THE TEACHING ECONOMIST - William A. McEachern                 

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Issue 21, Fall 2001

William A. McEachern, Editor

Teach Me, I Dare You

In the comic strip "Zits" (8/31/01), Jeremy, the teenage character, slumps in his classroom chair and muses to himself as he adjusts his pose: "Half-lidded, cynical eyes, slack-jawed look of boredom - Okay, I'm ready. Teach me. I dare you."

As teachers, we have seen Jeremy's pose all too often.

What's his problem? It could be that Jeremy and millions of students like him simply aren't getting enough sleep. William C. Dement, a leading authority on sleep and head of Stanford's sleep disorder center, writes in The Promise
of Sleep
that forty years of research has convinced him that sleep is the most important prerequisite to learning. "When students are sleeping sufficiently, they are alert, interested, and ready to soak up knowledge." (Complete references on sleep appear in the bibliography on the back page of this issue.)

Dement points out that entering freshmen have abundant information about nutrition and physical fitness but learn virtually nothing about the value of sleep. He found that 80% of the undergraduates at Stanford were "dangerously sleep deprived." The first casualty, he says, is motivation, the key to learning and creativity. Sleep deprivation also affects mood, concentration, memory, error rate, and other measures of cognitive performance, and is manifested by fatigue, irritability, difficulty studying, reduced productivity, and a tendency to make mistakes (does any of this ring a bell?).

His students "report again and again that learning doesn't seem so hard when their minds are no longer weighed down by a sleep debt." For example, after getting eight hours of sleep a night for two weeks, one student found that her "very dull" professor had miraculously become "much more interesting." This reminds me of the Chinese proverb, "When the student is ready, the teacher appears."

Experiments suggest that sleep helps the brain form long-term memories and that interfering with sleep hinders that process. Sleep also affects the transfer of information between short-term and long-term memory. Robert Stickgold, of Harvard Medical School, and his colleagues find that when people learn a new skill, their performance does not improve unless they get more than six - and preferably eight - hours of sleep. And a good night's sleep continues to pay dividends. Well-rested students tested two days to a week after training could perform the new task even better, whereas other students showed no improvement. Without sufficient sleep, skills and factual information may not be properly encoded into the brain's memory circuits.

Stickgold notes that many college students suffer from what he calls "sleep bulimia," getting only three to five hours sleep a night during the week, then bingeing on sleep during weekends trying to catch up. But much of what students "learn" during a sleep-deprived week does not get well integrated into the brain's memory circuits. Worse still, binge sleeping resets their circadian clock so students can't get to sleep Sunday night. Researchers are also finding that sleep deprivation may harm immune and endocrine systems. Symptoms of these problems often are misdiagnosed as a virus, depression, stress, or the effects of changing metabolism.

In a survey of 1,000 adults reported recently by the National Sleep Foundation, young adults showed more signs of sleep deprivation than did other adults. When compared to adults age 30 and over, a significantly larger percentage of 18-to-29-year-olds reported getting up tired, getting less sleep than they did five years earlier, and driving while drowsy.

Incidentally, young drivers learn nothing about the dangers of driving drowsy, yet thousands die or kill others each year because they fall asleep at the wheel. People under the age of 25 represent 55% of drowsy driving fatalities. Research just published in the journal Accident Analysis and Prevention finds through simulations that being awake three hours past one's bedtime diminishes driving ability as much as being legally drunk.

Sleep seems to be the residual factor in balancing the competing demands for time - what's left over after other claims are settled. The problem of sleep deprivation among young people may not be new, but it seems to be getting worse. What's changed in the last few years is that the Internet, cable TV with hundreds of channels, part-time jobs, and the emergence of a 24/7 world have raised the opportunity cost of sleep. One college that monitored student online use found that demand peaked at midnight, and the computer crush of the week occurred Sunday at midnight. Caffeine may be the drug of choice in staying awake (Hellooo Starbucks! The number of coffee bars has more than quadrupled in the last decade).

In the fall of 1997, to address the problem of drowsy students, the starting time at the seven high schools in Minneapolis was changed from 7:15 a.m. to 8:40 a.m. Critics argued that students would simply stay up later. But researchers found that students were sleeping about an hour more and said they were no longer struggling to get out of bed in the morning. After the switch students behaved better in school, had better attendance, and showed fewer signs of depression.

There has been surprisingly little work by economists on this time allocation problem (for an exception, see the article by Daniel Hamermesh). Tiger Woods said that the best thing about leaving for the PGA tour after his second year at Stanford (where he was majoring in economics) is that he now gets enough sleep. More generally, I've noticed how tournament contenders, when interviewed on the eve of the final round, often talk about how much sleep they plan to get. The pros know about the value of sleep.

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