How to play dual n-back
One position. One spoken letter. Two sequences to keep in mind. This guide walks through your first session, shows what a match looks like, and explains your results.
Your first session
The “n” in n-back tells you how far back to compare. Start with 1-back to learn the controls, then try 2-back when you are comfortable following both sequences. This app lets you choose any level from 1-back to 9-back.
- Choose a level and check your sound. Use the minus and plus buttons to change difficulty. Select “Test sound” to check the spoken letters. Headphones can help you hear clearly.
- Start and watch both sequences. After a three-second countdown, a square flashes in one of eight positions around the center of the grid while a letter plays. The center is a reference point, not a target.
- Compare with n rounds earlier. If the position matches, press the Position button or A. If the letter matches, press the Audio button or L. Respond to each sequence independently.
- Keep updating what you remember. Each new round moves the comparison forward by one. The first n rounds are a warmup: remember them, but do not score matches yet. At the end, review your overall score and the two channel scores.
The default session has 20 scored rounds at 2.5 seconds per round, plus the warmup. The square is visible for half a second, but you can respond throughout the full interval. In Settings, you can choose 20, 40, or 60 scored rounds and a pace from 1 to 5 seconds.
What counts as a 2-back match?
Compare the current round with exactly two rounds earlier. Comparing with the immediately previous round would be 1-back instead.
Audio: C → H → C → H
The third letter matches the first: both are C. The fourth matches the second: both are H. Press Audio for the third and fourth letters. The first two letters are the warmup, so there is nothing to compare them with yet.
Position: top left → bottom right → top left
The third square is in the same position as the first. Press Position. The letters might be completely different; a position match still counts.
If both the letter and the position match their own values from two rounds earlier, press both response buttons. If neither matches, make no response. A repeated letter such as C → H → H is not an audio match on the third round in 2-back.
Keyboard and touch controls
| Control | Action |
|---|---|
| A / Position | Mark a position match |
| L / Audio | Mark an audio match |
| Both response controls | Mark a match in both sequences |
| No response | Indicate that neither sequence matches |
| Space | Start, pause, or resume |
| Esc | Pause an active session |
On a phone or tablet, use the on-screen buttons. Press the same key or button again to toggle an answer off. You can change either answer until the round ends; only your final selections are scored. During a session, Space always pauses. Leaving the tab or switching to another window pauses the game too; resuming gives you a countdown and replays the interrupted round. Ending a paused session discards that session.
How dual n-back scores work here
This app uses balanced accuracy. Each sequence has two equally weighted parts: the proportion of matches you correctly identify and the proportion of non-matches you correctly leave alone. The overall score is the average of the position and audio scores.
A scoring example
In a 20-round session, each sequence has 6 matches and 14 non-matches. Catch 5 of the 6 matches and correctly leave 12 of the 14 non-matches alone: your score for that sequence is about 85%, the average of 83.3% and 85.7%.
Responding on every round or never responding produces 50%. Warmup rounds are excluded. Open “Round by round” after a session to see each round at a glance, along with matches caught and missed, false alarms, correct rejections, and interruptions. Compare results at the same level and pace; History lists both for every session.
Common questions
Is it free? Do I need an account?
It is free to play in your browser, with no signup or app installation. JavaScript and audio playback need to be enabled for the game. This guide works without JavaScript.
Where are my results saved?
Your settings and latest 30 completed sessions are saved in this browser on this device. They are not sent to a server or synced between devices. Clear them any time from History, or by clearing the site's browser data. Reloading does not restore an unfinished session.
When should I increase the difficulty?
First get comfortable tracking both sequences at your current level. When you want more of a challenge, increase the level by one or adjust the pace in Settings. Keep conditions consistent when comparing scores. After each session the app suggests a level: 80% or more suggests moving up one, below 60% suggests moving down one. The choice is yours.
What does my score measure?
It describes your performance on this task at the selected difficulty and pace. It is not an IQ score or a clinical assessment, and improvement in the game does not establish an improvement in everyday memory.