We go to college to learn, to soak up a dazzling array of information intended to prepare us for adult life. But college is not simply a data dump; it is also the end of parental supervision. For many students, that translates into four years of late nights, pizza banquets and boozy weekends that start on Wednesday. And while we know that bad habits are detrimental to cognition in general—think drunk driving—new studies show that the undergrad urges to eat, drink and be merry have devastating effects on learning and memory. It turns out that the exact place we go to get an education may in fact be one of the worst possible environments in which to retain anything we've learned.
Dude, I haven't slept in three days!
Normal human beings spend one-third of their lives asleep, but today's college students aren't normal. A survey of undergraduates and medical students at Stanford University found 80 percent of them qualified as sleep-deprived, and a poll taken by the National Sleep Foundation found that most young adults get only 6.8 hours a night.
All-night cramfests may seem to be the only option when the end of the semester looms, but in fact getting sleep—and a full dose of it—might be a better way to ace exams. Sleep is crucial to declarative memory, the hard, factual kind that helps us remember which year World War I began, or what room the French Lit class is in. It's also essential for procedural memory, the "know-how" memory we use when learning to drive a car or write a five-paragraph essay. "Practice makes perfect," says Harvard Medical School psychologist Matt Walker, "but having a night's rest after practicing might make you even better."
Walker taught 100 people to bang out a series of nonsense sequences on a keyboard—a standard procedural memory task. When asked to replay the sequence 12 hours later, they hadn't improved. But when one group of subjects was allowed to sleep overnight before being retested, their speed and accuracy improved by 20 to 30 percent. "It was bizarre," says Walker. "We were seeing people's skills improve just by sleeping."
For procedural memory, the deep slow-wave stages of sleep were the most important for improvement—particularly during the last two hours of the night. Declarative memory, by contrast, gets processed during the slow-wave stages that come in the first two hours of sleep. "This means that memory requires a full eight hours of sleep," says Walker. He also found that if someone goes without sleep for 24 hours after acquiring a new skill, a week later they will have lost it completely. So college students who pull all-nighters during exam week might do fine on their tests but may not remember any of the material by next semester.
Walker believes that the common practice of back-loading semesters with a blizzard of papers and exams needs a rethink. "Educators are just encouraging sleeplessness," says Walker. "This is just not an effective way to force information into the brain."
Who's up for pizza?
Walk into any college cafeteria and you'll find a smorgasbord of French fries, greasy pizza, burgers, potato chips and the like. On top of that, McDonald's, Burger King, Wendy's and other fast-food chains have been gobbling up campus real estate. With hectic schedules and skinny budgets, students find fast food an easy alternative. A Tufts University survey found that 50 percent of students eat too much fat, and 70 to 80 percent eat too much saturated fat.
But students who fuel their studies with fast food have something more serious than the "freshman 15" to worry about: They may literally be eating themselves stupid. Researchers have known since the late 1980s that bad eating habits contribute to the kind of cognitive decline found in diseases like Alzheimer's. Since then, they've been trying to find out exactly how a bad diet might be hard on the brain. Ann-Charlotte Granholm, director of the Center for Aging at the Medical University of South Carolina, has focused on trans fat, widely used in fast-food cooking because it extends the shelf life of foods. Trans fat is made by bubbling hydrogen through unsaturated fat, with copper or zinc added to speed the chemical reaction along. These metals are frequently found in the brains of people with Alzheimer's, which sparked Granholm's concern.
To investigate, she fed one group of rats a diet high in trans fat and compared them with another group fed a diet that was just as greasy but low in trans fat. Six weeks later, she tested the animals in a water maze, the rodent equivalent of a final exam in organic chemistry. "The trans-fat group made many more errors," says Granholm, especially when she used more difficult mazes.
When she examined the rats' brains, she found that trans-fat eaters had fewer proteins critical to healthy neurological function. She also saw inflammation in and around the hippocampus, the part of the brain responsible for learning and memory. "It was alarming," says Granholm. "These are the exact types of changes we normally see at the onset of Alzheimer's, but we saw them after six weeks," even though the rats were still young.
Her work corresponds to a broader inquiry conducted by Veerendra Kumar Madala Halagaapa and Mark Mattson of the National Institute on Aging. The researchers fed four groups of mice different diets—normal, high-fat, high-sugar and high-fat/high-sugar. Each diet had the same caloric value, so that one group of mice wouldn't end up heavier. Four months later, the mice on the high-fat diets performed significantly worse than the other groups on a water maze test.
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