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Visuospatial working memory

Corsi Block-Tapping — Forward & Reverse

Watch the 3×3 board light up a sequence, then tap the squares back in order (or in reverse). The original Corsi block-tapping task used to measure visuospatial short-term memory span.

What makes this one different

Most online Corsi tasks only do forward recall. Reverse Corsi is genuinely harder and exercises a different sub-process — researchers use the forward/reverse gap as a marker of working-memory flexibility.

Mode
Span 3
Phase Idle
Watch the highlighted squares, then tap them in the correct order.
Ad slot.

Span tracking

We adapt span automatically: 2 correct in a row → bump up; 1 miss → bump down.

Forward span (max today)
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Reverse span (max today)
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History

No sessions yet.

What problem does it solve?

Visuospatial short-term memory is the part of working memory that holds where things are — not just verbal lists. It's the same one you use to remember where you parked, navigate a familiar route, or remember the layout of icons on your desktop. The Corsi task (originally a 1971 wooden-block experiment by Philip Corsi) is the standard measure.

Adding a reverse-recall variant doubles the load: you have to hold the sequence and mentally reverse it before responding. Most adults drop 1–2 levels in reverse vs. forward; the gap is itself a signal.

Who is this for

How to interpret your results

Forward span of 5–7 is typical for adults. Top performers reach 8–9.

Reverse span is normally 1–2 lower than forward. A very large gap (4+) may indicate reduced working-memory flexibility, while a tiny gap (≤1) suggests strong manipulation ability.

Limitations

  • The original Corsi uses 9 irregularly-spaced blocks; we use a regular 3×3 grid. This slightly overestimates span (predictable positions help encoding).
  • Mouse vs. touch has different motor costs. Don't compare across devices.
  • This is recreational. Clinical Corsi tests have standardized board layouts.

FAQ

How long is each sequence flash?

600 ms per square with a 200 ms gap. If that's too fast, try the Digit Span tool where you control presentation rate.

Should I practice both modes?

Yes — alternating between them gives the cleanest training signal. Pure forward practice doesn't transfer fully to reverse.

How do I use Corsi Block-Tapping — Forward & Reverse step by step without mistakes?Follow the order given in the usage section: Reproduce growing sequences on a 3x3 grid. Tracks your forward and reverse visuospatial span separately — the asymmetry is the interesting signal. The step-by-step part matters less than the unit check that sits inside it. Confirm every unit matches the thing you are actually trying to measure before you press calculate - that single check catches more wrong answers than any other habit, and it costs about ten seconds.
What are the common mistakes when using Corsi Block-Tapping — Forward & Reverse?Most common mistakes come down to four habits: entering 20 when the field expects 0.2 because the field is a percentage; leaving a field blank and accepting the default without checking what it stands for; changing one input and reading a result that was calculated before the change; and quoting the output as an exact figure when the page describes it as a reference estimate. Press calculate again after any edit, and treat the number as a reference point rather than a final answer.
How do I read the result from Corsi Block-Tapping — Forward & Reverse?Read the final figure first, then come back to this section for the conditions behind it: Forward span of 5–7 is typical for adults. Top performers reach 8–9. Reverse span is normally 1–2 lower than forward. A very large gap (4+) may indicate reduced working-memory flexibility, while a tiny gap (≤1) suggests strong manipulation ability. Keep two things apart: the number itself, which comes from the values you typed, and the assumptions it depends on, which decide whether that number is meaningful. The page sets out what a higher or lower result means for your case, so check that direction as well as the magnitude.
Can I act on the Corsi Block-Tapping — Forward & Reverse result directly?Treat it as one reference sheet before you decide, rather than as the answer itself: The original Corsi uses 9 irregularly-spaced blocks; The output describes a magnitude under the conditions you entered. It does not include what it actually costs to act, what might change while you act, or how the other side behaves. Before you commit, compare the result against reality and note which assumptions do not hold where you are.