GoKawiilAbout three years ago, I memorized the first one hundred digits of pi. I did it on a lark, after reading Joshua Foer’s Moonwalking with Einstein. The book’s central claim is that nearly anyone can achieve seemingly super-human feats of memory with proper technique and deliberate practice. Intrigued, I put the some of the techniques to the test and found that they worked surprisingly well. But they did not just work. They converted the hard and shapeless problem of how to remember into a problem of discipline and methodology. Remembering became engineering.
The central insight behind most memory techniques is an observation: the human brain is not bad at memorization per se; it is only bad at memorizing specific kinds of information. For example, you can probably only hold 5-9 objects in short-term memory, but you can visualize your childhood home with relative clarity. And most adults have well-developed memories for certain topics, such as a car mechanic for car engines. In absolute bits of information, we can hold a lot in our minds, but we struggle when that information lacks meaning or context.
Memorization techniques harness this observation with a method called elaborative encoding. The basic idea is to associate hard-to-remember objects with easy-to-remember objects. Perhaps the most famous example of this technique is called the method of loci. In this technique, you place objects you want to remember in a visually familiar place called a memory palace. And then recall is just the act of “walking” through a memory palace in your mind and visualizing each object.
To memorize digits of pi, I used a more modern and advanced technique designed specifically for memorizing numbers, called a person-action-object (PAO) system. In a PAO, one associates each digit in the set { 00 , 01 , 02 , . . . , 99 } \{00, 01, 02, ..., 99\} {00,01,02,...,99} to a person doing an action to an object. Then any six-digit number one wishes to memorize is encoded as the person from the first two digits doing the action from the second two digits to the object in the third two digits. I’ll call this combined image representing six digits a “glpyh”. For example, in my memory palace for pi, I have the glpyh: Albert Einstein twirling a leotard. What number does this represent? Well, in my PAO, I have the following mappings:
50 50 5 0 is Albert Einstein smashing a clock
is Albert Einstein smashing a clock 28 28 2 8 is Anubis twirling a staff
is Anubis twirling a staff 84 84 8 4 is Fabio wrestling in a leotard
So in my PAO, Albert Einstein twirling a leotard is the number 502884 502884 502884. PAO systems are powerful because they automate the process of coming up with elaborative encodings. And since you have one hundred persons, actions, and objects, you have one million unique and ideally memorable glyphs.
That’s basically it. Conditional on already having a PAO system memorized, memorizing one hundred digits of pi is pretty easy. I think I did this in roughly an hour. I may be underestimating, but it was shockingly fast. I definitely did it in a single sitting. This is because one hundred digits is only seventeen glpyhs. These fit into a relatively small memory palace—in my case, in the apartment of an old friend.
Obviously, the harder task was memorizing my PAO, since that requires memorizing one hundred “base” glpyhs! In fact, probably the single most time-consuming task of memorizing pi was not even memorizing my PAO but simply building my PAO in a spreadsheet. This is because each person, action, and object should be memorable and unique. For example, my PAO contains both Keira Knightley ( 77 77 77) and Natalie Portman ( 22 22 22). If I were to decode a glpyh with one of them too quickly, I might confuse the two. But I would not confuse them with Darth Vader ( 17 17 17) or Serena Williams ( 06 06 06). So each set of persons, actions, and objects should be maximally dispersed. (If I could build my PAO again, I would not include both actresses.) Memorizing my PAO took a bit of time, but I just used Anki cards on my subway commute. I committed to the bit because I figured having a system for memorizing numbers would be useful long term. (It’s moderately useful.)
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