Example of a 1-back Condition:

The higher the value of N, the more difficult is the N-back task. In the upper figure, you see a 1-back task which is the easiest level. In this task, a response is required whenever the currently presented syllable or square is the same (i.e. at the same position) as the one that was presented just before.

Example of a 2-back Condition:

In this upper figure, there is a 2-back task. In this task, a response is required if the actual presented syllable or square is the same (i.e. at the same position) as the one that was presented 2 back in the sequence.

In order to respond to the square task, you have to push the left button. For the syllable task, you have to push the right button.

One run always consists of 20 + N trials. A trial consists of the presentation of a syllable and/or a square. Thus, in a 2-back task, you will be presented with 22 trials. Therefore, the length of a run is dependent on the level of N, but still lasts approximately one minute.

After hitting the “start” button, we start very easy with Level V1(visual, 1-back). That means, whenever the currently presented square is in the same position as the one presented 1 time ago, you have to press the button on the left side:

At the end of the run, you will receive a feedback concerning the performance of this particular run: 

The next run starts 5 seconds later and so on, until you press the stop or home button. Is the performance  100%, the value of N will be increased by one in the next run. If the performance is lower than 80%, the value of N will be decreased by one. Otherwise, the N-back level remains the same. 

The values shown in the feedback screen always address the amount of detected targets. Nevertheless, if you don’t push the button at all during a run, your percentage correct will still be 70% (because there were also trials in which you did not respond and that was correct!). However, in this case, the next level of N will be decreased by one.

So if your result is 100% you reach the Level V2(visual, 2-back). That means, whenever the currently presented square is in the same position as the one presented 2 back in the sequence, you have to push the button:

After Level V2 follows V3 and V4. Then we continue with Level A1(auditory, 1-back).Here you have to push the button on the right side, when you hear the same syllable as one time ago:

After Level A1 follows A2 and so on. After Level A4 we start with the dual n-Back task. In the dual n-back task, the auditory and visuospatial N-back tasks are combined. That is, the syllables and the squares will be presented at the same time. However, the value of N will be the same for both modality streams.

We start of course with level D1(dual, 1-back). That means, whenever the currently presented syllable is the same as the one presented 1 back in the sequence, You have to push the rightside button. Whenever the currently presented square is in the same position as the one before in the sequence, you have to push the leftside button.

So you might have to press just the left button, or just the right button, or both, or none at all. If the performance is equal 100% in both modalities, the value of N will be increased by one in the next run.

Training Recommendations:

You should play around 20 games per day. That's about 20-25 minutes a day. You can split the training to 3-4 sessions, like you want. With your iPhone or iPod you are able to train everywhere you want. If you are disturbed by someone, just press the stop button or the Home button, you loose nothing.

It's important to train everyday. On which level you play is not important, just keep on playing everyday. It's normal that you play at one level 2 or 3 weeks or longer and suddenly, one day you reach an higher level. It's like physical training. You can't use everyday more weight. You train a long time with the same weight, your muscles are growing, and suddenly you can use more weight.

With your brainpower, it's the same.