Attention is one of the several functions that make up cognition. It can be considered a feature of perception by which a selection of stimuli take place. This discrimination determines an improvement in the collection of data from the environment. But it can also be considered a control mechanism by which the cognitive processes are ordered and monitored.

There are many definitions proposed, Ballesteros (2000) suggests the following: “attention is the process by which we can direct our mental resources on certain aspects of the environment or on the execution of certain actions that we consider most suitable among the possibilities. It refers to the state of observation and alert that allows us to become aware of what is happening in our environment”.

Depending on the classification criteria that we use, we distinguish different types of attention. In considering the origin of the stimuli we differentiate between internal and external attention. It may be voluntary or involuntary depending on the attitude of the subject. When there are motor or physiological manifestations it is called open. The interest of the subject on several or just one stimulus determines the divided or selective attention, respectively. When we talk about the sensory modality, we find the visual or spatial attention and the auditive or temporary attention.