Types of LTM

• LTM is too simplistic


  One criticism of the Multi-Store model of memory was that its view of the LTM is too simplistic.

  • Commentators suggested that LTM comprises a number of different stores rather than being one unitary store.

  • This theory was developed when case studies of brain damaged individuals showed that certain types of long term memories were affected when others were not. This implied that different types of information was stored in different areas of the brain which fits in with the idea that there are distinct and separate long-term stores.
• Types of LTM


  1 Procedural memory

  2 Semantic memory

  3 Episodic memory

  
  

  Both episodic and semantic memory are types of declarative memory.
• Procedural memory


  Procedural memory is knowing how to perform tasks - it is a less conscious type of memory which makes it more resistant to memory loss. Is is a motor, action based memory store.
• Semantic memory


  Semantic memory is a memory store for facts which records general knowledge, such as knowing a bike has 2 wheels.
• Episodic memory


  Episodic memory is an autobiographical memory store which records personal life events and experiences including feelings, for example the day you first rode a bike without stabilisers.
• Evidence for LTM stores 1


  Cohen and Corkin used a sample of individuals who had severe amnesia and trained them to do a complex visuospatial puzzle over a number of trials until they reached the point they were able to complete the puzzle without errors.

  
  

  The researchers found that each time the participant completed the puzzle, they were amazed at their ability to do so as they had no memory of being taught how to complete the puzzle.

  
  

  The participants' procedural memory was intact and functioning as they were able to remember how to do the puzzle. However, they were unable to remember when they had learnt to do it therefore their episodic and semantic memory were not functioning as normal. The fact that procedural memory was working but the declarative memory stores were not shows that they are distinct stores.
• Evidence for LTM stores 2


  Graf et al carried out a memory test on a sample of individuals with severe amnesia. They gave them a list of words to learn and to be recalled later.

  
  

  when the participants had to recall the words, they were unable to do so as they had no memory of learning the words. But in the word association task they responded with many of the words from the list they had learnt.

  
  

  The participants episodic memory was not working as they could not remember having to learn the list. However, the fact they responded with words from the list meant the semantic memory was still functioning. The fact that semantic memory was working when episodic memory was not shows that they must be separate stores.
• Evaluating the idea of different LTMs


  Procedural memory correlates with activity in the basil ganglia and the cerebellum whereas declarative memory correlate with other parts of the brain. However, both episodic memory and semantic memories are related to activity in the hippocampus and surrounding structures in the temporal lobe suggesting these memories are not as distinct from each other as procedural memory is from them.

  
  

  Some psychologists have argued it is not possible to separate episodic memories from semantic memories. The point is that everything we know we must have learnt at some point in our lives, and therefore it is impossible to tease apart facts from actual events. For example, when we answer a question correctly in a quiz it must be apart of our general knowledge, but we may also remember it from when or where we learnt it.

  
  

  Schank offers an alternative model which sees episodic and semantic memories being held in the same store but with more general memories (i.e. semantic-type memories) being stored at a higher level, and more specific memories (i.e. episodic-type memories) being stored at a lower level.

  His theory is that when we first learn a fact it is stored at the lowest level, and we can generally remember where we learnt it, who from, etc. As we encounter that piece of information more and more from different sources, we incorporate it into our general knowledge, and it becomes stored at a higher level. At this point, we have forgotten how we first learnt it. However, there are some facts that are so significant that we never forget how we learnt them, and these would stay stored at the lower level.