N-back: Working memory
Does flash position match one from N steps back?
About this trainer
A stream of stimuli appears one at a time; you respond whenever the current one matches the one shown N steps back. As N climbs from 1 to 2 to 3, the load on working memory rises steeply.
What it develops
Working-memory capacity, updating (constantly swapping old items for new), and resistance to interference — the core "mental juggling" behind focus and reasoning.
History
The n-back procedure was introduced in 1958 as a laboratory measure of working memory. It became famous in 2008, when a study reported that training a harder "dual" version raised fluid intelligence — sparking the modern brain-training boom and a decade of debate.
Who created it — and when
The task is credited to Wayne Kirchner (1958). The influential training claim came from Susanne Jaeggi, Martin Buschkuehl and colleagues (2008).
How to train
Pick an N you can hold at about 80% accuracy and let it adapt — up when you are accurate, down when you slip. Train single-modality first; add the dual (position + sound) version only once single n-back feels controlled.
How long to practise
Training studies used roughly 15–20 minutes a day across several weeks. If you want any chance of transfer, that consistency — not the occasional long session — is the variable that mattered.
Evidence base
Be honest about the controversy. The 2008 result was exciting, but several well-controlled replications (e.g. Redick 2013) and meta-analyses found little or no transfer to fluid intelligence in healthy adults. What is solid: you reliably improve on n-back and closely related tasks. Treat "raises IQ" as unproven.
Recommendations
Train it for focus and updating, and for the satisfaction of beating your own N-level — not on a promise of a higher IQ. Keep it adaptive, and stop before fatigue wrecks your accuracy.
FAQ
Does n-back raise IQ?
The famous 2008 study said it could; later replications mostly did not confirm it. The safe claim: you get better at n-back and working-memory tasks.
Single or dual n-back?
Start single. Dual (position + audio) is harder and is the version used in the original training studies.
How long until I improve?
Improvement on the task itself usually shows within days; any broader transfer, if it happens at all, needs weeks of daily practice.
Variants
Single n-back (one stream); dual n-back (visual + auditory); and position, letter, colour or sound variants. Difficulty scales by raising N.