Digit span: the smallest useful memory test
You see a sequence once, briefly, then type it back. Forward span measures storage; reverse span adds manipulation while the material is held.
Typical capacity
Most adults handle about seven digits forward and two fewer in reverse. Capacity falls under fatigue and distraction more sharply than most other item types.
Why reverse is harder
Holding a sequence is storage. Reversing it requires operating on the contents while keeping them intact, which is the working part of working memory.
Chunking, and its limit
Grouping digits into pairs or familiar numbers helps. It also means span partly measures strategy, which is why it is one family among eight and not the whole paper.
Scored against age, education and area norms. Free certificate with a QR code anyone can verify.
Questions people ask
Can I replay the sequence?
No. It shows once for four seconds, which is what makes it a memory item.
Does writing it down count?
It defeats the item. The score is only meaningful if you hold it in mind.