Digit Spandigit span test

Digit Span is a memory span test: digits appear one at a time and have to be repeated — in the same order, and then in reverse.

It is one of the oldest and best-known tests in psychology. It shows how much information a person can hold in mind at once and whether they can work with it.

In BB Gym, Digit Span is a trainer with three levels. Digits are shown on a card, and the answer is typed on a keypad. First you repeat the row forward, and at higher levels backward as well. Each part starts with a warm-up, and the result shows a score and a skill profile.

Where the test came from

As early as 1887 the British researcher Joseph Jacobs tested schoolchildren: he read them rows of digits and letters and watched how long a row they could repeat. He noticed that memory span grows with age.

Since then repeating digits has become a classic: it is part of many sets of memory and intelligence tests and is used in research all over the world.

How it works

First a short row is shown, for example three digits. If it is repeated correctly, the next one is one digit longer. Each length usually gets two tries, and a part ends when both fail.

Digits do not repeat within a row and do not stand next to their neighbours, like 4-5, so the row cannot be remembered as a run. Classically the digits are read aloud; in BB Gym they appear on screen.

Seven, plus or minus two

In 1956 the psychologist George Miller wrote the famous paper "The magical number seven, plus or minus two". He pointed out that people usually hold about seven items in short-term memory.

Later the researcher Nelson Cowan showed that the "pure" capacity, when you cannot group or rehearse, is closer to four. So adults manage seven digits partly thanks to tricks: grouping and silent rehearsal.

Forward and backward

Repeating a row in the same order is mainly about holding it. Repeating it backward means working with it: turning it around in your mind and giving it from the end.

In the working memory model of Alan Baddeley and Graham Hitch, a separate "executive" system is responsible for such work. That is why the backward span is usually one or two digits shorter than the forward one, and psychologists look at both measures separately.

What the trainer works on

The trainer loads working memory and attention: you have to focus on every digit and keep the row until the end of the answer.

Results improve with practice, because people get used to the task and find their own tricks. But to be honest, there is little evidence that such exercises improve memory in everyday life. A 2013 meta-analysis found that working memory training helps mostly on similar tasks, and a 2016 review reached a similar conclusion about brain training in general.

So it is best to treat Digit Span as an engaging memory warm-up and a way to track how sharp you are on different days.

How to play and what to watch for

Group digits in twos or threes, like a phone number: "582-917" is easier to remember than six separate digits.

Say the row to yourself in a steady rhythm. In the "Backward" part, first repeat the row forward in your head, then say it from the end.

There is no time limit for the answer, and a wrong digit can be erased until the row is complete.

Screen and lab: about norms

Published norms are tied to reading digits aloud, a particular pace and set of rows. On a screen everything is different, so compare results in BB Gym only between your own attempts.

Results in BB Gym are not a medical diagnosis or a neuropsychological assessment. If you are concerned about memory or attention, please see a specialist.

References

1. Jacobs J. (1887). Experiments on "prehension". Mind, 12(45), 75–79
2. Miller G. A. (1956). The magical number seven, plus or minus two. Psychological Review, 63(2), 81–97
3. Cowan N. (2001). The magical number 4 in short-term memory. Behavioral and Brain Sciences, 24(1), 87–114
4. Baddeley A. D., Hitch G. (1974). Working memory. Psychology of Learning and Motivation, 8, 47–89
5. Melby-Lervåg M., Hulme C. (2013). Is working memory training effective? A meta-analytic review. Developmental Psychology, 49(2), 270–291
6. Simons D. J. et al. (2016). Do "brain-training" programs work? Psychological Science in the Public Interest, 17(3), 103–186
7. Memory span — Wikipedia