Dual N-Back ("double n-back") is a working-memory task in which you have to track whether the current stimulus matches the one that appeared n steps earlier. In the "dual" version, two streams run at once — visual and auditory.
How the task works
You are shown a sequence of stimuli — for example, the position of a square on a grid and letters in headphones. You have to press when the position or the sound matches the one that was n positions back. The larger the n, the harder it is: you must constantly hold and update two sets of data at once. The task is used both to assess and to train working memory.
The debate about transfer to intelligence
The task became well known through the work of Jaeggi and colleagues (2008), which claimed that dual n-back training raises fluid intelligence (Gf). But as early as 2012, two studies failed to reproduce this effect: the improvement did not transfer to other tests. A 2017 meta-analysis found only a small transfer to other tasks and to Gf, and the effect turned out to be mostly specific to the training itself.
The honest conclusion
N-back training reliably improves performance on n-back itself and similar tasks ("near transfer"), but there is no convincing evidence of a lasting rise in general intelligence or of benefit in everyday life. For the brain, the more reliable options are the things proven to strengthen cognitive reserve: aerobic activity, sleep, learning and socializing.
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Calculators where Dual N-Back is used directly:
Frequently asked questions
Does dual n-back raise intelligence?
There is no convincing evidence of this. Training improves the n-back skill itself and closely related tasks, but transfer to fluid intelligence and everyday tasks is not confirmed in high-quality studies.
Is it worth training on n-back?
As an engaging game — why not. But if the goal is brain health, it is more reliable to invest in aerobic activity, sleep, learning new things and socializing: their benefit for cognition is better proven.