I’ve recently been reading a German memory study from 1987 that compared the efficacy of two different approaches to memorizing numbers, both using a memory palace based on 30 major sites in Berlin. (For those who’d like to look it up, it’s called Mnemonic Training for the Acquisition of Skilled Digit Memory by Kliegl, Smith, and Hechhausen.)
They looked at two test subjects. One learned how to encode numbers based on the Major system. (They call it the “Figure” system.) And the other learned a system I’ve never heard of before: “History-Dates.” I’m curious if anyone here has heard of it or uses it.
It would be a fairly challenging system to acquire. The idea is that you would memorize an historical event associated with every year from 1000 to 1999. So, yes: 1,000 historical dates. For every grouping of three digits that you need to remember, you would imagine a “1” in front of it, to make a four-digit date. You would then store the corresponding historical event in your memory palace.
Here’s an example. Say you’re wanting to memorize pi in 3-digit chunks, ignoring the initial “3.” So you’d start with [3.]141592. You’d take “141,” add a leading “1” to it to get a four-digit year, and end up with 1141. You’d then take whatever event you’ve previously memorized that happened in 1141 and put that in the first location in your memory palace.
This technique seems highly creative. But I can’t imagine anyone embracing it, since it does require memorizing 1,000 historical events and can’t be easily adapted for image creation on the fly, as Major can. Since I’d never heard of it before, it’s also baffling to me that the researchers in this study considered it one of two main ways mnemonists remember long strings of numbers.