What does n-back mean?
The number n is the distance back in the sequence. In 1-back, compare the current letter with the previous one. In 2-back, compare it with the letter two steps earlier. In 3-back, look three steps back. Until enough signals have appeared, there is nothing to compare.
The task requires holding and updating information as each new item arrives. Working memory here means temporarily keeping information available and using it to carry out a task.
Three short examples
| Mode | Sequence | When to respond |
|---|---|---|
| 1-back | A → B → B | At the third signal: B matches the previous B. |
| 2-back | A → B → A | At the third: A matches A two steps earlier. |
| 3-back | A → B → C → A | At the fourth: A matches A three steps earlier. |
Now consider A → B → C → B in 3-back. The final B is familiar, but it appeared two steps earlier. The correct comparison is with A, so do not respond. Familiarity alone is not a match.
Learn the rule without a timer
- Write A–B–C–A–D–C.
- Compare the fourth letter with the first: A matches A.
- Compare the fifth with the second: D does not match B.
- Compare the sixth with the third: C matches C.
- Read the sequence again, deciding after each new signal.
This is a paper learning exercise. When the rule makes sense, open Cabe’s 3-Back page. Cabe uses letters compared three steps back. The 1-back and 2-back examples explain the principle; they are not a claim that every mode is included in the app.
Track misses and false responses
A miss happens when a target appears and you do not respond. A false response happens when you press without a valid match. Responding to every familiar letter creates false responses; never pressing avoids those but misses all targets.
Look at both types of errors. After a short series, identify whether the problem was keeping order, following the pace or mistaking a recent repetition for the correct match. Take a break when you notice yourself guessing.
What can training show?
A 2017 meta-analysis by Soveri and colleagues found the clearest transfer to other n-back tasks, with smaller effects on other abilities. This does not justify promising higher IQ or improvements in every kind of memory.
Treat the game as practice with a specific rule. To learn vocabulary, practise recalling words in context. For a different challenge, try spatial sequences. Track game performance separately from the everyday skill you care about.