In the spirit of conservation, I’m posing two questions as one.

It turns out that my use of the term “chunking” or “chunk” has been unintentionally imprecise. Thank you to Shaun for correcting me on this. I was using the term “chunk” to mean a sub-sequence within a larger sequence. So, at n-back 7 I break the overall sequence of seven into two sub-sequences of 4 and 3, or 5 and 2. Shaun pointed out that “chunking” really means identifying a meaningful sub-sequence to aid mnemonic memory and recall. So chicago is a chunk within the string of letters trhochicagopt.

OK. So that’s the first question out of the way. I’m not chunking, I’m “sub-sequencing,” which is, unfortunately, a much more clumsy and less handy term than chunking. But I’m sure we’ll better it.

So, rephrasing the remaining question: “To Sub-sequence or Not To Sub-sequence, that is the question.”

Rupert questioned the idea of rehearsal when I proposed it as part of a strategy for mastering n=5. Some might also question sub-sequencing, since it seems to undermine the development of working memory capacity. Will has pointed out that even with rehearsal and sub-sequencing the dual n-back test remains immensely challenging, and requires us to swap a whole bunch of stuff in and out of working memory quite quickly.

After the blog discussion with Shaun on Klingberg’s book (is it primarily focus or working memory we’re training beyond a certain point?), and after my session yesterday when I tried sub-sequencing n=10 with 6 & 4, I was thinking about this some more. It occurred to me that holding and swapping distinct sets of information in and out of working memory closely mirrors what we need to do when faced with demanding intellectual challenges in everyday life.

Rarely does a complex mental challenge require us to hold and manipulate just one set of data. Raw digit span capacity applies when transcribing a social security number, for instance, but when solving a multi-faceted problem we typically need to bring one or two parts of the problem into mind, hold them, query them, add another aspect, nudge things around, try an example, etc.

So, I would tend toward the conclusion that extending our single-sequence-recall limit as well as our combined-sub-sequence-recall limit both aid in enhancing out everyday intellectual skills.