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In the neurosciences, memory span is the number of items, usually words or numbers, that a person can retain and recall. Where numbers are used it is also known as digit span, and the test is called digit repetition. It can be seen as a measure of working memory (or short-term memory, depending on the psychological framework used), although other factors such as attention and comprehension also contribute to the performance on this test.

In a typical test of memory span, a list of random numbers is read out at about the rate of one per second. The test begins with 2 to 3 numbers, increasing until the person commits errors. Recognisable patterns (for example 2, 4, 6, 8) should be avoided. At the end of a sequence, the person being tested is asked to recall the items in order. The average digit span for normal adults without error is five to seven.

Reverse repetition is more difficult and requires more processes besides immediate recall.

Individuals with larger memory spans can keep in mind more different stimuli, and this seems to give them an advantage for a wide variety of cognitive tasks. Memory span has been linked to performance on intelligence tests, reading skills, problem solving, and a variety of other cognitive tasks.

The World Record is 198 by former World Memory Champion Clemens Mayer. But people taking part in memory competitions achieve far higher results in this test anyway, because the mnemonic techniques they use skip the short-term memory and give direct access to the long-term memory. With the "journey method" and the "master-system" (to code digits into mental images), everyone can achieve a score of 40 or higher in the "memory span" test as described above.

• Epstein, O.; D. Perkin, J. Cookson, D.P. de Bono (2003). Clinical Examination. London: Mosby, 294. ISBN 0723432295.