Spatial Span (Backward)
Reproduce sequence in reverse
About this trainer
A grid of pads lights up one after another, and your job is to repeat the sequence by tapping the pads in reverse order — last one first, back to the start. Because you have to hold the path in mind and run it backwards, it leans harder on working memory than simply echoing the order you saw.
What it develops
It trains visuospatial working memory: holding a sequence of locations in mind and mentally manipulating it rather than just storing it. The reversal step also pulls in attention and executive control, since you have to keep the whole path active while rebuilding it in the opposite direction.
History
It grows out of the spatial-span tradition that began with the Corsi block-tapping task in clinical neuropsychology, where tapping cubes in order became a standard way to gauge spatial memory. The backward version followed the same logic as backward digit span — reverse the recall to load memory more heavily — and reversed spatial span is now offered in test batteries like the Wechsler Memory Scale and Cambridge Cognition's Spatial Span.
Who created it — and when
There is no single inventor of the backward spatial span. The forward task — the Corsi block-tapping test — was developed by Philip Corsi in his 1972 doctoral work under Brenda Milner at McGill, building on her earlier reports around 1971; the backward variant is a later adaptation by the wider research community, and a reversed Spatial Span subtest was added to the Wechsler Memory Scale (WMS-III) in 1997.
How to train
Don't try to memorise raw dots — turn the sequence into a shape or a path your eye can trace, then mentally walk that path backwards. Subvocalising or pointing along the route as it appears helps; chunk longer sequences into two or three smaller segments and reverse each. Push the length up only when you're clearing a level comfortably, and slow down to cut careless taps rather than racing.
How long to practise
Short, frequent sessions beat marathons: five to ten minutes a day, a handful of days a week, is plenty. Working memory tasks fatigue quickly, so stop when accuracy starts sliding rather than grinding on.
Evidence base
What's solid is narrow and unsurprising — practise this and you get better at this, improving your span on backward spatial tasks and similar ones. The bigger claims are where it falls apart: large meta-analyses (Melby-Lervåg and colleagues, 2016) found that working-memory training produces task-specific gains that do not generalise to intelligence or everyday cognition, so promises that it raises IQ, boosts general 'brain power', or wards off cognitive decline are not supported. Treat it as a focused workout for a specific skill, not a shortcut to being smarter.
Recommendations
Chase clean reversals at a length you can actually hold, and bump the difficulty up only once that length feels easy.
FAQ
Why is the backward version harder than the forward one?
Repeating a path forward mostly tests storage, but reversing it forces you to hold the whole sequence active and rebuild it in the opposite direction, which adds an extra manipulation step on top of memory.
Will this make me smarter or raise my IQ?
No. The evidence shows you get better at the task itself and close relatives, but those gains don't carry over to intelligence or real-world thinking, so it's best seen as targeted practice, not a brain upgrade.
How is this different from backward digit span?
Same idea, different material: digit span reverses a string of numbers and leans on verbal memory, while spatial span reverses a sequence of locations and leans on visuospatial memory.
Variants
Forward spatial span (repeat in the same order) is the easier baseline; the classic physical form is the Corsi block-tapping test with nine cubes. Variants tweak grid size, sequence speed, and how long the path is, and verbal cousins like backward digit span apply the same reverse-recall idea to numbers instead of locations.