Digit Span

Digit span is the oldest and most widely used measure of short-term memory capacity.

Forward span is phonological loop storage. Backward span adds the manipulation component — you must reverse the sequence in mind.

Normal forward span is 7±2 (Miller's law). Backward span is typically 1-2 digits shorter.

The game stops after two consecutive failures at a given length.

Each test is constructed using Item Response Theory (IRT) and Classical Test Theory (CTT) to ensure reliable measurement of knowledge and ability across different difficulty levels.

Questions undergo rigorous review including difficulty calibration, discrimination analysis, and distractor effectiveness evaluation to maintain high assessment quality.

1. Digits will flash one at a time.
2. After the sequence ends, type them (forward or backward depending on mode).
3. Press Enter or tap Submit.
4. You stop after two consecutive mistakes.