Working Memory
A digit span test: read a sequence, repeat it back, one digit longer each round. Mean forward span is about 7 digits with an SD of 1.5.
Digits appear one at a time, starting with 3. Type them back in order. Each round adds one digit; two misses at the same length ends it. Most adults land near 7.
Play until two misses at one length to see your span.
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About this test
The module shows a sequence of digits, hides it, and asks you to type it back. Each success adds a digit; the longest sequence you get right is your digit span. The comparison is a normal curve with mean 7 and SD 1.5, after Miller (1956) and Cowan's 2010 review.
Seven, plus or minus two, is still a fair summary for digits. A span of 9 is better than about 91% of people; 5 is worse than about 91%. Cowan argues the true capacity for unrelated chunks is nearer 4; digits do better because they are easy to rehearse and group.
What is a normal digit span?
About 7 digits forward for adults, SD 1.5, so most people fall between 5 and 9. Backward span is usually about 2 shorter. It declines slowly with age: a typical 70-year-old is roughly one digit below a 25-year-old.
Is a digit span of 10 good?
Yes, about the 98th percentile on the module's curve (z = 2). Trained mnemonists go far beyond it by chunking: the subject in Ericsson, Chase and Faloon (1980) reached 79 digits after about 230 hours of practice, with no change in his span for letters.
What is working memory?
The small amount of information you can hold and manipulate for a few seconds: a phone number while you dial it, the start of a sentence while you read the end. It is distinct from long-term memory and correlates moderately with reasoning tests. Digit span is its simplest measure.
Percentiles above come from the same parameters the Working Memory module uses. See the methodology for how they are calculated.