Dual N-Back Test
Each turn a square lights up in the grid and a letter is spoken. Press A when the square is in the same place as N turns ago, and L when the letter is the same as N turns ago. Score well and the next session moves up a level.
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Press A when the square matches the one 2 turns back, L when the letter matches.
How to use the Dual N-Back Test
- Choose a mode and N. Start with Dual mode at N = 2 (or N = 1 if you are new to n-back).
- Press Start session. A square lights up and a letter is spoken every few seconds.
- Press A (Position) when the square is in the same place as N turns ago.
- Press L (Sound) when the letter is the same as N turns ago. You can press both, or neither.
- Review your score: with auto-level on, 80% or more takes you to N + 1 next time and below 50% takes you down a level.
How the n-back works, with an example
In a 2-back session you compare each item with the one from two turns earlier. Suppose the spoken letters are:
| Turn | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Letter | K | R | K | T | K | T | S |
| 2-back match? | – | – | Yes (K) | No | Yes (K) | Yes (T) | No |
Turns 1 and 2 can never match because there is nothing two turns back. The position stream works the same way with the square's place in the grid. In dual mode you track both at once, and a turn can be a match in one stream, both or neither.
Scoring and levels
- Hit: you pressed and it was a match. Miss: it was a match and you did not press. False alarm: you pressed and it was not a match.
- Score per stream = hits ÷ (hits + misses + false alarms). Correct non-presses are not counted, which stops a "press nothing" or "press everything" strategy from scoring well.
- Session score in dual mode = all hits ÷ all (hits + misses + false alarms) across both streams.
- Auto-level: 80% or more raises N for the next session; below 50% lowers it; anything in between repeats the level.
Each session has 20 + N trials. Matches are placed at random, about six per stream, with two turns matching in both streams in dual mode. Non-match turns are generated so they never accidentally repeat the item N back.
Training tips
- Start at 1-back or 2-back and let auto-level find your level. Struggling a little is the point.
- Rehearse the last N items silently ("K, R… R, K…") and update the list each turn.
- Use headphones and a quiet room. If speech is unclear, turn on on-screen letters.
- Several short sessions (around 15 to 20 minutes in total) are easier to keep up than one long marathon.
- Slower trial times (3.5 s) help when moving to a new level; faster times (2.0 s) add pressure once a level feels easy.
Frequently asked questions
What is the dual n-back task?
The n-back is a working memory task used in psychology research. You see or hear a stream of items and must say whether the current item matches the one from N steps earlier. The dual version runs two streams at once, a square position and a spoken letter, so you have to keep and update two sequences in mind. It was popularised by a 2008 study by Jaeggi and colleagues.
How does scoring work?
For each stream the test counts hits (you pressed on a match), misses (a match you did not press) and false alarms (you pressed when there was no match). The score for a stream is hits ÷ (hits + misses + false alarms), the method used by the open-source Brain Workshop program. Correctly ignoring a non-match is not counted, so pressing randomly cannot inflate your score.
When does the level change?
With auto-level on, a session score of 80% or higher raises N by one for the next session, and a score below 50% lowers it by one (never below 1). Between 50% and 79% you stay at the same level. In dual mode the session score combines both streams.
Does dual n-back increase IQ?
This is debated. Early studies reported gains in fluid intelligence, but later larger studies and meta-analyses found that training mostly improves performance on the n-back task itself and similar tasks, with small or unclear transfer to general intelligence. Treat it as a challenging working memory exercise rather than a proven IQ booster.
What is a good n-back level?
Most people find 2-back challenging at first and 3-back hard. With regular practice many people reach higher levels over a few weeks. Because the task is adaptive, the useful measure is your own level and accuracy over time, which the history chart shows.
Why can't I hear the letters?
Letters are spoken with your browser's built-in speech synthesis. Check that your volume is up and the tab is not muted. Some browsers have no voices installed or block speech until you interact with the page. If speech does not work, turn on Show letters on screen to play with visual letters instead.
Which letters are used?
The audio stream uses eight easily distinguished consonants, C, H, K, L, Q, R, S and T, and the position stream uses the eight outer squares of a 3 × 3 grid. The centre cell stays empty as a fixation point.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.