> Caesar was said to prefer the company of fat men, with the implied causation that happy -> fat.
From WikiQuote [0]: "It is not the well-fed long-haired man I fear, but the pale and the hungry looking."
And from pg's determination essay [1]: "That's why Julius Caesar thought thin men so dangerous. They weren't tempted by the minor perquisites of power."
I've never tried the PAO system, due to the startup costs of pre-memorizing 100 person-action-objects.
But a simpler alternative which requires less work up front is the Major System (sometimes called the Phonetic system) [0].
The way it works it by assigning each digit a sound-value (or family of sounds). To remember a number, you then convert the digits to the letter-sounds, and fill in vowels that don't have a digit value to create words.
E.g. to remember Boltzmann's constant, I do this:
1.38 x 10^-23
1 has the letter value "t" or "d". So I use the word "tea" ("e" and "a" have no digit value), to remember the digit 1.
The 38 is converted to "m" and "v", which becomes "movie".
23 becomes "n" and "m", or "nemo", the fish from Finding Nemo.
Putting it all together it becomes: Ludvig [1] walking on bolts (= Ludwig Boltzmann), and in his right hand he's holding a old VHS movie on top of which balances a cup of hot tea. In his left hand he holds a frozen (to indicate the negative sign in the exponent) Nemo.
To make it memorable you can make this scene as vivid as possible: Ludvig is a cautious character who sniffles a lot; walking on bolts would hurt and make it difficult to balance the cup of tea on top of the movie; the frozen fish would be cold and slippery in the hand; the tea would smell nice; etc.
Robert Bjork [0] talks a lot about this, in particular in [1], and also in his 1h long lecture "How we learn vs how we think we learn" [2].
It's important to distinguish between "performance" (how well you're doing right now) vs "learning" (how well you do after some time delay).
Compare blocked practice with interleaved practice. Suppose you're practicing calculating the area of different geometric figures of types A, B, C, etc.
Blocked practice means you do problems in the order of: AAAABBBBCCCC, etc.
Interleaved practice means you mix them up: ACCBAABACA, etc.
Blocked practice increases your performance (how well you're doing right now) because problems of the same type cluster together, i.e. you're able to "cache" the right formula and just plug in the numbers. But this doesn't help learning, because you're not practicing recognizing what features of the figure should prompt you to retrieve which formula from memory.
Interleaved practice reduces your performance, because more cognitive effort is required to retrieve the right formula, you might get it wrong, etc. But it improves learning, because you're training yourself to recognize which figure requires which formula.
So "desirable difficulties" can be introduced (of which interleaving is one) to increase learning at the cost of reducing performance.
> The problem with skipping memorization of concepts after having understood something is that two months later, you'll have forgotten those concepts.
The key realization, for me, is that conceptual understanding, intuitions, and key insights are themselves just pieces of information that can be memorized.
E.g.: Q: How to derive Bayes' Theorem? A: Write P(A and B) two different ways.
The ancient Romans and Greeks were known to use the Memory Palace technique, as other commenters here have mentioned. (It's mentioned by Cicero, in Ad Herrenium (of unknown authorship), and St. Augustine, among others.)
This was continued into the middle ages, by e.g. Christian monks, see Mary Carruthers' work [0], and the Rennaisance (e.g. Matteo Ricci), see e.g. Frances Yates.
For non-western uses of the memory arts, I'd recommend Lynne Kelly. She writes about aboriginal Australians' use of songlines, the African Luba people's use of lukasas, etc. (Lynne Kelly has done multiple podcast interviews that make for fascinating listen, as she's both an accomplished practitioner of the memory arts as well the history behind them.)
It would be so cool if the Native Americans independently discovered the Method of Loci (or something similar)! If so, I wonder if they also developed the same rules of thumb as the Greeks/Romans, like: space your loci apart, always view your loci from the same angle, store a fixed number of items at each loci, etc.
I'm aware of one interesting example where someone created a memory palace around an object that's not a building (or a route along a street). IIRC a person became blind and wanted to write a book, so s/he stored plot points at different parts of an intricate vase s/he was familiar with. (In medieval Europe, the fingers of the left hand were also used for memory purposes.)
Using a stylized bird gives you readily apparent loci: the beak, the head, each of the three feathers of each wing, etc.
Magnifying the bird and turning it into a path is clever, since your sense of place, amount of fatigue while walking, and on which side the sun hits you, would all help cement the route in your memory.
Thomas Bradwardine (1300-1349) recommends combining the two techniques. I.e. at each Loci you link together more than one item using the story mnemonic.
> I think specifically I would second guess myself for the syntax of the cards I was creating - and if there was another better way to do it.
This kind of perfectionism has also been bothering me. ("I need to write the card perfectly, or else it's not even worth doing or even actively harmful.") But there's a couple of points worth remembering to change this belief:
1) If a card is bad, you will notice it when reviewing. It will be difficult to remember (i.e. you will fail the card often compared to other cards); it will be annoying to review (there's a general sense of "ugh" and/or confusion when you see the card); it will be unexpectedly time consuming to review, etc.
2) Bad cards can always be refactored. You can suspend the card (where the card is still in the database, but removed from the learning queue); reword; or split into multiple cards.
Michael Nielsen [0] gives an example of a card which asked for the syntax for creating a symbolic link in Linux. He always messed up the order of the filname/linkname, so he created an additional card that explicitly asked for the order of the filname/linkename in the ln-command.
3) The only way of learning how to make good cards is by just starting making cards, and then noticing which ones don't work.
When a card doesn't stick, it's useful to ask yourself what doesn't work and why. Is the back side surprising when you reveal it? If so, maybe rewrite the card to add more context to the front to make it clearer what you're asking for. Do you always miss one or two pieces of the answer? If so, maybe split the card into multiple cards, each of which asks for one part of the answer. (Or add an additional card to direct your attention specifically towards what you struggle with, ala Nielsen.) Etc.
4) There's diminishing returns on card improvement. Time spent on perfecting an already OK card is time taken away from creating new cards to remember new information. If your goal is to remember as much as possible in a given time, spending time on perfecting already existing cards is trade-off not always worth making. (The quote: "a poem's never finished, only abandoned" comes to mind to highlight this.)
Using "only" North Korean propaganda videos and commercially available satellite images and published memoirs from NK defectors, they were able to located the building where NK is making their TELs.
> I agree with you that overly relying on flashcards will take away the intuition, which is critical in fields like mathematics.
Can't you just write a card that specifically asks you to give the intuition behind some concept?
E.g. "What's the intuitive interpretation of the gradient of a scalar field, \nabla \phi?" Answer: "\nabla \phi is a vector that points in the direction of greatest increase of \phi."
