Memory
Number Memory
A number flashes on screen, then disappears. Type it back from memory. Each level adds a digit, starting at four — the classic digit span test, the most famous measure in memory research.
A number appears for a few seconds — memorise it, then type it back. Starts at 4 digits and grows one digit per level.
What this measures
Number memory measures your digit span: the longest string of digits you can hold in short-term memory and reproduce exactly. George Miller's 1956 paper 'The Magical Number Seven, Plus or Minus Two' made this the most cited finding in cognitive psychology. The verbal loop that stores digits refreshes by silent rehearsal, which is why longer numbers decay before you finish typing them — and why grouping digits works so well.
Where this shows up in real life
Phone numbers, PINs, prices, and short codes still land in everyday life. Digit span is also a classic lab probe of verbal short-term memory — the buffer you use when someone reads you a booking reference.
Score guide
| Rating | Score |
|---|---|
| Exceptional | 11+ digits |
| Excellent | 9–10 digits |
| Above average | 8 digits |
| Average | 6–7 digits |
| Below average | 5 or fewer digits |
How to improve
- Chunk digits in groups of 2–4, the way phone numbers are printed — 8-3-5-1-9-0-7 becomes 835·19·07.
- Say the chunks to yourself; the phonological loop holds sounds better than visual digit shapes.
- Attach meaning where you can: years, ages, door numbers. Meaningful chunks cost almost nothing to store.
- Type the digits you are sure of immediately — recall the tail while your hands empty the head of the string.
- Practise daily for a week and expect one to two digits of improvement from strategy alone.
Frequently asked questions
What is the average digit span?
The classic finding is seven plus or minus two: most adults recall between five and nine digits. Web-test averages sit near seven digits, with double-digit spans marking the top few percent.
How do memory athletes remember hundreds of digits?
They convert digits into pre-memorised images (a major system or PAO system) and place those images along a mental route. It is pure technique layered on ordinary memory hardware — the world record for spoken digits exceeds 500.
Does digit span relate to intelligence?
Digit span is one component of working memory, which correlates moderately with fluid intelligence. Backward digit span — reciting in reverse — correlates more strongly because it adds manipulation to storage.