Person-Action vs. Person-Action-Object vs. 3-Digit Systems

When I was deciding on what kind of memory system to use, I made a chart to compare the efficiency of different systems.

The comparison was between:

  • a 2-digit person-action (PA) system
  • a 2-digit person-action-object (PAO) system
  • a 3-digit system where three images are placed in each locus, which could be PAO or arbitrary

I’m not claiming that one system is necessarily better than another; I’m only sharing a bit of the research that I did before I chose a three digit system. 🙂

Here is the chart:

Comparison of memory systems

By the 25th locus, the three digit system can store 225 digits in 75 images compared to 100 digits in 50 images (PA) or 150 digits in 75 images (2-digit PAO).

What do you think?  Does the difference lead to a boost in performance?  Is there an even more efficient system than the ones listed above?

In the end, one of the reasons I went with Ben Pridmore’s system because it’s incredibly efficient for binary numbers.  By the 25th locus, it can encode 750 binary digits, using the same images as for the 3-digit decimal system and cards.

Update: read about a 4-digit system with 10,000 images.


  • I’m seriously considering going with a 3rd-level major system (1100 images). One of my main motivations is work (phone numbers which are chunked in a 3-3-2-2 pattern) and historical dates. Johannes Mallow mentioned that it is much easier to work with historical dates with a 3rd level system. I plan to go with a straight 3 digit= 1 image, not a PA or PAO system.

  • I think it is a good idea. For historical dates, Ben told me he uses something like this: 3-digit images for dates beginning with 1, and the hearts images (cards) for dates beginning with 2.

    Another competitor told me she uses the 3-digit images for dates, but only memorizes dates beginning with 1.

    I’m wondering if it would be too slow to separate the two sets of dates by placing them in two locations. E.g., 1000s could go in a sports stadium and 2000s could go inside a house — or somewhere that looks completely different.

  • How is your study of the Ben System coming? Some seasoned memory competitors have described giving up attempts to move to a 3rd level system. And if you don’t plan on competing at at least the national level, is it worth the effort?

  • Everything is going slowly at the moment. Work is very busy and I’m traveling a lot. I’m very happy with the system though.

    At the moment, I don’t know if I’ll be ready for the USA Memory Championships in March, but I’ll try to be there either way. I’m definitely planning on entering some international competitions later in 2011. It’s the only way to get the Grand Master of Memory title…

  • This was posted by someone on Florian Delle’s

    “This is a quote from Ed’s book (Remember Remember) published last year:

    ‘For the record, I once wasted a summer creating a thousand digit system with such a subject-verb-object system…… I soon dumped this unwieldy system- too much work. It also seems as though a 100-word vocabulary is much quicker perceived and more easily manipulated, even if champion memorizers like Ben Pridmore use noun-only versions of the thousand-item system to superb effect.’ “

  • Interesting — for some reason, I was thinking that Ed Cooke was using a 3-digit PAO system. I thought I had read it in Joshua Foer’s article in The Mind Sport of Memory 2008 Yearbook, but I just went back to look at it, and Foer describes Cooke using a 2-digit PAO system.

  • I use 3-digit system (000-999) and have another images for 00-99. These images are all objects.
    Now i’ll do person-images for 00-99 like Dominic System. And will try to use PAO(2-2-3=7 digits at time)
    I think using person+actions+objects is more interesting than object+object+object. But with 3-digit system you can remember more than PAO

  • Anyone use person action object sound byte? Came up with the last just recently.

    Ie Darth Vader slashing a teddy bear in half with a light saber saying “now, I am the master”. It really works! 2×4=8 is not bad for one image set.

  • Saddens me to see this discussion die. Anyone still out there? Is there a chat room or some place you memory athletes frequent? Dying to share ideas and brainstorm the next great thing…

  • Hi Rob,

    The main discussions take place in the memory forum here: