Multi-store model of memory

• Atkinson and Shiffrin's multi-store model describes how information flows through the memory system. The model suggests that memory is made up of 3 stores linked by processing.
• A stimulus from the environment will pass into the sensory registers along with lots of other sights, smells and so on. So this part of memory is not one store but several, in fact one for each of the five senses.
• Sensory register = the memory stores for each of our five senses
• The two main stores in the sensory register are called iconic memory (visual information is coded visually) and echoic memory (sound information is coded acoustically).
• Material in sensory registers lasts only very briefly- the duration is less than half a second. The sensory registers have a high capacity. Very little of what goes into the sensory register passes further into the memory system, unless you pay attention to it. So the key process it attention.
• Information from the sensory registers passes to the short-term memory store (STM).
• Information in the STM is coded acoustically and lasts about 30 seconds unless it is rehearsed.
• Maintenance rehearsal = when we repeat material to ourselves over and over again.
• We can keep information in our STMs so long as we rehearse it. If we rehearse it long enough, it passes into long-term memory (LTM).
• LTM is the potentially permanent memory store for information that has been rehearsed for a prolonged time.
• Psychologists believe the capacity of the LTM is unlimited and can last many years. LTMs tend to be coded semantically.
• Although this material is stored in LTM, when we want to recall it, it has to be transferred back into STM by a process called retrieval.
• A strength of the MSM model is that it is supported by research studies that show that STM and LTM are indeed qualitatively different. Baddeley found we tend to mix up words that sound similar when we are using our STMs , but we mix up words that have similar meanings when we use our LTMs. This shows that coding in STM is acoustic and coding in LTM is semantic. So they are different, this supports the MSM's view that these two memory stores are separate and independent.
• The MSM states that STM is a unitary store, in other words there is only one type of short-term memory. However, evidence from people suffering from amnesia shows this cannot be true. Shallice and Warrington studied a patient with amnesia known as KF. They found that KF's short-term memory for digits was very poor when they read them out loud to him. But his recall was much better when he read the digits himself. Therefore research shows there must be at least one short-term store to process visual information and another to process auditory information.
• According to the MSM, what matters in rehearsal is the amount of it that you do. So the more you rehearse, the more likely you are to transfer it to LTM and remember it. However, Craik and Watkins found what really matters about rehearsal is the type. Maintenance rehearsal just maintains information 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. This is a limitation of the model as it is another research finding that cannot be explained by the model.