Atkinson and Shiffrin's Multistore Model of Memory suggests that there are three separate memory stores, Sensory Memory (sometimes called the 'sensory store'), Short Term Memory (STM) and Long Term Memory (LTM). Each store has a different duration, capacity and mode of encoding (the way that information is stored - e.g., visual, acoustic, semantic).

Baddely and Hitch believed that the STM store in the Multistore Model was too simplistic: they thought that short term memory was not a passive store, but several active processes that manipulate information.