There are many kinds of memory: long term memory, mid-term memory and short term memory.
This one’s also called “working memory”, and it’s vital.
Most people have a working memory of between five and nine spaces that can be filled with numbers, words, and so on.
That’s for short term. The thing is, this memory is usually related to intelligence. And that’s for a reason. It can be compared to the RAM or the speed of a computer.
This means that working memory helps you to think faster and to think deeper.
Imagine you’re a philosopher. You have to juggle in your head with many abstract terms at the same time: definitions, examples, arguments for and against…
And many times you can’t write them down, either because you’re not a word thinker, either because the simple change of subject resets your working memory, causing you to forget your brilliant idea.
Of course, that’s a big problem. So you want to keep your short term memory sharp.
Well, by using it, of course!
You can crutch it with paper and pencil, of course, and that would be very, very useful. Personally, I do it often. But you can not do it.
Today, for example, I had a hard time grasping a physics concept about different times and relativity and movement. Since it involved time flow and movement (and I was walking on the street, too) I couldn’t write it down on paper (and the drawing I did on the sand didn’t help either, and made people look at me strange), so I had to use all my RAM to think about it. Eventually, I got to the concept. I still can’t make it words, but hey! I understand it! And I solved the problem!
And that’s something.