The Corsi block-tapping test is a spatial memory task named after Philip Corsi, who developed it in the early 1970s. It is the spatial cousin of the digit span: instead of remembering numbers, you remember positions. It has become a standard tool in memory research and neuropsychology because it isolates spatial memory cleanly.
How it works
Nine blocks sit in a fixed, irregular scatter. Each round, some of them light up one at a time in a sequence, and your job is to tap them back in the same order. The sequence starts short and grows by one block each time you get it right, until you slip. The longest sequence you can repeat is your Corsi span.
In backward mode, you tap the blocks in reverse order, which is harder for the same reason backward digit span is harder: you have to hold the sequence and turn it around at once.
What counts as a good span
Most adults land on a Corsi span of about five. That means they can reliably repeat a sequence of five block taps. A span of six is above average, and seven is strong. As with digit span, the backward version usually comes out one shorter.
Spans vary with age, attention and how rested you are, so a single run is a snapshot rather than a verdict. Running it a few times gives a fairer picture.
Why the irregular layout matters
A neat grid lets you lean on patterns: you can remember “top row, then middle” as a shape rather than a set of positions. The Corsi board scatters the nine blocks irregularly on purpose, which removes that crutch and forces you to hold each position as a location in space. That is what makes it a truer test of spatial memory than a tidy grid game.
Spatial versus verbal memory
Running the Corsi test alongside a digit span test is a neat way to see the split between two kinds of short-term memory. Some people have a longer digit span than Corsi span, which suggests their verbal memory outruns their spatial memory. For others it is the reverse. Neither is better; they are just different channels, and most everyday tasks lean on both.
Try it yourself
The Corsi block-tapping test uses nine blocks in the classic irregular scatter, starts at two, and adds a block each round you get right, in forward or backward mode. Compare your Corsi span with your digit span to see which side of your memory runs longer.
