Multi-store model

Atkinson and Shiffrin (1968)

• Three stores: sensory memory, STM, LTM.
• Information from the environment (environmental stimuli) goes to the sensory memory store - much of the information here is lost but if attention is paid to it, it will be transferred to the STM.
• STM → limited capacity & duration - if information is rehearsed it can be transferred to the LTM.
• Most information in the STM is displaced by incoming information.
• Once information is stored in the LTM it can be retrieved for use at a later date.

LTM

• Unlimited capacity, lasts a lifetime (Bahrick, 1975), encodes info semantically.

STM

• Holds 5-9 items (Jacobs, 1890), info remains for approx. 18 secs (Petersons, 1959), encodes info acoustically (Conrad, 1964).

• Shallice and Warrington - KF suffered brain damage - could no more than recall one or two items in a digit span test - no problems with LTM - supports idea that the STM and LTM are separate stores.
• LTM/STM distinction seen in people with Korsakoff's syndrome (memory disorder caused by prolonged alchohol abuse - people with this syndrome have reasonably intact STM but problems with LTM.
• Evidence for features of LTM/STM eg Conrad (1964), Petersons (1959).
• Simplistic - STM seems to be much more than a single unitary store - Shallice and Warrington's patient KF - STM problems restricted to verbal material - performed well on tasks with non-verbal material - suggests the STM must have at least 2 sound-based mechanisms.
• Model suggests there is one unitary LTM store - other researchers have suggested this is not the case - Tulving made a distinction between episodic and semantic memory - model does not distinguish these different types of LTM.