For some reason, I love memory palaces. Homes I have lived, places I went to on vacation, stores I visited, I turn a lot into memory palaces. Most of all I love creating them, as in creating from scratch. Various subjects have palaces build to be visually recognizable as a place for that subject. That helps retain a lot of factual information, as rather than having notes on paper, I have notes in my head. For most I do have an Excel page listing the loci, the images and the information just in case, but I mostly use a string of techniques that help contain the information way longer.
First of all is senses. I want every image to contain multiple senses. Sounds, smells, tastes, I need the images to involve me in more than one sense.
Second is a recovery moment. This is more time consuming at first. I start with walking through the palace twice on the day I create it, then another time the day after. Then I skip two days and then walk through it again. I skip 4 days next and after than I skip 7 days. I then do it exactly one month after. I have an excel sheet that tells me when things are due, and I set the dates in my phone calendar inbetween the two recalls on the first day. That both gives me a few minutes between the recalls, and I won’t forget to do a recall later on. After that month break, I want to check up on a palace once every three to twelve months (depending on the urgency to know the things). This is where an excel script helps me, it shows me when something is threatening to get overdue.
The recalls are done as fast as possible inbetween tasks of daily life. Moments like walking to the grocery store, a quiet moment at work, waiting at a traffic light, taking a shower. In order to pass the recall I need to know the image I placed, and the information it represents. Most of these recalls take about two minutes.
Aside from taht there is another technique I use, which helps me improve retention of more abstract concepts (like philosphical constructs) and chains of events (like the chernobyl disaster). I argue it, or I explain it in a simple way. I think of reasons why it is different, and then debunk them using the knowledge I have gathered. I argue it with myself, and I teach it to myself, but both are like a preparation for when I have to do it with someone else.
An example of an argument. I could think of a set of conditions that have to be met for the earth to be flat. Which can be observational in nature (we can see endlessly into the distance), or have to be measured (If I place a laser 1m above the ground and shine it straight east, parallel to the ground, It should pass though a hole put 1m above the ground, straight east from the laser, but a few kilometers away, the laser should pass right through the hole), but usually I stick to logic (if the earth is flat, why do methods made for a spherical earth work as well as they do?). Yet arguments like “everything else we see in space is ball-shaped” is not a valid argument, as the prescence of something is not always a reason to rule out the prescence of something else. It has to actually explain why the condition I set is false or can’t be true.
As for the teaching, I usually try to turn it into a story that I can tell my oldest daughter to help her understand. I named Chernobyl, to remember what happened there I have a story in my head, told in a way where events cleanly lead to other events, rather than the chaos it actually was. It is still the same story, but some things are left out. In that story there will be things that need further explaination for an 8-year old, from what radioactivity is to how the movement of the control rods moved the neutron flux to a more concentrated part of the reactor. This forces me to dig deeper in understanding, rather than knowing.
Understanding is a big part. Just play the why-game with yourself from time to time, it helps a lot. I once had a student ask me why we need to understand in order to know, as he passed many tests by just reciting the information he had to learn. So I gave him a physics question, a simple “If I let a ball fall straight to the ground, is the impact with the ground smaller, greater or equal compared to if I throw the ball horizontally away from myself? What if I put the ball in a canon and blast it into the distance?” That is a question that is often used in schools, but he couldn’t prove either point with equations. I asked who could, and someone got up. I let him write on the board and he actually got pretty close to a solid explaination for why the impact of all is mathematically the same. I then moved to my point, if you understand how something works, it is easier to recall why it works. If you know why it works, it is easier to remember how it works. And if you know how it works, you know what the story is. No matter if you are right or wrong, the deeper understanding allows you to retain information way longer than just knowing the information will allow.