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Why do we need sleep?

A lot of theories have been thrown up over the years as to what we need sleep for (to keep us wandering out of our caves and being eaten by sabertooth tigers, is one of the more entertaining possibilities), but noone has yet been able to point to a specific function of the sleep state that would explain why we have it and why we need so much of it.

In the last part I talked about retrieval structures and their role in understanding what you’re reading. As promised, this month I’m going to focus on understanding scientific text in particular, and how it differs from narrative text.

One of the points I mention in my book on notetaking is that the very act of taking notes helps us remember — it’s not simply about providing yourself with a record. There are a number of reasons for this, but a recent study bears on one of them. The researchers were interested in whether physically writing by hand has a different effect than typing on a keyboard.

How many words do you need to learn?

An analysis of English vocabulary* has found that the first 1000 words account for 84.3% of the words used in conversation, 82.3% of the words encountered in fiction, 75.6% of the words in newspapers, and 73.5% of the words in academic texts. The second 1000 accounts for about another 5% (specifically, 6% of conversation, 5.1% of fiction, 4.7% of newspapers, 4.6% of academic texts).

Children learn. It’s what they do. And they build themselves over the years from wide-eyed baby to a person that walks and talks and can maybe fix your computer, so it’s no wonder that we have this idea that learning comes so much more easily to them than it does to us. But is it true?

There are two particular areas where children are said to excel: learning language, and learning skills.

As we all know, rhyme and rhythm help make information more memorable. Here's a few ideas that may help you use them more effectively.

Rhythm and rhyme are of course quite separate things, and are processed in different regions of the brain. However, they do share some commonalities in why and how they benefit memory. Rhyme and rhythm impose pattern. For that reason, rhyme and rhythm are particularly valuable when information is not inherently meaningful.

Because it holds some personal resonance for me, my recent round-up of genetic news called to mind food allergies. Now food allergies can be tricky beasts to diagnose, and the reason is, they’re interactive. Maybe you can eat a food one day and everything’s fine; another day, you break out in hives. This is not simply a matter of the amount you have eaten, the situation is more complex than that.

I don't think anyone's going to try arguing that fruit and vegetables are not good for your health! We know they're good. But that's just general "oh, I know it's good for me" — do you know that the benefits are not only for your general health, your protection against obesity and diabetes, cancer and heart disease, but also for your brain. Actually, there's two aspects to this. An unhealthy diet (one rich in junk food, in saturated fat and sugar) is actively bad for your brain, and (the right) healthy diet is actively good for your brain.

What do we mean by word-finding problems?

Here are some examples:

  • increasing use of circumlocutions rather than specific terms (e.g., "I wonder where the thing that goes here is")
  • use of empty phrases, indefinite terms, and pronouns without antecedents (i.e., referring to something or someone as "it" or "him / her" without first identifying them by name)
  • increased frequency of pauses

These problems are all characteristic of Alzheimer's, but also, to a much lesser extent, of normal aging.

What mnemonics are, and what they are for

Aids to memory such as acronyms, rhymes, linking information by creating visual images or making up a story, are called mnemonics. Mnemonic strategies have been recommended as appropriate for remembering the following types of information: