Some theorists view short - term memory as a working memory, in which information is retrieved and manipulated. In this view, it is a central executive processor involved in reasoning and decision-making
a set of temporary memory stores that actively manipulate and rehearse information
visual store (visual and spatial information)
verbal store (speech, words, numbers)
episodic buffer (episodes or events)
It uses significant amount of cognitive resources during its operation. In turn, it makes us less aware of our surrounding.
A basic principle is that some information gets lost during each process. You notice only a small part the world that confronts you; you encode only a small part of what you notice; and you retrieve only part of what was previously stored in your memory.