Contrary to the impression you may get if you read popular books by cognitive psychologists, we know almost nothing about memory. We know quite a few things about what happens when people try to remember and how they forget, but exactly what happens in the brain when people try to memorise something is a complete mystery.
The most common way in which most people think about memory is as some sort of storage into which you reach with your mind and retrieve what you are looking for. But the truth is, we just don’t know if that is what memory is like. There are some aspects of memory that behave like storage, but there are others that are very different.
Pretty much everything that we say about memory is some kind of metaphor. Metaphors can be incredibly useful but we should be careful about drawing inferences from them. Here, I will use the metaphor of an inventory of mental schemas from which we retrieve chunks onto a sort of mental shelf where we can combine them into a useful product. But that is all it is - a metaphor.
The storage metaphor breaks down very often. Memory simply does not seem to behave like a storage of objects in many ways. For example, It does not seem to run out of space in a straightforward way. The more we put in, and the more we make connections between what we had placed there, the more seems to be able to fit in. Also, we can often retrieve things from the back of this metaphorical storage more easily than from the front. That is not how storage spaces work in the literal sense. So we must be incredibly careful about what we say when it’s time for things like long-term and short-term memory.
While we know very little about the exact nature of memory, we know even less about what is actually stored in there. We do know what the things that come out look like: Words, memories, ideas, images, episodes, etc. But it is pretty unlikely, they are just stored somewhere in a neuron in a brain for us to retrieve. We wouldn’t know where to start finding the boundaries.
The problem with memory as storage is that we have no easy way to explain how those memories get into working memory. And we also do not know how the sort of practice we do, would put them in the storage in a way that is actually useful when we need them. What sort of things am I pulling out of my head as I am writing this sentence? What did it take for me to put them there? English is not my first language, so it took a long time to learn all the structures, but I also had to learn to type fast enough to do it, the rules of spelling and so on. Individually, it is a long list of things, yet, they seemingly just happen. We do not have a very good theory of what is happening here other than just waving a hand to say that we’re retrieving items.
One way of resolving this problem is thinking about what is in our brain as an inventory of embodied mental schemas. This may seem like an unnecessary diversion but it is actually important as we contemplate what we practice and why. But feel free to skip this section.
We need to answer three questions:
We tend to think that the words in our head are very simple. But they are not - they come with a lot of underlying knowledge. Adjectives are a useful example. We take the colour green. When I something important is happening when I say ‘green leaf’ or a ‘green car’. When I tear apart a leaf, I expect to still see the colour green. Yet, when I open the door of a green car, I expect to see no green at all. Green cars are green on the outside, leaves all the way through. To combine the colour green with the word car is very different from combining it with the word leaf.
What comes into play is our knowledge of the world. Leaves are green through and through, and cars are green only when painted. This is just one tiny thing about leaves and cars, yet, it would take pages to adequately describe it. But we understand both instantly and make the right inferences. So, a good way of thinking about this is as having relatively schematic outlines of things in our head that we can then use instantly but fitting multiple ones together into one.
The same goes for nouns, verbs and other things. All books are different but I don’t have a problem recognising all of them as book. Everybody runs differently (people, animals), yet I can immediately recognise something as running. So, what is in my head doesn’t make sense as a perfect picture, it is some sort of an outline.
Even grammar rules are such outlines. I don’t have a rule in my head that tells me Noun + Verb make a sentence (a dog runs). I have a schema that may look something like this: [[nouny thing][verby things]]. These schemas can get quite large but it seems we are able to use them. (There is a whole theory behind this called construction or cognitive grammar, but that is not too relevant, here.)
This is very useful because, when I practice, my aim is to create ever larger schemas that I can instantaneously combine as I perform. It makes no sense to develop structures that are too specific.