Latest N-Back Brain Training Studies: Effective Sleep and Training Synergy

We know from an often skeptical press that many brain training apps do not work beyond practice effects specific to the games themselves. But it’s clear from the steady stream of peer-reviewed cognitive neuroscience research that some types of brain training are effective for increasing IQ and focus (ref). 


So what works? What brain training has so-called far-transfer to general cognitive abilities (as opposed to ‘narrow transfer’ to highly similar tasks to the game you train with)?


John Hopkins N-Back Study : Oct 2017


Have a look at this October 17th 2017 Johns Hopkins University press release about a study published that week on dual n-back training. The study was published in the Journal of Cognitive Enhancement and can be found here Johns Hopkins researchers suspected the problem wasn’t the idea of brain training that actually works, but the type of training exercise researchers chose to use. 


The training exercises Johns Hopkins compared are not the commercial products typically available and sold to consumers, but tools scientists rely on to test the brain’s working memory. Working memory is your ‘mental workspace’ – the amount of information you can focus on, update and process ‘online’ for problem solving, reasoning, planning, comprehending & decision-making. Working memory is a critical sub-factor of IQ, and is directly tested in full-scale IQ tests such as the WAIS-IV


There were three groups in the study: One group trained with the dual n-back, another group trained with another working memory exercise called the symmetry span task, and a third (control) group trained with a challenging verbal logic task that did not involve working memory.  Everyone took a round of cognitive tests, trained five days a week for 30 minutes, then returned to the lab for another round of tests – including brain EEG recordings – to see if anything about their brain or cognitive abilities had changed.


The researchers found that the group that practiced the dual n-back exercise showed a 30 percent improvement in their working memory. That was nearly double the gains made by the group working with the other working memory exercise. The dual n-back group also showed significant changes in brain activity in the prefrontal cortex, the critical region responsible for higher learning and IQ.



University of Tübingen Sleep + N-Back Study : Dec 2017/Jan 2018


Sleep has been known for a while to be important in consolidating memories and motor skills. It’s also a period where more neurogenesis (the birth of new brain cells in adulthood (ref).


In this latest Neurobiology of Learning and Memory publication, researchers at University of Tübingen wanted to know whether sleep might help synergistically with the working memory gains from n-back training demonstrated in the John Hopkins’ study (preprint here). Their research studied both adults and children. It compared working memory gains after only a short amount of n-back training (just 3 sessions) in two conditions: (1) where training was followed by a night’s sleep (training in the evening); (2) where training was followed by a day awake (training in the morning).


The data revealed the following:

  • Overnight sleep facilitates training-based improvements in working memory (maximum n-back performance)
  • Both adults and children profit from sleep in these ways.


The researchers conclude:

Overall these findings do not only indicate that working memory performance is subject to plastic changes but also that sleep is a brain state that can be exploited to enhance such changes.



if sleep follows the training of working memory, afterwards the brain is able to operate on longer event sequences, than after post-training wakefulness.


When to Train?


This latest study tells us when dual n-back training is optimal: In the late evening, 1-2 hours before a good night’s sleep! 


Johns Hopkins showed us that working memory could improve substantially (30% in their study) from n-back training. Most of those training in that study trained during the day, not just before sleep in late evening. So we would expect even greater IQ gains from training before sleep.



N-Back Meta-Studies – Bringing It All Together


This most recent study adds to the message the last 33 published, randomized, active-controlled dual n-back studies tell us: there are real training effects of DNB brain training on IQ (particularly working memory) – beyond placebo effects and just getting good at the n-back game itself through practice (review 1, review 2). There has been controversy concerning far transfer to fluid reasoning ability (also known as Gf) from dual n-back training, but this controversy does not cloud results showing far transfer to working memory (also known as Gwm) – another key subfactor of general intelligence (G), and a better predictor of many real life IQ-demanding outcomes such as academic success.


And this very recent study adds to the message of the multiple brain imaging studies (Ref 1, Ref 2, Ref 3) showing neuroplasticity change in the fronto-parietal network (FPN). This is the brain’s ‘control hub’ and is also called the ‘executive control network’. It sends out top ­down signals for current task goals and exerts control by flexibly biasing information flow across multiple large-­scale functional networks. The FPN is a key network underlying intelligent, goal directed action and learning.  



Conclusion from Research


In conclusion, dual n-back training works. It improves IQ, and it does so to a useful extent (e.g. 30% improvement in working memory). These benefits can be improved if the training is conducted in the late evening followed by a sleep. 


And another take-home for your training – keep it rewarding. We know from the cognitive neuroscience (ref), that only learning involving success and reward is beneficial. Ensure you choose a game mode in the apps that you can see progression in over the course of a week – ideally sleeping within 1-2 hours of training!).


Apps that Work


Our IQ Mindware apps ( i3 Mindware for abstract IQ training, HighIQPro for applied IQ training, i9 for brain cross-training) all implement the original Johns Hopkins n-back, and the lab-based n-back games reviewed in the scientific meta-studies referenced above. They are not slimmed down versions found in app stores.


i3 also augments this training with more advanced training options (gated n-back) for those who may be ready for accelerated evidence-based brain training programs.



I am a cognitive scientist specializing in health, resilience and performance (HRP) brain training interventions and self-quantification. I have a joint Ph.D in cognitive psychology and neuroscience from the Center of the Neural Basis of Cognition (Carnegie Mellon/Pittsburgh) and for a number of years was a researcher at Cambridge University.

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