I am not a memory champion, but I will give it my best shot regardless Mind you, it will be a lengthy shot.
First I want to get a little misunderstanding out of the way, as you are actually never really talking about short term memory. You might put this under nitpicking, but you will see why this understanding is important.
Memory palaces, pegs, number systems, etc are all methods that can be used to improve the retention of abstract information in a way that allows for both recovery of the information, and in most cases recovery of order. This is all long term memory.
Short term memory is information that always gets forgotten after 15-30 seconds, all information that doesn’t, is moved to the long term memory. However, some memories stick around for longer than others. This is why it is important to know that we are not focussing on different aspects of memory, but on different aspects of long term memory:
- Memories that stick around for a short time (hours or days)
- Memories that stick around for a long time (months or years)
Let’s start by looking at the memories that we naturally develop. I still know a time from when I was 8. It was picture day at school, and I brought my stuffed turtle. The photographer told me I could not get my picture taken with the stuffed turtle. I said I could. He said I couldn’t. I said I could. My teacher said I could. The photographer took the picture against his will.
Why do I remember that? Four main aspects I often find to influence long term memories are Focus, Sensation, Familiarity and Repetition. Whichever is the strongest is different per person, but they all influence it.
Focus: I was in that moment. I wanted the picture to be with my turtle so you could put money on it that I was going to do that. I was not going to take no for an answer, and that photographer was going to break before 8-year old me did.
To apply this to your memories, Focus brings it a little further than just our regular image of focus. It a deepening of your understanding. I did not focus on getting that picture taken with my turtle, I focussed on making sure the photographer would allow me to get my picture taken with that turtle. There is a deeper level of focus. Just like that, it is not enough to focus on the words on the page, you want to focus on the subject. You want to deepen your understanding of it, you want to turn the subject into the story most subjects are (more on this at Familiarity)
Sensation: I loved my turtle, and I hated that photographer. Those emotions, among others, can make for a very strong memory. However, this is weak in my brain. My brain does not care about emotions, and that results in a lot of things that my memory has trouble with. I suck at remembering people, and I suck at remembering what people are like. As a kid, I also burned my hand to the stove twice, because my mind did not create a memory of the pain the first time.
Sensation can refer to emotions, but also to senses. When reading replies to those starting out with memory palaces you will often read people to create a memorable, vivid interaction. That plays on this. The more senses you involve, the stronger the image generally becomes. A similar thing happens with emotions. The stronger your emotion, the stronger the memory. My speed run images stick around for maybe half a day, but images that I put time and effort in (and not overwrite), are capable of sticking around for a few days.
Familiarity: It was my favorite stuffed animal, so it was important to me. The memories attached to it are strong. That is the power of Familiarity, remembering through connection.
This is at the core of memory palaces and peg systems, you want to create images that you know, in order to attach information you don’t know. Our memories don’t float around aimlessly. They are either attached to something, or they vanish into eternal forgottenness. This in combination with Focus alone makes for a strong memory. If you can get a deep understanding of a subject that you can attach to something you know, it will stick around for a decent time.
Repetition: I did not do this more often, but I did have a lot of stories connected to my stuffed animals and toys. While my turtle stands on the clear top, I had multiple toys that I loved and thus multiple memories of a similar kind. That is what the repetition means.
It is often put at the core of methods like Anki, you repeat information. However, I believe that Anki is more Familiarity than Repetition in the sense I mean it here. Every time you create new memories, you create a new hook to attach a new memory to. That is because I am not talking about the repetition of inserting information and retracing the neural connections. With repetition, I mean practice and creating the kinds of memories you want to create more often. Not repetition of the information, but repetition of the memorizing process. While actually training your full memory (without using mnemonics) is tough, you can prime your brain to remember a certain kind of information.
When actually wanting to remember something for months or years, you need to put actual repetition (so yes, here you are repeating, reciting and reenforcing the information), and a bit of luck.
Luck meaning that some memories stick easier than others. I met people that I will never forget, I don’t know why, I don’t know how, they just manage to stick around. I also met people a couple dozen times and after a few weeks they have vanished from my mind.
Last but not least, I want to mention the “instant recall” you briefly brought up. A lot of memories are not instant. I often describe it as front memories and back memories. Front memories are easy to find, names of family, the code you enter when using your bank card, your phone number maybe even. Back memories require effort to find, like the phone number of your partner or the physics equations you learned in high school. All memories start out as back memories, and it requires time and recalling to put them to the front.