People who are good at remembering large amounts of stuff, like multiple digits of pi or whatever, tend to have interesting mental techniques they use to improve their skills. A couple of these, chunking and back-chaining, work well with the memorization of sequences. If you take a long series of digits and break it up into chunks, such that each small chunk has what seems like some kind of internal relationship, then you can memorize each of these chunks relatively easily. The working memory of the average person can only contain something like seven items, but if you break something up into chunks then each of those chunks can be one of the seven or so items you hold in your head at a time. If you can memorize the chunks, and then memorize the connections between them, you’ve got it down.

The problem can often be the connection between the chunks, where you’re reciting something and one chunk is complete but you’re unsure what comes next. I find back-chaining useful in this instance, where you look, not just at how things go forward, but how they go backwards, and practice connecting each chunk not just with the next but with the one before it. I’m currently using this and skip counting to relearn my times-tables.

Some of you from my generation or earlier might remember learning times-tables by rote in primary school. These days the curriculum is a little more broad and perhaps in some ways shallower, so if somebody misses their times tables we don’t like to necessarily punish them and so there might not be the same emphasis. This is probably good, in some ways, but it looks like there might not be the same facility with basic arithmetic in the children of today than yesteryear. Anyway; I never learned my times tables properly, back then. If I recall correctly, the learning process involved chanting “seven times seven is forty nine; seven times eight is fifty six.” I could do that fine, but I hadn’t actually memorized most of them, and instead was just figuring it out as I went along, because usually the time it took to state the complete sentence was enough to get the relatively simple calculation done.

But skip counting is a little different. We all probably know what that is, or at least we can recognise it when the skip size is two. It’s as simple as going “two-four-six-eight-…” up to whatever number. But it’s a little more complicated to go “three-six-nine-twelve-…” or “…twenty-one, twenty-eight, thirty-five…” with the various larger numbers. I find that, when I practice skip-counting with bigger skip sizes, I naturally start chunking the sequence, such that “fifteen-eighteen-twenty one” forms one chunk and “twenty-four, twenty seven, thirty” forms another. Sometimes, though, the connection between chunks isn’t as strong as the internal structure of the chunks themselves, which is where back-chaining becomes useful, going down through the sequence, and sometimes forming alternate chunk regimes, so that there’s a different way of breaking up the sequence which creates an overlap between the existing chunks.

The task I’ve set myself is probably relatively unimportant, but I like to keep my brain busy and have a few mental projects to work on just as a form of exercise. The process of chunking, however, is less trivial, and can be used as a great way to categorise, organize and internalize large amounts of information for efficient retrieval. Most of us do it instinctively to some extent, otherwise we’d never be able to remember anything of any significant size, and so that’s part of why books have chapters and songs have verses. But becoming conscious of the technique and finding new ways to apply it can probably improve our abilities in mutliple areas.