How this short term memory test works
A number appears on screen for a short time and then hides. Type it back. The first number has one digit, and every correct answer adds a digit to the next one. The test ends at your first wrong answer, and your score is the longest number you got right.
Psychologists call this measure digit span. It is the classic way to gauge short-term memory because it is simple, quick and easy to compare.
What digit span tells you
Most adults land on 7 to 8 digits. In 1956 George Miller described the limit as about seven items, plus or minus two. Later work suggests the underlying capacity is about four chunks, where a chunk is any group you treat as one unit. Seven digits read as two or three groups fit inside that limit, which is why most people hit the wall in roughly the same place.
Short-term, working and long-term memory
These three terms get mixed up. Here is the difference.
| Type | What it does | Example |
|---|---|---|
| Short-term memory | Holds a small amount of information for a few seconds | Keeping a phone number in your head while you dial |
| Working memory | Holds information while you do something with it | Adding two prices in your head |
| Long-term memory | Keeps information over the long run | Recalling what you did last weekend |
This test sits in the first row. You only have to hold the digits and give them back unchanged. If you want a task where you hold and act at once, try the working memory test. Digit span does not measure long-term memory at all.
Getting a fair reading
- Play two or three runs. The first is mostly a warm-up.
- Test when you are rested and free of distractions.
- For your raw span, read the digits one by one. Then play again while grouping them in threes and compare the two scores.
- Judge yourself by your average, not your single best run.
The full rating table is on the number memory test page, and the memory test page lists the other kinds of memory you can try.
A digit span score is a game result. It cannot diagnose memory loss or any other condition. If you are worried about your memory, see a doctor.