The full rules in plain language — the two streams, the N-back match decision, and a worked example at N=2. Then try it with a guided tutorial.
Dual N-Back shows you two things every few seconds: a square lighting up somewhere in a 3×3 grid, and a letter spoken aloud. Your job is to signal whenever the current square, or the current letter, is the same as it was N turns ago. You track both streams at the same time — that's the "dual" — and press a separate response for each. As you get accurate, N grows.
Demo only. In the game you press A or L when the square or the letter matches the one N steps back.
This preview just plays the streams — the real exercise takes your responses and scores them.
Each turn, one of the 9 cells in a 3×3 grid lights up. There is exactly one lit cell per turn. You're remembering where it was.
At the same instant, a single letter is spoken (A, B, C, …). One letter per turn. You're remembering which letter it was.
The two streams are independent. On any given turn the position can match while the letter doesn't, or the other way around, or both, or neither.
At N = 2 you compare each turn with the one two turns earlier. Here is a short position sequence (top-left, centre, and so on):
| Turn | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| Position | top-left | centre | top-left | centre | bottom-right | centre |
| Compare with (2 back) | — | — | turn 1 | turn 2 | turn 3 | turn 4 |
| Match? | — | — | match | match | no | match |
The only thing that counts is the stimulus exactly N turns back. A square that appeared three or four turns ago, or one that simply "feels familiar", is not a match at N = 2.
One key (or on-screen button) for "the square matches N back".
A separate key for "the letter matches N back".
Do nothing. Most turns are non-matches — silence is the correct answer.
You don't pick N manually after the first session. Finish a block with high accuracy on both streams and N rises by one. Drop below the accuracy threshold and N falls back. The exercise self-tunes to sit just past what's comfortable, which is where the training effect is.
N is how many turns back you compare against. At N=2 you check whether the current square or letter matches the one from 2 turns ago; at N=3, 3 turns ago. "Dual" means you do it for a visual stream and an audio stream at once.
Only when the current stimulus matches the one exactly N turns back. Separate responses for the position match and the audio match. Most turns match nothing — do nothing. A missed match and a false press both lower accuracy.
N=2. It feels impossible for a few sessions, then clicks. Let the adaptive level move you up.
A few focused blocks a day, roughly 10–20 minutes total, beats one long grind. Consistency is what moves N.
No — play free with no signup. A free account adds progress, history and streaks; premium removes free-tier session limits.
No signup required
← Back to the Dual N-Back overview