The process of building mental images. This is a process of interception (=perception based on impressions from within), as opposed to exteroception (=perception based on impressions from without). Visualization is often used in personal growth to create mental pictures of a reality that does not yet exist and that one would like to create.
It can also be used to practice, to prepare oneself to behave or perform in a certain way in the future when a certain situation arrives, such as a job interview, an athletic performance, or a difficult conversation.
Visualization can also be misused if you mentally create and dwell on images of a reality that you do not want to see materialize.
Since the subconscious part of the mind can not discern between what is real and what is imagined, visualization can create certain emotions that mirror the mental programs that one is running.