What if you could train your brain to increase your intelligence in the same way that you train your body to build muscle? According to a performance task known as n-back, this prospect is a reality.
What is N-Back?
N-Back is a test in which a subject is presented with a sequence of stimuli (images, sounds) and is tasked with indicating when the current stimulus matches the one from n, a variable for an indicated number given steps earlier in the sequence. The n can be adjusted to increase or decrease the difficulty of the task. 
The premise may seem very similar to memory games such as “Concentration,” but with a very important difference. In the N-Back task there is no fixed points to remember on a board, but instead a single item that changes position each turn. Depending on the variable n, the subject is then tasked with remembering the position of the item 1, 2, or more turns back. 
Wayne Kirchner’s original n-back task was created in 1958, but a new variation called the dual n-back was created in 2003 by Susanne Jaeggi. This version is built around the same basic premise as the original, with the difference being that it involves two different sequences. Often they will be based on separate senses, such as one visual and one audio sequence working in tandem. 
Ok, But How Does This Make Me Smarter?
To understand how the dual n-back sequence works, it must be clarified that there are two distinct types of intelligence as classified by those in the field of psychology.
The first type is known as crystallized intelligence. This is the stored up knowledge that a person uses to do something such as riding a bicycle or go swimming. This is the kind of intelligence that dictates the way we remember how to complete tasks. 
Fluid Intelligence is the second and much more fickle variety. This is the type of intelligence that forms our capacity to learn, reason, solve problems, and develop connections between things. Fluid intelligence peaks during early adulthood and slowly declines from there. Until recently it was thought impervious to conditioning. 
However, using this seemingly simple game, we can target working memory, the fluid short-term memory that we can use to manipulate and change information stored in our brains. Once we begin to improve our short term memory, our capacity to learn increases exponentially. 
Where Can I Try the N-Back Task?
There are a number of different activities based around n-back, such as this online dual n-back game that will help get you started on training your brain.