Memory (MSM model)

• The Multi-Store Model of Memory

  The multi-store model of memory (also known as the modal model) was proposed by Atkinson and Shiffrin (1968) and was one of the first models of memory.
• Memory stages

  • For a memory to go into storage (i.e. long-term memory), it has to pass through three distinct stages: the sensory register, short-term memory, and finally long-term memory. 
  • These stages were first proposed by Richard Atkinson and Richard Shiffrin.
  • Their model of human memory is called Atkinson-Shiffrin (A-S). It is based on the belief that we process memories in the same way that a computer processes information.
• Memory variables

  • There are three variables that can be used to describe the stores that information passes through: coding, capacity and duration.
  • Coding is the process of changing information from the environment to store it in memory.
  • Capacity is the amount of information that can be stored.
  • Duration is the time period that information is held in the memory stores.
• Short-Term Memory

  Short-term memory (STM) is the point of processing sensory memory. This then determines whether information is moved into long-term memory or not.
• Short-term memory (STM)

  • Short-term memory (STM) is a temporary storage system that processes incoming sensory memory. 
  • Short-term memory takes information from sensory memory and sometimes connects that memory to something already in long-term memory. 
  • Short-term memory storage lasts about 20 seconds (estimated to be between 18 and 30 seconds).
• Rehearsal


  The conscious repetition of information that you want to remember
• Rehearsal


  May help to move information from STM into long-term memory - which is called memory consolidation
• STM capacity

  • In his research on the capacity of memory, George Miller (1956)found that most people can retain about seven items in STM. 
  • Some remember five, some nine, so he called the capacity of STM seven plus or minus two.
  • Some factors affect our STM. For example, numbers recall is better than letters, and acoustic coding tends to be better than visual coding.
• Summary

  • Duration: 18-20 seconds.
  • Capacity: seven +/- two items.
  • Coding: primarily acoustic.
• Long-Term Memory

  Long-term memory is like the brain's hard-drive. It is theorised to have an unlimited capacity. Most of the time, information can be retained and moved back into short-term memory - but you may need a prompt.
• Long-term memory (LTM)

  • Long-term memory (LTM) is the continuous storage of information. 
  • Unlike short-term memory, the storage capacity of LTM has no limits. 
  • LTM contains everything that you can remember, even if it happened 2 minutes ago, weeks ago or years ago.
• Information processing in LTM

  • Sticking with the computer analogy, the information in your LTM would be like the information you have saved on the hard drive. 
  • Information stored on the hard drive isn't visible on your computer screen (or in your immediate short-term memory), but you could probably access (or remember) the information if you wanted to.
• Long-term memories


  Not all are remembered equally strongly
• Long-term memories


  • Some are harder to remember
  • Prompts (or memory cues) can make it easier to access a memory
• Easily recalled memories

  • Fact - "What is the capital of the United States?"
  • Procedure - "How do you ride a bike?"
• Prompts or memory cues

  Help recall a hard to remember memory, like the name of the restaurant
• Summary

  • Duration: unlimited.
  • Capacity: unlimited.
  • Coding: primarily semantic but can be others.
• Long-Term Memory

  Long-term memory can be split into implicit and explicit memory. Explicit memory can be split into semantic & episodic memory and implicit memory can be classified as procedural or not.
• Long-term memory (LTM)

  • Long-term memory is divided into two types: explicit and implicit.
  • Understanding the different types is important because a person’s age or particular types of brain trauma or disorders can leave certain types of LTM intact while having disastrous consequences for other types.
• Explicit memory

  • Explicit memories are those we consciously try to remember and recall. 
  • For example, if you are studying for your chemistry exam, the material you are learning will be part of your explicit memory.
  • Sometimes, but not always, the terms explicit memory and declarative memory are used interchangeably.
• Implicit memory

  • Implicit memories are memories that are not part of our consciousness. 
  • They are memories formed from behaviours. 
  • Implicit memory is also called non-declarative memory.
• Procedural Memory

  Procedural memory is a type of implicit memory that stores the knowledge of how to perform actions.
• Procedural memory

  • Procedural memory is a type of implicit memory: it stores information about how to do things. 
  • There is no conscious recall of procedural memory.
• Example of procedural memory

  • For example, it is the memory for skilled actions, such as how to swim front crawl.
  • If you are learning how to swim front crawl, you practice the stroke: how to move your arms, how to turn your head to alternate breathing from side to side, and how to kick your legs. 
  • You practice this many times until you become good at it.
  • Once you learn how to swim front crawl and your body knows how to move through the water, you will never forget how to do it, even if you do not swim for a couple of decades.
• Explicit memory

  Explicit or declarative memory is associated with the storage of facts and knowledge that we have personally experienced and can consciously recall.
• Explicit (declarative) memory

  • Declarative memory has to do with the storage of facts and events we personally experienced. 
  • Explicit (declarative) memory has two parts: semantic memory and episodic memory.
• Semantic memory

  • Semantic means having to do with language and knowledge about language. 
  • Stored in our semantic memory is knowledge about words, concepts, and language-based knowledge and facts. 
  • For example, answers to the following questions are stored in your semantic memory:
  • Who was the first President of the United States?
  • What is democracy?
• Episodic memory

  • Episodic memory is information about events we have personally experienced. 
  • The concept of episodic memory was first proposed about 40 years ago. 
  • Currently, scientists believe that episodic memory is memory about happenings in particular places at particular times, the what, where, and when of an event. 
  • Episodic memory involves the recollection of visual imagery as well as the feeling of familiarity.
• Glanzer & Cunitz (1966) The Serial Position Effect

  Research aim: to investigate whether STM and LTM are different memory stores.
• Glanzer & Cunitz:

  Procedure: Participants were given a list of common words to memorise. They were then asked to recall as many as possible. Results: Participants remembered more words on average from the beginning (the tendency to remember more words from the beginning is called the primacy effect) and end (the tendency to remember more words from the end is called the recency effect) of the list than the middle. This is known as the serial position effect.
• Glanzer & Cunitz:

  Conclusion

  • Participants remembered more words from the beginning of the list because they had been transferred by rehearsal to the long-term memory. 
  • Words at the end of the list were still in the STM.
  • Words in the middle were forgotten because of the limited capacity of the STM (7 +/– 2 (Miller)).
  • This supports the theory that the MSM that STM and LTM are separate stores.
• Evaluation of Glanzer & Cunitz 

  • Strengths
  • Reliable – easy to replicate. 
  • Practical applications for improving memory of important information. 
  • Limitations
  • Lacks ecological validity – not how we use memory in everyday life.
• Milner et al (1966) - Case Study on Epilepsy Patient HM

  HM suffered from severe epilepsy. He underwent surgery. However, the surgery went wrong and destroyed his hippocampus, leaving him with severe anterograde amnesia. This meant he was unable to make any new memories.
• Research aim and method

  • Research aim: To investigate anterograde amnesia. 
  • Research method: A case study using numerous psychometric tests, experiments and observations.
• Results

  • HM did have the ability to learn new motor skills so his procedural memory was intact. But he could not make new episodic or semantic memories. He had a working memory as he was able to hold conversations. His issue was that his STM and LTM were no longer connected.
• Conclusion

  • Cases of brain damage, such as HM, support the distinction between LTM and STM.
  • Damage to the hippocampi destroys LTM and leaves patients trapped in a world of experiences which only last as long as their STM.
• Evaluation 

  • Strengths
  • In depth and detailed. 
  • Limitations
  • Cannot generalise from a case study.
• Korsakoff’s Syndrome & Limitations of the Multi-Store Model

  Here's how Korsakoff's syndrome provides evidence in support of the multi-store model of memory. There are some limitations to the model.
• Korsakoff’s syndrome

  • Chronic alcoholics sometimes develop Korsakoff’s syndrome, which causes brain damage.
  • However, it has little effect on STM, but severely impairs LTM. This suggests that STM and LTM are stored in different areas of the brain. This provides further evidence to support the multistore model of memory
• Limitations of the MSM of memory

  • It is likely that there is more than one type of STM. Certain types of brain damage show deficits with different areas of STM. Similarly, LTM has more than one type.
  • What is rehearsal? The model states maintenance rehearsal as a way of practicing and maintaining memories. However, rehearsal can also be elaborative – building on what you already know.
  • It is unlikely that memory is linear. It is more likely to be interaction between the memory stores, as suggested by the working memory model (WMM).