10 year old Neha (name changed) stays in the same building as I do. Everyday, she is supposed to learn an amazing amount of facts. New facts of science and geography, rules of mathematics, dates in history and words in English, are just few of the things she learns everyday in school. Add to that everything she talks to her friends and teachers and all the new movements she does while playing, it’s a huge pile of things to learn and remember. But she has an invaluable friend to help her in this difficult job. It’s called Sleep.
After saying goodnight to everybody in the house, Neha goes to sleep at 10 o’clock in the night. As she sleeps peacefully under her Tom and Jerry blanket, a fascinating process starts in her little brain.
Neha’s brain, like all human beings, keeps memories in two different baskets. We learn many new things every minute. As they come in, they are first stored in Short Term Memory basket. The things in Short Term Memory don’t last long. They fade in a few seconds, but repeating them verbally makes them strong, giving rise to the practice of Rutting.
The other basket is Long Term Memory. Memories here stay forever. When we suddenly remember the fond smell of new books from our schooldays, we are using the Long Term memory. Some of the things in Short Term Memory are shifted to Long Term Memory, rest are forgotten.
Short Term Memory has a limited capacity. So when Neha learns all those facts, rules and dates, her Short Term Memory gets full. New incoming facts will be turned away now, just like your email bounces when the mailbox gets full.
But sleep comes to rescue. During sleep, the Short Term Memory is cleared, memories not only get shifted to Long Term Memory, but are also carefully arranged along with older memories.
So sleep helps Neha in two ways. It clears her Short Term Memory for new learning, and creates good Long Term memories. Most of this work happens in the second half of the sleep.
And that’s why early start that most schools have can be a problem. If the child is sleeping late, and rising early for school, the precious hours of sleep doing this housekeeping work may be lost. Some schools in countries like the US have actually modified their start time to allow children to sleep more.
This clearing of Short Term Memory is important for us working adults too. This is where the afternoon naps come in. But more on that some other time. I have to take a nap now.