How to Measure Your Working Memory Capacity

Brain

Working memory is a system for temporarily storing and managing the information required to carry out complex cognitive tasks such as learning, reasoning, and comprehension. Working memory is involved in the selection, initiation, and termination of information-processing functions such as encoding, storing, and retrieving data.

Because there are several different components within working memory, there is no single measure of working memory capacity, says Dr. Fiona McPherson in her book Perfect Memory Training. Your capacity for numbers may well be quite different from your capacity for words, and different again from your capacity for visual images.

Digit span

This refers to the number of digits that you can correctly repeat back, in the correct order. A normal, unpractised person has a digit span of between four and eleven digits. You can increase your span slightly by practising the skill. You can increase it markedly by developing effective encoding strategies (and practising them). Basically it comes down to chunking: you need to practise seeing groups of digits as meaningful chunks.

To do this successfully you need some well-learned structure. Some people, for example, have used sport statistics, or addresses and dates. Others have found transforming digits into pounds and pence makes them more meaningful. Others find mathematical relationships memorable (e.g. 632 is memorable if you transform it into 6 ÷ 3 = 2).

Word span

How many words you can hold in working memory depends on

a) how long the words are, and
b) how much they sound the same (you can maintain more dissimilar words).

Your word span affects your ability to repeat back unfamiliar words, and therefore is critical to vocabulary acquisition. Your child’s quickness in mastering language, and your own ability to ‘pick up’ a foreign language, are both partly determined by this aspect of your working memory.

Reading span

Your ability to repeat back unfamiliar words is critical to your learning of new words, but your ability to understand complex sentences (your reading span) appears to be governed by a separate aspect of working memory.