In China I saw lots of schools with kids strewn across floors, fast asleep in the early afternoon. It’s a long tradition in China and has more than a touch of ancient wisdom. Science is now showing that a nap after lunch has a positive impact on memory, and therefore learning.
Sleepers learn better
Mathew Walker of the University of California, divided 39 students into two groups; both took a learning task at noon, one group slept for 90 mins at 2pm, the other stayed awake. Both took an assessment at 6pm.
The ‘sleepers’ not only did better than the non-sleepers, they performed better than they did in the first test. If the nap includes REM sleep, a clearing of the memory pathways seems to happen, "It's as though the email inbox in your hippocampus is full and, until you sleep and clear out those fact emails, you're not going to receive any more mail. It's just going to bounce until you sleep and move it into another folder." In other words, short-term memory is clear during REM, which prevents interference with long term consolidation. An intriguing hypothesis is that our memories may get worse as we get older simply because we sleep less. Walker is now investigating this hypothesis. Interestingly, staying up all night seems to reduce memory capability, and therefore learning, by up to 40%. Cramming can therefore be counterproductive.
Bed sharing with siblings, reading, radio, computer games, TVs and mobile phones may keep children up, limiting recovery time while sleeping, also affecting memory and learning.
Mary Carskadon, the queen of sleep research in teenagers, cites several advantages for teens to get the sleep they need:
- less likelihood of experiencing depressed moods;
- reduced likelihood for tardiness;
- reduced absenteeism;
- better grades;
- reduced risk of fall asleep car crashes; and
- reduced risk of metabolic and nutritional deficits associated with insufficient sleep, including obesity.
In a 1998 survey of more than 3,000 high-school students, for example, psychologists Wolfson and Carskadon found that students who reported that they were getting C's, D's and F's in school obtained about 25 minutes less sleep and went to bed about 40 minutes later than students who reported they were getting A's and B's.
Teenagers actually need more sleep than adults and late nights and early schools starts may be harming their learning and general health. Starting around the beginning of puberty and continuing into their early 20s, Carskadon and colleagues have shown, adolescents need about 9.2 hours of sleep each night, compared with the 7.5 to 8 hours that adults need. "Almost all teenagers, as they reach puberty, become walking zombies because they are getting far too little sleep," comments Cornell University psychologist James B. Maas, PhD, one of the nation's leading sleep experts. This research actually led to action with Lofgren's "Zzzzz's to A's" bill, first introduced in the U.S. House of Representatives.