Corsi Block Test
Blocks light up in a sequence; you tap them back in the same order. Get it right and the sequence grows by one. Where you stop is your visual span — free, no account, about a minute in your browser.
Take the test
Watch the blocks light up, then tap them in the same order.
READY
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blocks in order
That is your visual span — how long a spatial sequence you can hold and play back. Much of the movement between runs is attention rather than capacity, so a single number wanders more than you would expect.
No sequence came back complete this time. The first one is only three blocks — worth another go.
- Longest correct
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- Rounds
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- Grid
- 3 × 3
Needs sight — the flashes are the only signal. Nothing is uploaded; your span stays in this tab.
That was a single run. In the app it becomes a short daily session, with a Focus Index to show for it.
Point your camera at the code — the App Store opens.
What the Corsi block test measures
Your visual-spatial span — visual short-term memory, in the plainer phrase: how long a sequence of positions you can hold intact long enough to reproduce it. Not how well you remember shapes, and not how fast you are — how much spatial order survives the few seconds between watching and tapping.
The design goes out of its way to keep language out. Nothing on the board has a name, so there is nothing to rehearse under your breath, and the sequence has to be held as a path rather than as a list. That is what separates this from digit span, and why the two can come out differently for the same person.
The ladder does the measuring. Rather than scoring one fixed length, the task keeps growing the sequence until you cannot follow it — so the result is the edge of your capacity rather than a percentage of some arbitrary target.
Where it comes from
- 1972
Corsi builds the spatial twin of digit span
Philip Corsi, working on his doctorate at McGill, needs a visual-spatial version of the familiar "repeat these digits" test. His answer is a board of nine blocks tapped in sequence — no words, no numbers, nothing that can be rehearsed under your breath.
- Then
Two memories, not one
The task earned its place because people can be good at one span and poor at the other. That dissociation is a large part of the evidence that verbal and visual-spatial working memory are separate systems rather than one general capacity.
- Today
A clinical fixture
Versions of the block-tapping task sit in neuropsychological batteries worldwide, and the original nine-block layout is still the standard. What varies is everything else: board arrangement, timing, how many failures end the run.
Reliability and validity: what is actually established
Two things about the block-tapping task are solid, one is not, and the difference is worth having straight before you read anything into a span.
The dissociation is established. People with a short block span and an ordinary digit span exist, and so do people with the reverse. That pattern is a large part of why visual-spatial and verbal working memory are modeled as separate stores rather than one pool, and it is the reason the task earned a place in neuropsychological batteries and has held it for more than fifty years.
Comparability between versions is not. A 1998 review by Berch, Krikorian and Huha found that almost every detail of administration differs from one laboratory to the next: how the blocks are arranged, how fast they are tapped, how many failures end the run, whether the score is the longest sequence or that length multiplied by the trials passed. Each of those choices moves the number, which is why published norms disagree with each other — and why a span produced by one procedure cannot be read against another, ours included.
Reliability sits in between. A span is one coarse number that moves in whole blocks, so a single run is a noisy estimate of anything; retested on another day, the same person routinely lands a block either side of where they were. That is a property of the measure rather than a fault in this page, and it is the whole reason the only comparison we offer is between your own runs.
How to read your result
One number, and it is deliberately blunt: the longest sequence that came back complete.
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Your span
The longest sequence you played back correctly, start to finish. Partial credit does not exist here: five of six taps right is a failed round, because a sequence you nearly have is a sequence you do not have.
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Rounds
How many sequences you were shown. A high span reached in few rounds means you were not slipping on the way up; the same span after several failures is a shakier number.
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Grid
The board it was measured on — 3×3, nine blocks, which is the layout the original test used and the ceiling on how long a sequence can get.
What this version cannot tell you
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A span is a coarse number
It moves in whole blocks, so there is nothing between 5 and 6. Two runs differing by one are not meaningfully different, and published figures for adults sit around five or six.
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Naming the blocks is cheating the task
Number the positions in your head and you turn a spatial test into a verbal one — a different memory system entirely. It will raise your span and stop measuring what the test is for.
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Screen and timing matter
The original used physical blocks tapped by an examiner at their own pace. A fixed on-screen cadence on a phone is not the same instrument, so values here do not map onto published norms.
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It is not a diagnosis
Block tapping is used clinically, always alongside other measures and interpreted by someone qualified. A short span on one browser run means you had a short span on one browser run.
Questions about the Corsi block test
What is a normal Corsi span?
Published figures for the Corsi block test put healthy adults around five or six blocks, which is close to the familiar digit-span range. Treat that as background rather than a target: span is a coarse measure that moves in whole steps, our timing is not the clinical timing, and a run on a phone is not a run in a clinic.
Why does a single wrong tap end the round?
Because in the Corsi block test a sequence you nearly reproduced is not a sequence you held. Partial credit would let a lucky first half inflate a span, and span is defined as the longest sequence you can play back in full. Two failures at the same length end the run — the first one may be a slip, the second is where you actually are.
Can I count the blocks in my head instead?
You can, and it works, and it stops the test from measuring what it is for. Naming positions moves the job into verbal memory, which is a separate system — the whole reason Corsi built a wordless task in the first place. If you catch yourself doing it, your span here is not a spatial one.
Why does this go up to nine when the app does not?
They are measuring different things. This page is a span test, so it keeps growing the sequence until you cannot follow it — up to the nine blocks the board holds. In the NEURA app, Corsi is a training drill on an adaptive difficulty curve, and the number you see there is a game score feeding your Focus Index, not a span. Nothing on either side contradicts the other; they simply are not the same quantity.
How does the Corsi block test differ from digit span?
They are the same idea in two different systems. Digit span is verbal: a list of numbers is read out and you say it back, so it can be rehearsed under your breath. Corsi is spatial: nothing on the board has a name, so the sequence has to be held as a path rather than as a list. Corsi built the block task in 1972 precisely to have a wordless twin of digit span, and the two spans can come out differently in the same person — which is the evidence that verbal and visual-spatial working memory are separate systems. Published figures for both land in a broadly similar range for adults, which is a reason to keep the two apart rather than to treat one as a stand-in for the other.
Do I need an account?
No. The Corsi block test runs entirely in your browser, nothing is submitted, and your span is shown to you and then gone when you close the tab.
One run is a snapshot. The trend is the point.
A span from one afternoon moves with how alert you happened to be. In NEURA the drill adapts to you and its result joins the rest of the catalog — 19 games — in a single Focus Index, so what you watch is your own line over weeks: the part no single page can show.
