<P> While much of the information in sensory memory decays and is forgotten, some is attended to . The information that is attended is transferred to the short - term store (also short - term memory, working memory; note that while these terms are often used interchangeably they were not originally intended to be used as such). </P> <P> As with sensory memory, the information that enters short - term memory decays and is lost, but the information in the short - term store has a longer duration, approximately 18--20 seconds when the information is not being actively rehearsed, though it is possible that this depends on modality and could be as long as 30 seconds . Fortunately, the information can be held in the short - term store for much longer through what Atkinson and Shiffrin called rehearsal . For auditory information rehearsal can be taken in a literal sense: continually repeating the items . However, the term can be applied for any information that is attended to, such as when a visual image is intentionally held in mind . Finally, information in the short - term store does not have to be of the same modality as its sensory input . For example written text which enters visually can be held as auditory information, and likewise auditory input can be visualized . On this model, rehearsal of information allows for it to be stored more permanently in the long - term store . Atkinson and Shiffrin discussed this at length for auditory and visual information but did not give much attention to the rehearsal / storage of other modalities due to the experimental difficulties of studying those modalities . </P> <P> There is a limit to the amount of information that can be held in the short - term store: 7 ± 2 chunks . These chunks, which were noted by Miller in his seminal paper The Magical Number Seven, Plus or Minus Two, are defined as independent items of information . It is important to note that some chunks are perceived as one unit though they could be broken down into multiple items, for example "1066" can be either the series of four digits "1, 0, 6, 6" or the semantically grouped item "1066" which is the year the Battle of Hastings was fought . Chunking allows for large amounts of information to be held in memory: 149283141066 is twelve individual items, well outside the limit of the short - term store, but it can be grouped semantically into the 4 chunks "Columbus (1492) ate (8) pie (314 → 3.14 → π) at the Battle of Hastings (1066)". Because short - term memory is limited in capacity, it severely limits the amount of information that can be attended to at any one time . </P> <P> The long - term store (also long - term memory) is a more or less permanent store . Information that is stored here can be "copied" and transferred to the short - term store where it can be attended to and manipulated . </P>

In the information processing model the first stage of memory is