Number Memory Test

It measures your digit span: the longest string of digits you can repeat back right after seeing it. Digit span is one of the most widely used tests of short-term memory, the small store that holds information for a few seconds while you use it [1].

In clinics the digits are usually read aloud, one per second. Here they appear on screen all at once for 1 seconds plus 0.6 seconds per digit, so your score is not the same as a clinical digit span score.

• The first number has 3 digits. Type it back and each right answer adds one digit.
• You get 2 tries at each length. When you miss every try at one length, the test ends.
• Your score is the longest number you typed back exactly right.

In a classic paper, George Miller pointed out that the limit of short-term memory is set by the number of chunks you hold, not the number of digits, and that people stretch it by grouping items into bigger chunks [2]. Reading 4-9-1-7 as "forty-nine, seventeen" is a chunking trick. It is fine to use one, but use the same approach each time so your scores stay comparable.

In a computerized study of 763 adults aged 18 to 65, forward digit span (repeating digits in the order heard, as on this page) did not change with age. Only backward span, repeating them in reverse, dropped slightly with age. People with more years of education scored slightly higher [1]. Practice with the task, tiredness and distraction can move it from day to day too. A single run is a snapshot; several runs on different days tell you more.

Other short-term memory tests on this site: sequence memory (the order of places on a grid) and n-back (holding things in mind while they keep changing).