Dual N-Back · Guides
Fluid intelligence and dual n-back: reading the 2008 study
Define fluid reasoning, examine the historical Jaeggi experiment and distinguish its test outcomes from claims about an iPhone app.
In this guide5
Define the outcome before discussing training
Fluid intelligence refers to reasoning about unfamiliar problems rather than recalling previously learned knowledge. Matrix-reasoning tests are one way researchers study it. A score on a reasoning test and a score on a dual n-back exercise are different outcomes.
What Jaeggi and colleagues reported in 2008
The study used adaptive dual n-back training and compared changes on matrix-reasoning tests with groups that did not train. Its authors reported larger gains in the trained groups. This was a result in a particular experiment, not a trial of the commercial iPhone app linked here.
Separate a hypothesis from an established mechanism
The authors discussed shared demands and brain networks as possible explanations for transfer. That does not show that an individual phone session strengthens a named brain circuit or improves everyday problem solving. A proposed explanation must be distinguished from what the study measured.
Read the later evidence as well
Later trials and reviews reached different conclusions about transfer. Soveri and colleagues’ 2017 meta-analysis distinguished transfer to other n-back tasks from broader cognitive outcomes. Improvement on a practised task cannot be treated as proof of a general intelligence increase.
Three questions for a training claim
Ask which outcome was tested, what comparison group was used and whether the findings concern this app or a research task. A study schedule describes its protocol; it is not an optimal weekly prescription for you. For your own practice, record task settings and results without translating them into IQ points.
Questions
Does the 2008 study validate this iPhone app?
No. It examined a research training task and particular outcome tests, not the commercial app linked on this page.
Does a higher n-back score establish a higher IQ?
No. A task score and an intelligence-test score are different outcomes. Evidence of transfer needs appropriate outcome measures and comparison groups.
Does the study prescribe an optimal weekly routine?
No. Its schedule describes an experimental protocol, not a proven optimum or a personal prescription.
Further reading
- Jaeggi, Buschkuehl, Jonides & Perrig (2008), Improving fluid intelligence with training on working memory, PNAS
- Redick et al. (2013), No evidence of intelligence improvement after working memory training, Journal of Experimental Psychology: General
- Melby-Lervåg & Hulme (2013), Is working memory training effective? A meta-analytic review, Developmental Psychology
- Au et al. (2015), Improving fluid intelligence with training on working memory: a meta-analysis, Psychonomic Bulletin & Review
- Melby-Lervåg, Redick & Hulme (2016), Working memory training does not improve performance on measures of intelligence or other far transfer, Perspectives on Psychological Science
- Soveri et al. (2017), Working memory training revisited: a multi-level meta-analysis of n-back training studies, Psychonomic Bulletin & Review
- Simons et al. (2016), Do “Brain-Training” Programs Work?, Psychological Science in the Public Interest
- Cepeda et al. (2006), Distributed practice in verbal recall tasks: a review and quantitative synthesis, Psychological Bulletin
- Cepeda et al. (2008), Spacing effects in learning: a temporal ridgeline of optimal retention, Psychological Science
Guides
How to play dual n-back: a clear first session
Understand position matches, sound matches and the meaning of N before your first dual n-back session.
Dual N-Back settings on iPhone: audio, feedback and levels
Understand audio, feedback, N-levels, progression locks and session length with an annotated screenshot of the Dual N-Back iPhone app.
Dual n-back scoring: formulas, examples and calculator
Understand hits, misses and false alarms in dual n-back. Compare scoring formulas with a worked example and an interactive calculator.
Does dual n-back training work? What the evidence actually says
An honest walk through the research on dual n-back: what improves, what does not, why the meta-analyses disagree, and how to train without fooling yourself.