How to play
Dual N-Back Explained: Position and Sound Matches
By HumanCalc · Published · 3 min read
In Dual N-Back, you compare the current position and sound with the position and sound N turns earlier. The two comparisons are independent. Either can match, both can match or neither can match. You respond only to the matching channels.
HumanCalc presents a square on a 3×3 grid together with an audio cue. A round has 20 turns. Enable sound, learn the rule at N=1 if needed, and then try the worked N=2 example below.
What does N=2 mean?
N is the number of turns you look back. At N=2, compare turn 3 with turn 1, turn 4 with turn 2 and turn 5 with turn 3. You are not comparing with the immediately previous turn, and you are not matching anything that appeared anywhere in the sequence.
Follow this five-turn example
The position names and letters here are labels to make the example readable. In the game, you see the position and hear the audio cue. The first two turns at N=2 establish the history, so there is no match response yet. Notice that turn 5 is compared with turn 3, not turn 1, even though all three share a position.
| Turn | Position / sound | Compare with | Response |
|---|---|---|---|
| 1 | Top-left / C | No earlier turn | Wait |
| 2 | Center / H | No earlier turn | Wait |
| 3 | Top-left / K | Turn 1: top-left / C | Position only |
| 4 | Bottom-right / H | Turn 2: center / H | Sound only |
| 5 | Top-left / K | Turn 3: top-left / K | Position and Sound |
Use the two controls independently
A familiar cue is not enough: it must match at the correct distance. Avoid pressing a control just because the position or sound occurred recently. After each turn, move your comparison window forward by one.
- Position button or A key: the square matches the position N turns earlier.
- Sound button or L key: the audio cue matches N turns earlier.
- Both controls: both channels match.
- Neither control: neither channel matches.
Read the result at the same N
HumanCalc's accuracy includes correct match responses and correctly withheld responses, across both channels. Missing a match and pressing on a non-match both affect the result. Compare completed rounds at the same N before comparing different difficulty levels. At 80% accuracy or above, the result screen offers the next N. This is an in-game progression rule, not a clinical cutoff or a population percentile.
What can the score tell you?
A result tells you how you performed on this browser exercise. Research about transfer beyond working-memory tasks has produced differing findings. HumanCalc does not convert a level into IQ or diagnose memory ability.
