Obtaining an understanding of the structure and functioning of human memory is a major pursuit in modern psychology, because it is necessary for the understanding of learning, cognition, and other major conscious and unconscious processes. .
Memory is an important function in learning a list of words or other experimental material, for example one cannot learn without paying attention or orientating to written material, thus researchers have given groups different orientating tasks. These tasks caused them to attend to materials while performing various cognitive operations. The purpose of the orientating tasks was to assure the participants attended to the materials while concealing from them the fact that they were going to be tested for recall to see how deep the cognitive learning is. .
Several models of human memory have been developed based on the idea that there are separate memory systems or stores. The most influential of these was an information-processing model proposed by Atkinson and Schriffrin (1968) proposed a multistore model of memory, that consisted of sensory, short-term and long-term stores with different functions, capacity and persistence of the stored information. .
Theories like this type dominated the area of human memory for a number of years. Other researchers elaborated on the model, identifying additional structural components to each of the stores. Baddley (1992) suggests that short-term store consists of components he calls the phonological loop, the visuo-spatial sketchpad, and the central executive. .
The above authors emphasize on the importance of rehearsal of audio-verbal material in short-term memory before it can be copied to the permanent long-term store, as a result of this many unrehearsed material is lost. .
In 1972, theorists published a paper in which they argued that existing experimental evidence did not provide much support for the multistore model; they showed that the distinctions between the different memory stores were, at best, very fuzzy.