Describe the Multi-Store Model

Atkinson and Shiffrin's Multi Store Model (1968) describes how information is encoded by passing through 3 memory 'stores' . Visual and audible information enters the Sensory Store but is only stored for less than 1 second. If attention is paid, it passes into the Short-Term Memory (STM) Store, where it is stored acoustically. The STM Store can hold about 7 pieces, or 'chunks', of information (plus or minus 2) for up to 18 seconds. If this information is rehearsed, it passes into the Long Term Memory (LTM) Store, where it is stored semantically (i.e. is has meaning). The LTM store has a potentially unlimited capacity and duration of storage.
*** A way of understanding this is thinking about trying to remember a phone number. First you must see or hear the number (it enters the Sensory Store) and also pay attention (so it enters the STM store). You may then repeat it to yourself to keep it in your STM store and so you can remember it in future (so it has entered your LTM store). This also demonstrates that the information is encoded acoustically. In the LTM store, you might encode a number semantically by encoding it as your own number, your parent's number or an emergency number.