Multi-store Model

• Devised by Atkinson and Shiffrin in 1968.

  This theoretical model seeks to explain how information is transmitted from the outside world through different stores of memory, and how it is processed at each point.
• Information arrives at a part of the mind called the Sensory Register. 

  
  

  The capacity is unlimited, the duration is 250milliseconds . Coded in whatever form it was perceived in (modality specific).

  
  

  Each kind is stored in a different store within the sensory register depending on which sense organ the information came from. Visual memory is stored in the Iconic store, sound in the Echoic store, etc.  
• Iconic Store - visual images are held here for about ¼ second. It has an unlimited capacity but only holds one image at a time. The iconic store can hold up to seven items at once. This means that if we see more than seven objects our attention will be drawn away from some of them so they won’t enter into our short term memory.
• Echoic Store – sounds are held here for about two seconds. It also has an unlimited capacity but only holds one item at a time. If we hear more than one thing then our attention will be drawn away from some of them so they won’t enter into our short term memory.
• The Short Term Memory store is the second store.

  •  It has a duration of about 18-30 seconds. 
  • Only information that is rehearsed here will pass into the next store, and the rest will be lost, as by rehearsing information we can keep it in the store for longer than 18-30 seconds. Short term memory is coded acoustically as the information is rehearsed using our internal voice.
• The two kinds of rehearsal are:

  • Maintenance rehearsal keeps the information in the short term memory for longer, and it may pass into the long term memory eventually.
  • Elaborative rehearsal is where we semantically encode the information (give it meaning), moving it directly from the short term memory to the long term memory. 
• The last store is the Long Term Memory. 

  • Information in the LTM has an unlimited duration and it has an unlimited capacity. Information in our long term memory may be lost (we lose access), but this may be regained later. 
  • Information in the LTM is coded semantically. 
  • To use the information we need to bring it out of the LTM and back into the STM. This process is called retrieval.
  • Unlike the short and LTM the sensory register is not under conscious control; it is recorded automatically. Any information found in the short or long term memory is initially gathered by the sensory register.
• Supports

  • Research studies

  show that STM and LTM are indeed qualitatively different. For example, Baddeley found that we tend to mix up words that have similar meanings when we use LTM.

  • Baddeley’s study clearly shows that coding in the STM is acoustic and in the LTM is semantic. So they are different, and this supports the MSM’s view that these two memory stores are separate and independent.

  Supporting research adds validity to the idea that the STM and LTM are separate stores.
• First limitation

  • More than one type of STM.

  The MSM states the STM is a unitary store but this may not be the case, at the very least there must be one other store to process visual information and another to process auditory information. The WMM includes these as separate stores.

  Shallice and Warrington (1970) studied a patient with amnesia known as KF. They found that his memory for digits was very poor when they were read out loud to him, but when he read them himself his memory improved significantly showing that there could be another STM memory store for non-verbal sounds.
• Second limitation

  • Type, not amount. 

  MSM says what matters in rehearsal is the amount of it you do. However, Craik & Watkins (1973) discovered there are two types of rehearsal. Maintenance rehearsal is in the MSM, but does not transfer info into the LTM. It just maintains it in the STM. Elaborative rehearsal is needed for long-term storage. This occurs when you link the information to your existing knowledge, or you think about what it means.
• Third limitation

  • Artificial materials 

  In everyday life, we form memories related to all sorts of useful things

  people’s faces, their names, facts, places, etc. However, a lot of the research studies that provide support for the MSM used none of these materials. Instead, they used digits, letters, and sometimes words. They even used what are known as consonant syllables that have no meaning (such as ZLG).

  The artificial materials question the validity of support to MSM and also a lack of mundane realism.