Tuesday 7 April 2015

Digit span boosters?

It takes heroic amounts of practice to boost digit span, mostly by using chunking procedures (which themselves have to be learned) so as to improve the encoding of random number strings. There are better things to do in life. Digit span forwards is a measure of the length of acoustic memory trace that can be reported on before it fades. If you have the misfortune to number your digits in Welsh, then because the names of digits in that language are long, you will be able to fit in slightly fewer digits into the quickly fading memory trace. Digits backwards, of course, can be affected by the same variables, yet it is the additional  difficulty of that task which is particularly interesting, and not strictly relevant to these discussions about the increase in digits forwards since 1923.

However, it remains plausible that practising numbers in real life, like remembering telephone numbers, might have an impact on digit span forwards. Reader Richard Harper kindly sent me the Ngram for “combination locks”. Two can play at that game. Undaunted, I have immediately retaliated by adding in “telephone number” and “password” as comparable phrases, with the results shown below:



This shows that “combination lock” is, relatively speaking, nowhere. “Telephone number” became frequent in 1940 but after a steep rise began to fall by the millennium. Mobile phones allow names to be substituted for numbers, reducing memory load. The surprise is that “password” had been popular from the 1900s onwards, but the demanding, demeaning, insolent, insistent word booms after 1980, and becomes virally toxic just after 2000. Will no-one spare us from this pest? Mercifully, the agony is somewhat abating. Perhaps “iris” or that old standby “fingerprint” is responsible for saving us from the need to remember which unbreakable code we used to protect our bank accounts, payment systems, gas bills, electricity bills, mobile phone bills, google accounts, airline memberships, newspaper subscriptions, publisher’s login details, online supermarket accounts, amazon accounts, pension payment accounts, department store accounts, linkedin accounts, ISP accounts, anti-virus accounts, paypal, researchgate, ucl library accounts, science direct accounts, ebay accounts, squirrelmail, consumer organisations, and even places where you have once bought one random item, before sitting down to have a coffee near a wifi that will not let you in without a password, but will reject you once you give your email, because it is already taken by your former self, a slightly younger version who generated a password with insouciance, and never thought to write it down.

Personally, I doubt the demands of modernity have done much for digit span forwards. It is rarely a matter of life or death so the six or so generations since the rise of telephony will not confer any selective advantage. Gains may be due to general improvements in health and living standards. As regards passwords, I suppose it might be worth testing if alphanumeric recall had improved considerably between 1980 and 2000. However, I can think of a reason why recalling passwords will not have boosted any memory ability. A large section of the population, when asked to generate a password, obligingly choose “password”. Folk who resemble them in wisdom increase complexity by listing single digits in order of magnitude, no mean feat. Perhaps all these good people are very trusting, or cannot calculate probabilities, or simply have nothing to lose. A final word: digits forwards is only predictive when scores are low: high scores are less indicative of intellect. Rest easy.


  1. I have found the solution to passwords. I write them down encrypted in such a subtle way that nobody is likely to break them, but so that I find it easy to decrypt them. Naturally I shall not tell you how I do it.

  2. I await your best selling book!

  3. Interesting, and I am convinced with everything here as it applies to the general population. Still there is the odd thing where I had been doing Gregg Shorthand everyday for a number of years for university lectures and had a discussion about 'word span' in a shorthand forum. My sense and that of several others was that the regular use of shorthand over time increased word span -- when you are struggling to keep up with a fast-talking speaker and they pause and you write down the last twenty or sixty words. Given that shorthand has rapidly fallen out of use since the 1960's I would imagine people's word spans have been getting shorter and shorter, though the effect at the overall population level is almost certainly insignificant. I do not think of this as dysgenic, just lack of daily practice. (By the way - The movie In Cold Blood has Truman Capote boasting on several occasions of his ability to remember long conversations with a "95%" degree of accuracy. It might be entirely fictional or perhaps he also regularly practiced shorthand?) About the same time that tape recorders became inexpensive and common, adding machines and pocket calculators did as well and yet presumably math scores have not suffered since then. Of course all this relates to popular media reports on how Google is ruining our brains so I am highly skeptical as it applies to the general population. But still there seem to be some interesting puzzles involving special cases. Perhaps it comes down to the first sentence of your blog today, and that using shorthand daily amounts to ".. heroic amounts of practice.." and chunking procedures.

    1. Can't call the ref to mind, but a few people tried boosting digit recall over many months of practice, and eventually became able to code large strings of digits, but the skill did not transfer to other materials or memory tasks. A trick, not an expanded capacity. Still, like the idea of shorthand still being alive and well. My father had shorthand, but was defeated by "counter sunk hexagonal nuts".

  4. Encrypting passwords -- writing them in a personalized shorthand system works. Modified shorthand systems and encryption have some history together.