Multi-Store Model

• The model was proposed by Atkinson and Shiffrin (1968, 1971), and aims to explore memory shifts between different storage systems.

  
  

  The three memory structural components are the sensory register, short-term memory, and long-term memory.
• 𝙎𝙀𝙉𝙎𝙊𝙍𝙔 𝙈𝙀𝙈𝙊𝙍𝙔:

  Functions to retain information for long enough to decide if information is worthy for further processing.

  
  

  There are many sensory stores, the two important examples of sensory stores are: visual (iconic) memory and auditory (echoic) memory.

  
  

  Information that isn't rehearsed is lost quickly.

  
  

  After information is selected from sensory memory and is attended to, it is transferred to short-term memory.
• 𝙇𝙊𝙉𝙂-𝙏𝙀𝙍𝙈 𝙈𝙀𝙈𝙊𝙍𝙔:

  Long-term memory is considered to be relatively permanent.

  
  

  The information isn't the exact replica of events or facts but is stored as an outline.

  
  

  Memories can be distorted when retrieved as we fill in gaps to create a more meaningful memory.
• 𝙋𝙍𝙊𝘾𝙀𝙎𝙎𝙀𝙎:

  • Encoding: transforming sensory inputs into a form that can be stored in memory.

  
  

  • Storage: holding process of memory.

  
  

  • Retrieval: information is transferred from LTM to STM in recall.
• 𝙄𝘾𝙊𝙉𝙄𝘾 𝙈𝙀𝙈𝙊𝙍𝙔:

  Temporary storage for information received visually (visual system).

  
  

  Duration of iconic memory approx. 0.2 - 0.4 seconds.

  
  

  Each image is registered in iconic memory before the previous image fades, viewing the world in a continuous manner (similar to a series of frames that makes a movie seem continuous).
• 𝙀𝘾𝙃𝙊𝙄𝘾 𝙈𝙀𝙈𝙊𝙍𝙔:

  Stores information received aurally (auditory system).

  
  

  Duration of echoic memory is approx. between 3 - 4 seconds after the stimulus is perceived.

  
  

  Believed to be necessary for comprehension of many sounds; after hearing combination of syllables, the definition of the word is apparent.

  
  

  Similar to iconic memory, echoic memory stores lots of incoming information and these information are held in an unprocessed form.
• 𝙎𝙀𝙍𝙄𝘼𝙇 𝙋𝙊𝙎𝙄𝙏𝙄𝙊𝙉 𝙀𝙁𝙁𝙀𝘾𝙏:

  This effect is when the retrieval or recall of information varies according to the relative position of the material; recall is usually better at the beginning and the end of a list than the middle.

  
  

  This effect supports the two distinct sub-systems of memory, long-term and short-term memory.
• 𝙋𝙍𝙄𝙈𝘼𝘾𝙔 𝙀𝙁𝙁𝙀𝘾𝙏:

  This effect is when the first few items in a list are recalled well, when compared with middle items, during a free recall test. This is usually attributed to more successful rehearsal of the first few items, which enters long-term memory and can be retrieved later on.

  
  

  Items are probably rehearsed and transferred to LTM before STM's capacity is full. It is likely that items from the start of the list would be forgotten unless they are stored in LTM.
• The multi-store model of memory, proposed by Richard Atkinson and Richard Shiffrin, explains how information flows through the memory system
• It consists of three memory stores: sensory memory, short-term memory, and long-term memory
• Sensory memory is the first stage of memory processing, registering sensory information briefly, including iconic memory (visual) and echoic memory (auditory)
• Short-term memory is the second stage, holding information temporarily for about 18-30 seconds, with a limited capacity of around 7 items
• Information in short-term memory is coded acoustically and can be transferred to long-term memory through consolidation.
• Long-term memory is the final stage, storing information for a longer period (up to a lifetime) with an unlimited capacity
• The multi-store model oversimplifies memory, not considering the complex nature of memory storage or the role of attention and emotion
• Strategies to improve memory include repetition, elaboration, visualization, adequate sleep, regular exercise, and stress reduction
• 𝙎𝙃𝙊𝙍𝙏 𝙏𝙀𝙍𝙈 𝙈𝙀𝙈𝙊𝙍𝙔

  Less than 0.01% of all sensory information received by human senses every second reaches consciousness. Information that isn't lost from sensory memory is transferred to STM (the temporary memory store).

  
  

  Duration of STM is longer than sensory memory, approx. 18 - 30 seconds. Decay (forgetting information) occurs at approx. 12 seconds if information is unrehearsed.

  
  

  Rehearsal keeps information in STM and aids the transfer of information from ST to LT memory. Maintenance rehearsal is maintaining information in STM by using mental repetition.
• 𝙍𝙀𝘾𝙀𝙉𝘾𝙔 𝙀𝙁𝙁𝙀𝘾𝙏:

  This effect is when the final few items in a list are recalled well, when compared with middle items, during a free recall test. This is usually attributed to the final words being retained in STM.

  
  

  Recency effect would still occur even if the list of items is increased. Maintenance rehearsal is probably used to retain the information.

  
  

  Middle items are presented too late to be adequately rehearsed and transferred into LTM, but too early to be held in STM without rehearsal (imagine a U-shaped graph).
• The model suggests that memory is made up of three stores linked by processing.
• The Multi-Store Model of Memory:

  A) Retrieval

  B) Register

  C) Rehearsal

  D) Long-term memory

  E) Short-term memory

  F) Attention

  
• 𝙏𝙃𝙀 𝙎𝙀𝙉𝙎𝙊𝙍𝙔 𝙍𝙀𝙂𝙄𝙎𝙏𝙀𝙍:

  A stimulus from the environment - e.g. the sound of someone's name - will pass into the sensory register along with lots of other sights, sounds, smells, etc. This part of the memory has one store for each of our senses.

  The two main modality-specific stores:

  1. Iconic Memory: visual information coded visually
  2. Echoic Memory: auditory information coded acoustically

  Material duration is only half a second, however the SR has a very high capacity. Information only passes into the memory system if you pay attention to it (attention = the key process).
• 𝙎𝙃𝙊𝙍𝙏-𝙏𝙀𝙍𝙈 𝙈𝙀𝙈𝙊𝙍𝙔:

  The STM is a limited-capacity store which stores information temporarily - for about 18 seconds. Information here is coded acoustically. It has a capacity on average of 7±2 items.

  
  

  Maintenance rehearsal occurs when we repeat information to ourselves over and over again. Information remains in the STM as long as it is rehearsed, and if it is rehearsed long enough, it passes into the LTM.
• 𝙇𝙊𝙉𝙂-𝙏𝙀𝙍𝙈 𝙈𝙀𝙈𝙊𝙍𝙔:

  The LTM is a potentially permanent memory store for information that has been rehearsed for a prolonged time. Its duration may be up to a lifetime.

  
  

  Bahrick et al. (1975) found that many participants of his study were able to recognise the names and faces of their classmates 50 years after graduating.

  
  

  LTM is coded semantically and its capacity is thought to be unlimited. When we want to recall information from the LTM it has to be transferred back into the STM by a process called retrieval.

  
  

  Information is lost from the LTM by decay and interference.
• 𝙀𝙑𝘼𝙇𝙐𝘼𝙏𝙄𝙊𝙉𝙎:

  1. research support (Baddeley)
  2. limitation of research support
  3. more than one STM (Shallice and Warrington)
  4. elaborative rehearsal (Craik and Watkins)
  5. supporting evidence (HM)
  6. oversimplified model
• 𝟭. 𝗥𝗘𝗦𝗘𝗔𝗥𝗖𝗛 𝗦𝗨𝗣𝗣𝗢𝗥𝗧:

  A strength of the MSM is that many studies prove the STM and LTM are different.

  For example, Baddeley (1966) found that when using our STM, we tend to mix up words that sound similar, but when using our LTM we mix up words that mean similar things. Further support comes from studies into capacity and duration.

  The strength of this study is that it clearly shows that coding in the STM is acoustic whereas it is semantic in the LTM. They are different, which supports the MSM's view that these two memory stores are separate and independent.
• 𝟯. 𝗠𝗢𝗥𝗘 𝗧𝗛𝗔𝗡 𝗢𝗡𝗘 𝗦𝗧𝗠:

  A weakness of the MSM is that it states the STM is a unitary store.

  Shallice and Warrington (1970) studied a patient with amnesia called KF. His STM for digits was very poor when they were read aloud to him, but his recall was much better when he read the digits to himself. Further studies of KF and others showed that there could possibly be another STM store for non-verbal sounds.

  This evidence suggests that the MSM is wrong in claiming that there is just one STM store processing different types of information.
• 𝟮. 𝗟𝗜𝗠𝗜𝗧𝗔𝗧𝗜𝗢𝗡 𝗢𝗙 𝗥𝗘𝗦𝗘𝗔𝗥𝗖𝗛 𝗦𝗨𝗣𝗣𝗢𝗥𝗧:

  In everyday life we form memories related to all sorts of useful things - people's faces, their names, facts, places, etc.

  But many of the studies that support the MSM used none of these materials. Instead, they used digits and letters (Jacobs), word lists (Baddeley), or consonant syllables with no meaning (Peterson and Peterson).

  This means that the MSM may not be a valid model of how memory works in our everyday lives where we have to remember much more meaningful information.
• 𝟰. 𝗘𝗟𝗔𝗕𝗢𝗥𝗔𝗧𝗜𝗩𝗘 𝗥𝗘𝗛𝗘𝗔𝗥𝗦𝗔𝗟:

  Another limitation of the MSM is that prolonged rehearsal is not needed for transfer to the LTM.

  According to the MSM, what matters about rehearsal is the amount of it - the more you rehearse, the less likely you are to forget. This is prolonged rehearsal.

  However, Craik and Watkins (1973) found that the type of rehearsal is more important; they found elaborative rehearsal is needed for LT storage. This occurs when you link information to your existing knowledge.

  This suggests the MSM does not fully explain how LT storage is achieved.
• 𝟱. 𝗦𝗨𝗣𝗣𝗢𝗥𝗧𝗜𝗡𝗚 𝗘𝗩𝗜𝗗𝗘𝗡𝗖𝗘:

  A study of an individual with a memory disorder, referred to as HM, supports the MSM.

  HM underwent brain surgery to relieve his epilepsy, however as the surgery procedure was still in infancy, both of his hippocampus were removed (central part to memory function).

  When his memory was tested in 1955, he thought the year was 1953.

  His LTM was tested repeatedly but never improved with practice. However, he performed well on tests of immediate memory span.

  This reinforces the MSM's point of there being two separate memory stores for ST and LT memory.
• 𝟲. 𝗢𝗩𝗘𝗥𝗦𝗜𝗠𝗣𝗟𝗜𝗙𝗜𝗘𝗗 𝗠𝗢𝗗𝗘𝗟:

  Atkinson and Shiffrin based the MSM on research evidence available at the time that showed the STM and LTM to be single memory stores, separate and independent from each other.

  However, there is a lot of research evidence that LTM, like STM, is not a unitary memory store. For example, we have one LT store for our memories of facts about the world, and a different store for memories about how to ride a bike.

  Combined with research showing that there is more than one type of both STM and rehearsal, the MSM is an oversimplified model of memory.
• The sensory registers have a very large capacity and brief duration because there is a very large amount of information coming in from the environment which needs to be recorded. The data is constantly changing so it is important that the memory is constantly refreshed.
• • Sensory register: Iconic (visual) and echoic (sound) stores for stimuli from the environment – very brief duration and large capacity.
  • STM: Mainly acoustic coding, limited duration (about 18 seconds), limited capacity (5 - 9 items on average).
  • LTM: Mainly semantic coding, duration up to a lifetime, unlimited capacity.
  • Main processes: Information is transferred from STM to LTM by rehearsal and from LTM to STM by retrieval.
• The case of HM supports the central feature of the MSM – that there are two separate and independent memory stores, STM and LTM.

  What happened to HM is evidence that it is possible to sustain damage to one store with the other remaining relatively unaffected.

  HM's LTM was badly damaged. He had no memory for events that happened minutes earlier. His LTM never improved with practice. Testing showed that his STM was much better: his digit span showed that he could recall information that was presented to him immediately.

  Clinical psychologists call this difference in performance a dissociation.