called the police. “I’ve just sort of committed a crime,” he told the emergency operator. “I honestly don’t know what happened. I woke up on top of her.” He had a history of suffering from
sleep terrors and was found not guilty.
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More than 150 murderers and rapists have escaped punishment in the past century using the automatism defense. Judges and juries, acting on behalf of society, have said that since the criminals didn’t
choose
to commit their crimes—since they didn’t consciously participate in the violence—they shouldn’t bear the blame.