Editing Atkinson–Shiffrin memory model (section)

===Short-term store===
Short-term store takes on the form of a buffer, which has a limited capacity. The model assumes a buffer rehearsal system in which the buffer has a size, ''r''. Items enter the short-term store and accompany other items that are already present in the buffer, until size ''r'' has been reached. Once the buffer is at full capacity,  when new items enter, they replace an item, ''r'', which already exists in the buffer. A probability of 1/''r'' determines which already existing item will be replaced from the buffer.<ref name=RaaijmakersShiffrin1981 /> In general, items that have been in the buffer for longer are more likely to be replaced by new items.<ref name=PhillipsShiffrinAtkinson1967 />