OSpan: Math+Memory
Solve equations, remember letters
About this trainer
OSpan interleaves two jobs: you read a simple arithmetic equation and judge whether it is correct, then a single letter flashes that you must hold in mind. After a short run of these math-then-letter steps you recall the letters in the exact order they appeared. The point is to keep memorising while a distracting task keeps trying to push the letters out of your head.
What it develops
It loads working memory capacity, specifically the ability to hold a list of items while a second task competes for attention. That juggling of storage and processing at the same time is what the exercise stresses, along with resistance to interference.
History
It began in 1989 as a laboratory yardstick for working memory, not as a game, and became one of the most cited complex span tasks in cognitive psychology. In 2005 Unsworth, Heitz, Schrock and Engle released an automated, mouse-driven version that scored itself, which made it spread well beyond the original lab into hundreds of studies and, later, into brain-training apps.
Who created it — and when
Created by Marilyn Turner and Randall (Randy) Engle in 1989, then at the University of South Carolina, as a measure of working memory capacity. The widely used automated version was built by Nash Unsworth, Richard Heitz, Josef Schrock and Randall Engle in 2005.
How to train
Lock in the recall order first by silently rehearsing the growing letter string in a steady rhythm, then snap fully onto each equation and back. Do not let the math become an excuse to drop a letter, and do not slow the math down so much that you are really just memorising in the gaps. Push set length up only when your recall is reliable, not when it merely feels easy.
How long to practise
Short, focused blocks work best: around 10 to 15 minutes, a few times a week. Stop when accuracy starts sliding, because tired, sloppy reps train bad habits rather than capacity.
Evidence base
Evidence is strongest for exactly what you would expect, you get better at OSpan and at closely similar complex span tasks. As a measurement tool it reliably predicts fluid intelligence, but that is a correlation, not proof that drilling it raises your intelligence. When researchers actually trained people on complex span, Harrison and colleagues (2013) found gains transferred to other span tasks but not to fluid intelligence, and Redick and colleagues (2013) found no broad transfer at all, so treat claims about boosting IQ or general brainpower with caution.
Recommendations
Treat the equations as a genuine gatekeeper, answer each one honestly and quickly, rather than coasting through them to protect the letters.
FAQ
Is the arithmetic supposed to be hard?
No. The equations are deliberately easy. They exist to occupy and distract you, not to test your math, so the challenge lives in holding the letters while you process them.
Will this make me smarter overall?
Honestly, probably not in a broad sense. You will get clearly better at this task and similar memory-span tasks, but controlled studies have generally failed to show transfer to fluid intelligence or everyday thinking.
Why do I have to recall the letters in order?
Order recall is what makes it a true working memory test rather than simple recognition. Keeping the sequence intact under interference is the whole skill being measured and trained.
Variants
Close relatives swap the math for sentences you must judge as sensible (reading span) or for spatial symmetry judgements (symmetry span); the to-be-remembered items can be letters, digits or locations. Some versions adapt the set length to your performance, and the original lab task used words rather than single letters.