How To Optimize Your Dual N-back Training

The question ‘What are the best strategies for increasing my dual n-back level?’ should be reframed as ‘What are the best strategies for increasing my working memory capacity and for improving my overall cognitive functioning?’

Before we tackle this question directly let us review some of the science.

KEY BACKGROUND THEORY

Working memory definition: Our mental workspace

The dual n-back trains train your brain’s working memory circuitry.

Working memory can be defined as a brain system that helps us keep information in mind while using that information to complete a task (e.g. planned or strategic action, comprehending,  problem solving, decision-making). This can involve actively inhibiting distracting information.

A useful metaphor for working memory is the ‘mental workspace’:

“a flexible, capacity limited, mental workspace used to store and process information in the service of on-going cognition”  (Morrison & Chein, 2010)

 

working memory mental workspace

Working memory: our mental workspace

Working memory has two separate short term memory stores for verbal and visual-spatial information. Both are active in dual n-back training.

There is also a ‘super-system’ called the ‘Central Executive’ or ‘attention control system’. This controls the flow of information into these two short term stores, and inhibits irrelevant information in order to focus on and remember information that helps with our goals and current tasks. This is the system that keeps updating items and ignores distracting information when you train with the dual n-back.

Working Memory Capacity

People differ in their working memory capacity. Working memory capacity is the size of your mental workspace – the quantity or number of ‘chunks’ of information you can hold in mind at a given time to apply to a task.

A person’s n-back level is generally a good measure of their working memory capacity. This is why the n-back is the gold-standard measure in cognitive neuroscience for working memory capacity.

n-back working memory capacity

N-back level can be used as a measure of WM capacity

 

An information processing bottleneck

Since working memory makes information available for more advanced cognitive processing, working memory capacity is a main limiting factor for all higher-order cognitive functions. It is like your computer’s RAM capacity. In general terms, the larger your ‘mental workspace’, the greater your processing power – and thus the greater chance academic and professional achievement. An example of this relationship is shown below.

working memory academic achievement

 

Effective working memory training:
Dual n-back training

The aim of all working memory brain training programs is to expand working memory capacity and improve attentional control. The most widely studied and well-established working memory training exercise is the dual n-back.

The n-back game requires you view a continuous stream of items (e.g., letters) and decide whether each item matches the stimulus presented n stimuli back. In Dual N-back training, two information streams in different modalities (e.g. audio and visual) are presented simultaneously and item matches have to be detected for both types of information. This dual task requires constantly updating items in both the visual short term story and the verbal short term stores of working memory.

dual n-back game

The dual n-back game

Dual N-Back: Working memory training to increase IQ

How is working memory and IQ (general intelligence) related? How does working memory training transfer to gains in intelligence? The answer is interference control – the ability to filter out distracting information while engaging in some cognitive task, using your attentional focus.

Studies by Burgess, Gray, and my grad-school colleague Tod Braver (article 1, article 2) provide brain imaging evidence of a large overlap of IQ and working memory brain mechanisms when there is need for interference control on a task – but not otherwise. Brain regions common to fluid intelligence and working memory became more active when there is a need to filter out distractions. Interference control is a so-called ‘executive function’ – the ability to use focused attention to filter out distracting information or suppress irrelevant habits or responses, when faced with cognitive challenges.

Dual N-Back Pro dual n-back trainingunlike standard dual n-back training – has built in interference requiring continual interference control to perform the task. You may have experienced interference in the standard dual n-back when the sequence of stimuli repeats itself before the target is presented. This creates confusion where you have to ‘repeat yourself’ to keep the series of items in memory. In standard dual n-back this happens randomly. I have built it in as a central feature for working memory training. Our data suggests this results in significantly better IQ gains.

PRACTICE : WHAT STRATEGIES?

We have now reviewed the necessary background information to answer the main question of this article. What are the best strategies for optimizing your dual n-back training with DNB Pro?

A critical distinction

The first point that needs to be absorbed is that strategies that increase your n-back level do not necessarily result in an increase in your working memory capacity. It is working memory capacity and ‘executive control’ gains that you want from your n-back training – not just a high n-back level per se. We will see below that some training strategies that can be adopted artificially inflate n-back levels while not helping your working memory capacity at all.

4 different training strategies that improve n-back level: Only 1 improves working memory capacity

There are four types of strategy training that are often used with dual n-back training. They can all improve n-back level performance. But only the first – rehearsal – is useful for expanding working memory capacity.

I. Rehearsal

We can improve our n-back level on the dual n-back game through using a strategy called rehearsal. For the audio stimuli, you can use your inner voice (‘sub-vocalization’) to rapidly repeat the string of letters for a particular n-back level to keep them in your mental workspace. The letters may even be said aloud. With this strategy you need to update the list one item at a time as new items are presented.  For the visuo-spatial stimuli, you ‘rehearse’ a location-by-location scanning of where the squares have just appeared. This may involve imagining the locations or actually moving the eyes.  Both the sub-vocalisation and scanning are rehearsal strategies, and they can be done simultaneously.

rehearsal strategy dual n-back

Rehearsal strategy – dual n-back

The rehearsal strategy is recommended as the strategy of choice for your  n-back training. Rehearsal training can transfer to other working memory tasks and increase memory for types of information not directly trained in the dual n-back game. There is evidence  that training with a rehearsal strategy benefits mental arithmetic and the ability to follow instructions and studies have shown that rehearsal strategy training can improve everyday memory.

II. Chunking

Sometimes during the dual n-back game, a letter or location may be repeated one two or even three times. When this happens it is easier to play the game because with only one ‘place holder’ there is less information to encode to do the task. Or at other times, there may be a meaningful string of letters that forms a word or acronym, or a sequence of locations that forms a memorable shape. When items can be grouped together like this, easing the burden on our working memory system, this is called ‘chunking’. Chunking can benefit from practice and it is widely used in n-back training to increase n-back levels.

chunking stategy dual n-back

Chunking strategy – dual n-back

While chunking is useful in everyday life to help us encode information efficiently, it is counter-productive for training to expand the capacity of working memory training. It’s as bad as using momentum to do sit-ups when you should be doing sustained crunches! It is actually a way of compensating for limitations of working memory capacity to increase your n-back performance. It’s possible to have no change in your brain’s actual working memory capacity (it’s ‘RAM power’) while effectively using a chunking strategy to increase your n-back level a few notches, giving the false impression of neuroplasticity changes in your working memory circuitry.

game window speed.png

 DNB Pro n-back training help to minimize this strategy when you switch on the ‘Turbo’ option, increasing the speed and breaking the rhythm of the information flow. This increases cognitive load and reduces the ability to chunk the information.

DNB Pro n-back training even more substantially reduces chunking by using stimuli that cannot easily be ‘chunked’ in meaningful ways – abstract ‘spherical harmonics’ in random locations.

III. Attention Hopping

As you get more experienced with standard dual n-back it is possible to strategically direct your attention in ‘hops’ or ‘jumps’ to useful strings of letters or square locations in order to maintain or go up an n-back level.  Using this strategy, you are not updating the letters or locations in your working memory item by item but are ‘counting through’ a particular string of length N and then refreshing it from the start again for the next string, missing possible matches in between.

Attention jumping-hopping strategy dual n-back

Attention hopping strategy – dual n-back

This strategy can work fairly well if you are playing an n-back game that has a low accuracy setting (e.g. Brain Workshop standard setting). Lower accuracy settings are chosen for n-back games on the market because they result in an easier, confidence building progression with n-back levels – but at a serious cost. Attention hopping, like chunking, is a compensation strategy for a working memory capacity that is not able to process a given n-back level. As with chunking, attention hopping strategies give the illusion of brain training gains (with increasing n-back levels) without in fact expanding working memory capacity.

Dual N-Back Pro minimizes attention jumping by having a higher accuracy setting built in, requiring that you update your mental workspace item by item, and not string by string.

IV. Playing the Odds

As a rule there is a general trade-off between accuracy and complexity. Under pressure, as the n-back task increases in complexity with a higher n level, there is a drop in precision. Deploying the ‘playing the odds’ strategy involves sacrificing accuracy to gain a higher n-back level by ‘guestimating’ locations or letters.  

As with chunking and attention hopping, playing the odds is a compensation-strategy when working memory is overloaded. It eases pressure on our working memory workspace, when what we want is the opposite: putting it under more pressure, like resistance training.

Development of Intuition

While doing the n-back, intuition can mean a number of things. A sense of intuition can result when you become well-practiced in something and you no longer need to apply a rule or strategy in a deliberate way. If you’ve been practicing ‘playing the odds’ this can begin to feel ‘intuitive’. That’s not such a good thing, and may be difficult to unlearn. The same goes for attention-hopping and chunking. However, practicing the rehearsal strategy over time may result in it feeling less deliberate and more spontaneous (more intuitive), and that can be a good thing since you can now focus on optimizing your n-back performance in more subtle ways – for example, tweaking the way you focus when there is more interference and relax more when there is less interference.

If you get underway in your n-back training with an effective, intuitive approach, stick with it provided the conditions listed in the next section for ‘core working memory training’ are met. As a general rule, I suggest that you combine rehearsal training with ‘untrained’ intuition for your DNB Pro n-back training to be most efficient. If you feel like you are chunking, attention-jumping, or playing the odds, focus on rehearsal. Otherwise, see how far intuition takes you.

Train core working memory

Core working memory training targets the Central Executive of your working memory system. This is ‘central command’ where attentional control regulates the flow of information in your mental workspace. It is where you filter, update and monitor the information from both audio and visuo-spatial items in the dual n-back game.

Core working memory training deliberately ‘stresses’ your brain’s information processing capacity with high ‘cognitive load’. Training is relatively energy-consuming and effortful, and stimulates the hormesis response and the ‘upregulation’ of vitagenes which results in all the neuroplasticity and health benefits described in my ebook ‘The Definitive Guide to Brain Cross Training’ (obtained with your software license).

When you set aside time to train with DNB Pro, try to ensure that you maximize the ‘core training’ effect by adopting the following principles:

  • Minimize going into ‘automatic pilot’ in the game. Ensure you are always putting in effort and the task is always challenging and absorbing.
  • Ensure that you work at successfully ignoring distracting information – focusing on only what is needed for target ‘matches’. When interference is high, focus and keep your accuracy levels high.
  • In the continuous stream of information, ensure that you continually update the contents of your working memory ‘workspace’, keeping track of the order.
  • Monitor your ongoing performance and try to develop effective intuitions about how to channel your effort, provided you try to stay clear of chunking, attention-hopping and playing the odds strategies.
  • Don’t assume that there is a linear relationship between n-back level and IQ level, and that by doing everything you can to improve your n-back will pay off in terms of IQ gains.
  • Don’t focus on your n-back level at the expense of the principles above.

Once you have optimized your n-back training, guided by the principles outlined in this tutorial, you can expect many benefits to your overall cognition.

  • Increased IQ (fluid intelligence).
  • Improved short term / working memory.
  • Improved ability to ignore distractions and focus on the task at hand.
  • Gains in reading comprehension.
  • Improved memory for personal events and experiences.
  • Reduced symptoms of ADHD and other attention disorders. 

GOAL TRACKING

Completing your full 20 Sessions with IQ Mindware apps requires a serious, sustained commitment. 

For this reason, it may be helpful to sign up with a goal-tracking, scheduling app that helps you achieve your 20 day ‘Profile completion’ goal.

Some people use the application Lift.  Others have used Irunurun which is Desktop and iOS mobile compatible. Here you sign up and set your weekly training goals (e.g. ‘8 half sessions per week’). Irunurun enables you to not only track your n-back brain training progress, but also any other goals you are working on – such as an exercise routine or an alternate day fasting routine.  You can also invite others by e-mail to share in tracking a particular goal.

We also recommend using Endomondo which functions in a similar way.

Endomondo for brain training

The guidelines for your training to build into your schedule are the following:

  • After a brief practice period you need to put aside time for 2 sessions of 15-20 minutes, for 20 days, making a total of 40 Sessions. These 20 days should be completed within a maximum of 6 weeks. You could also do the occasional half day.
  • You can combine the half sessions together in one sitting (really tough) or you can divide them into morning and afternoon/evening sessions. This means that on average for each week, you need to train 3-4 full Sessions a week. We do not recommend that you train for more than 5 full Sessions a week.
  • After this period, your training will have resulted in long term neuroplasticity change. However, we recommend you continue training for 1-2 hours per week to maintain the gains at their highest level.

Good luck with your training!

 

2 Comments

  • Thomas C. August 10, 2016 at 2:08 pm

    Does this apply to training with Emotional mode ON? Should it be always ON if improving Emotional resiliency is my main objective?
    Emotional mode doesn’t have any sound so no auditory targets means less benefits?

    • Mark Ashton Smith, Ph.D. August 16, 2016 at 10:29 am

      Yes, I’d recommend primarily training with emotional mode ON in this case – try going through the program. No need for the audio and it means that you can train anywhere with convenience.

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