The literal replay of new information had started to evolve into analysis. Once an initial phase of dreaming passed, the brain began finding connections and associations with the data embedded on its memory cards. This stage of dreaming, which fused elements of skiing with what the subjects already knew, occurred later in the night, a time when the adult brain spends longer amounts of time in REM sleep. As the subjects slept, their brains conducted free-association sessions, desperately searching for connections. That may explain not only why the dreams we remember upon waking up after a long sleep seem so strange, but also how we craft new ideas from our memory. The open interplay of emotions, facts, and fresh information allows our brains to see things in a new way. A golfer waking up with a better way to grip a club suddenly seemed less like a genius, and instead the natural outcome of what sleep does for the brain.
Stickgold’s contention that the brain consolidates information during sleep in order to make new connections was supported by research conducted by one of his former students, a red-headed Englishman named Matthew P. Walker, who is a professor at the University of California, Berkeley. Working off of Stickgold’s research, Walker decided to look at how sleep affected what is known in neuroscience as brain plasticity, which is essentially the way the brain remolds and updates itself when it learns a new skill or stores a new memory. At the time, Walker was fresh from a postdoctoral study at Harvard. He had been part of a team that found that subjects who were tested on their ability to type a string of numbers completed the task 20 percent faster when they were given a chance to sleep before approaching it a second time.
In his work at Berkeley, Walker asked right-handed subjects to type a five-number sequence using their left hands. It was an unfamiliar task that lowered the chances that a subject could skew the data because of his or her natural ability. By analyzing the time that it took them to hit the keys, Walker found that almost all of the subjects subconsciously broke the string of digits into smaller, easy-to-manage chunks, much like you might remember your Social Security number by slicing it into a group of three, two, and four digits. You can hear this process at work when you say your number aloud and find yourself breaking into a singsong rhythm. Walker then had his subjects come back after a night of normal sleep. Just like in the studies of Wilson and Stickgold, time spent sleeping improved performance. After eight hours of sleep, nearly every person in the study typed the numbers in one smooth motion.
Not all sleep gives the brain the same benefits, however. Timing matters. The smoothing effect Walker identified depends on the quality of sleep a person gets immediately after learning something new. The most important period of learning occurs in the first six hours of the night. In one study, researchers trained subjects to perform a motor-skill test. One group was awakened after less than six hours of sleep and trained to perform a second, unrelated task. The other group was allowed to sleep normally. Subjects who did not have their sleep interrupted were able to complete the motor-skill test by an average of 21 percent faster the next day. Those who were awakened, however, improved by an average of only 9 percent. Their brains, it appeared, were interrupted at a crucial time.
In another study, researchers trained subjects to complete a typing exercise. Some subjects were deprived of sleep for one night while the rest were allowed to sleep normally. The next night, however, every person in the study was allowed to sleep as long as he or she wished. By the end of the several-day study, all of the subjects had slept roughly the same total number of hours. Yet even when cumulative sleep hours were more or less equal, a subject’s performance clearly reflected how many hours he or she slept the night after learning the new skill. Those who didn’t get to sleep that first night consistently lagged behind those who did. The brain’s initial shot at consolidating new information into memory mattered more than the simple passage of time, or extra sleep on a second night. The adage that practice makes perfect looked to be only half right. Success depended on practice, plus a night of sleep. “Sleep is enhancing that memory so that when you come back the next day you’re even better than where you were the day before,” Walker says.
But what if you aren’t always able to get a full night’s sleep? After all, many of us sleep fewer hours than we would like to after picking up important information—say, what a client expects to spend on our company’s products next year, or how to use an expensive new computer program—not because we want to but because we are forced to. Does knowing that we have deprived ourselves of a vital time for learning and innovation make it all the worse?
Not necessarily. If you can’t get in a full night’s sleep, you can still improve the ability of your brain to synthesize new information by taking a nap. In a study funded by NASA, David Dinges, a professor at the University of Pennsylvania, and a team of researchers found that letting astronauts sleep for as little as fifteen minutes markedly improved their cognitive performance, even when the nap didn’t lead to an increase in alertness or the ability to pay more attention to a boring task. Researchers at the City University of New York, meanwhile, found that naps helped the brain better assess and make connections between objects. Test subjects in their study were shown pairs of objects and told that they would be tested on their ability to remember them later. One group was given a ninety-minute break to take a nap, while the other group spent that time awake watching a movie. Subjects came back to the testing room expecting to complete the simple memory puzzle. Researchers instead asked them to describe the relationships between the objects that made up each pair, rather than recall the pairs. Again, the amount of time that each subject slept determined how he or she performed on the task.
Subjects who were able to reach deeper stages of sleep demonstrated a better command of flexible thinking, a vital cognitive skill that allows us to apply old facts and information to new situations. Sleep can also help the brain to recognize patterns. In a study conducted by Simon Durrant, a professor at the University of Manchester in England, subjects listened to a short burst of melodic tones. Later, they were asked to recognize when this sequence played during a much longer stretch of music. As in the study by the New York researchers, subjects were divided between those who were able to take a nap and those who weren’t. The amount of time spent in deep, slow-wave sleep during the nap predicted a subject’s later performance. Those who reached deep sleep in the nap had a greater rate of improvement at the task of recognizing the abstract patterns in music than did those who simply stayed awake.
Subjects who have been allowed to take naps have finished mazes faster, have become less emotional when confronted with disturbing images, and have remembered a longer list of words than their peers who hadn’t been allowed to doze off. Scientists currently think that the process of clearing the mind of unnecessary information and honing skills is at work in all stages of sleep. The benefits improve exponentially the longer someone rests.
Naps are even being used to provide a competitive advantage in the workplace. Companies such as Google, Nike, Procter & Gamble, and Cisco Systems have installed designated napping areas in their offices. The idea is that naps may allow engineers and designers to arrive at creative solutions more quickly than they would by staying awake all day. Consultants from companies with names like Alertness Solutions charge thousands of dollars to educate corporate managers and their employees on the importance of sleep and managing fatigue levels while on the job. Only this time, it is not about worker safety. It’s about speeding up the process of manufacturing ideas.
There is one line of work where spending more time sleeping is now seen as a critical part of not only generating creative ideas but also saving lives. It only took a few accidents on the way to get there.
7
The Weapon “Z”
As the sun fell over the desert, the rumble of tanks slowed and then stopped. The men of the Second Armored Cavalry Regiment found themselves surrounded by a sea of sand. It was February 25, 1991, and about fifty hours into the Gulf War, or what wo
uld later be called the Hundred Hour War. In that short amount of time, an international coalition led by the United States had pushed the Iraqi Army out of Kuwait and had it on the run. Throughout the Arabian Desert, Iraqi forces found themselves stuck in slow, outdated tanks that Saddam Hussein had purchased from the Soviet Union. Not long after the sale, the Kremlin realized that the tanks had serious problems with firing accuracy and rushed to upgrade the Soviet fleet, but Saddam apparently hadn’t kept the receipt. Iraqis soon discovered another curious fault of Soviet engineering: when hit, the turrets of their tanks broke cleanly apart from the vehicle and shot into the air, a phenomenon that coalition forces dubbed the “pop-top.” All across the desert, the tops of Iraqi tanks lay smoldering in the sand.
After racing into southern Iraq, the Second Armored Cavalry was told to wait. Another coalition unit had pushed ahead of schedule, and plowing along with them meant there could be a chance of friendly fire. The tanks formed a literal line in the sand and waited in the dark desert night, battered by high winds and heavy rain. It was their first real break after days of combat. Over each of the last five nights, the men had slept less than three hours. Nevertheless, they stood fixed at their stations with night-vision goggles strapped to their heads, staring into the blankness surrounding them. At one in the morning, the first few blips of activity appeared in their sights. The Iraqi forces that unknowingly corresponded to those movements had no idea they were about to run into a row of armed Americans who had the ability to see in the dark. As soon as the U.S. forces confirmed that the vehicles ahead of them were the enemy, they reverted to the unambiguous motto of all tank crews in battle: if it’s ahead of us, it dies.
The night air echoed with the sound of gunfire. During the fight, three tanks on the far right side of the U.S. line were forced out of the pack. They took evasive maneuvers, turning left and right to regain an upper hand. Suddenly, the number of enemy forces seemed to triple. Stuck out of position, the American tanks fired round after round from their twenty-five-millimeter cannons. They destroyed the vehicles in front of them and survived without taking a hit. By the time the shooting stopped, the American forces had destroyed every Iraqi tank, but they had also lost two of their own.
Later, in the briefing room, military planners wondered how Iraqi forces were able to zero in on tanks that were faster, stronger, and equipped with better technology. Throughout the whole war, enemy forces would destroy only about two-dozen American vehicles. Yet here, in a small battle conducted entirely in the middle of a rainy night, there were two down. Was it bad luck? Or were some Iraqi forces equipped with a weapon that the U.S. military didn’t anticipate? A team went to examine the wreckage of the two doomed Bradleys and interviewed their crews, all of whom survived thanks to their fire-retardant suits, which could withstand temperatures up to two thousand degrees. Sifting through the burning metal, investigators soon held the answer: casings from antitank rounds that could have been fired only from a U.S. vehicle. The two tanks had been lost to friendly fire.
It was a scenario that kept playing out across the desert. In the Gulf War, one of every four American combat deaths was a result of fire from U.S. forces. Not long after the war ended, a team of U.S. Army psychologists began to investigate why soldiers kept attacking the wrong people. Like polio or smallpox, friendly fire should have been eradicated by technology and training. In the months leading up to the Gulf War, tank commanders had spent hundreds of hours in simulated battles. Crews inside each tank had laser-guided sensors that could identify a vehicle based on the heat it gave off, while soldiers on the ground carried six-pound packs containing receivers that grabbed information from orbiting satellites so they could pinpoint nearby coalition forces on a map. The fog of war, if not entirely dissipated, should have shown signs of burning off. But the rate of friendly-fire accidents wasn’t falling like it was supposed to.
Something was happening in the midst of battle that soldiers weren’t prepared for and that was leading to casualties. Researchers interviewed soldiers who shot at their own forces and those who were the targets. They pored over training manuals. They built intricate timelines, precise to the second, that detailed when the mistaken shots were fired and what was going through each soldier’s mind at the time. They compared real-world conditions with results gleamed from research studies, considering everything from reaction times to morale.
After all of their digging, one truth stared at them, a conclusion that was as obvious as it was radical: soldiers simply weren’t getting enough sleep. The skills and training built up over hundreds of hours of preparation were lost on the battlefield amid the sleep deprivation of combat. The effects of sleep deprivation were strong enough that they threatened to derail the greatest military organization in the world. The needs of the human body, and the vital role that sleep plays in how the brain makes rational decisions, were trumping the top-secret technology and hardware that should have given U.S. forces total dominance over their enemies.
Men and women in the military fly around the world and do everything but sleep. Their lives are set out to the minute. In combat zones, most soldiers have no say in when they wake up, when they eat breakfast, or when they lie down at night. In peacetime, soldiers will be lucky if they get six hours of rest a night, or about three-quarters of what most adult bodies need to maintain an alert brain. Adolescent bodies—including the thousands of young recruits who are still not old enough to drink legally—often need nine hours of sleep to be fully restored.
Without deep sleep, the brain morphs from being our greatest evolutionary asset to our greatest weakness. During a study of crew members on a U.S. Coast Guard ship traveling from Virginia to Nova Scotia, for instance, researchers found that twelve of fourteen sailors fell asleep at their posts at least once. It would be impossible to put a dollar cost on all of the bad decisions resulting from the hours of lost sleep, but here is one small but telling number: in 1996, a time of relative peace, crew fatigue was blamed for thirty-two accidents that destroyed American military aircraft, including three F-14 jetfighters that cost $38 million each.
Twelve years after the Gulf War, American tanks once again rumbled through the desert of southern Iraq, this time with the purpose of going all the way to Baghdad. War planners had taken into account how much fuel, food, and ammunition each unit would need for Operation Iraqi Freedom to succeed. Sleep, however, wasn’t considered a necessity. The result was an army full of soldiers who had slept only two hours a night during the countdown to war. The dash north from the border of Kuwait stalled several times when drivers behind the wheels of tanks and Humvees fell asleep and veered off the side of the road. The lack of sleep “is our biggest enemy,” one marine colonel said during a break in combat. “It makes easy tasks difficult.”
Officers in combat nevertheless pushed their soldiers to go without sleep, willfully trading the tactical advantages of speed and mobility for the drawbacks built up from fatigue. Sleep deprivation increased up the chain of command. Many officers stayed awake for more than forty-eight hours straight during the first stage of combat, and when they did sleep, they would lie down for only twenty-minute naps at a time. One commander said that he was able to function after sleeping a total of two hours spread over several days because he was “actively fearful of screwing up.”
But fear of failure can take you only so far. Because of rampant sleep deprivation, most men and women in uniform rely on stimulants to stay awake. Chief among them is caffeine. Soldiers guzzle the stuff, starting in boot camp. As they move up the ranks, most graduate from high-caffeine, high-sugar drinks such as Red Bull, Jolt, and neon-green Mountain Dew and turn to super-caffeinated coffee. One popular brand, Ranger Coffee, mixes Arabica coffee beans with additional liquid caffeine. The result is so potent that each bag comes with a label warning that it is not for the faint of heart.
Caffeine is popular as a stimulant because it readily crosses the barrier between the blood and the brain. Once in the brain, it blocks the
absorption of adenosine, a nucleotide that slows down nerve connections and makes you feel drowsy. The result is like being able to drive a car backward to roll back the odometer. In research studies, caffeine helped sleep-deprived subjects better discriminate between colors, sort words according to their meaning faster, and see in the dark more clearly. The effect is so powerful that some soldiers resort to eating frozen coffee grounds to stay awake in the field. In the late 1990s, military researchers received a quarter of a million dollars to develop caffeinated gum as an alternative. Gum is ideal if you really need caffeine in a hurry: it allows the stimulant to be absorbed through the tissues in the mouth and reach the brain about five times faster than a pill or coffee. By the 2001 invasion of Afghanistan, pieces of gum that packed 100 milligrams of caffeine—a little bit more than a shot of espresso at Starbucks—were a standard part of soldiers rations. Packets are currently available to civilians on Amazon.com, each one stamped with the hard-sell slogan “Stay Awake, Stay Alive.”
When caffeine doesn’t do the trick, pharmaceuticals take over. Soldiers in combat have turned to amphetamines since World War II. The military restricts most soldiers from taking the pills—which are essentially speed—without a doctor’s prescription, but they are common among certain occupations. Pilots, for instance, routinely take orange “go pills” before night missions, and sometimes take another dose while in the cockpit. The surge in energy comes with a cost. In addition to making it harder to achieve deep sleep once the effect of the stimulant wears off, taking amphetamines can lead to increased aggression and paranoia. Go pills were cited as a contributing factor in a 2001 accident where two American pilots dropped a bomb on an elite Canadian army unit during a live-fire exercise in a remote area of Afghanistan, killing four of them.
Dreamland: Adventures in the Strange Science of Sleep Page 10
