Memory
Dual N-Back
A square flashes on a grid while a letter is spoken. Press A when the position matches the one from N steps back, L when the letter matches. The most demanding — and most debated — working memory exercise there is.
A square lights up while a letter appears. Press A (or the Position button) when the position matches 2 steps back, L (or Letter) when the letter matches. 22 trials.
What this measures
Dual n-back measures working memory updating: continuously holding two parallel streams (positions and letters), comparing each new item against the one N trials back, and discarding what is no longer needed. It became famous when a 2008 study by Jaeggi and colleagues reported fluid intelligence gains from training, launching a research storm and a loyal training community. The transfer claims remain contested, but the task's demand on executive attention is not — at n=3, virtually everyone's accuracy collapses, which is exactly the point.
Where this shows up in real life
Holding two updating streams (what was said and where it was) mirrors air-traffic, trading, and complex troubleshooting. Training here is demanding; treat it as a workout for working memory, not a guaranteed IQ boost.
Score guide
| Rating | Score |
|---|---|
| Exceptional | 90%+ accuracy (any n) |
| Excellent | 80–89% accuracy |
| Above average | 70–79% accuracy |
| Average | 55–69% accuracy |
| Below average | under 55% accuracy |
How to improve
- Don't rehearse verbally — let positions and sounds settle into an intuitive 'flow' and respond to felt matches.
- Master n=2 to 80%+ accuracy before attempting n=3; jumping levels early teaches guessing habits.
- Treat the two streams independently. Trying to bind position and letter into one object doubles your load.
- Sessions of 15–20 minutes are standard in the research protocols; more brings fatigue, not gains.
- Expect n=3 to feel impossible at first. Progress on this task is slow and real.
Frequently asked questions
Does dual n-back actually raise IQ?
The honest answer: contested. The original 2008 findings of fluid intelligence transfer have been both replicated and failed to replicate; meta-analyses suggest strong improvement on the trained task, with small or inconsistent far transfer. What is uncontroversial is that it heavily exercises working memory updating.
What level should I train at?
The standard protocol adapts: move up a level when you exceed roughly 80% accuracy, drop down below 50%. Most beginners live at n=2 for weeks — that is normal.
What do the A and L keys do?
A signals a position match (the square is where it was N trials ago); L signals a letter match. On a match of both, press both. On mobile, use the on-screen buttons.