Types of Long-Term Memory

• Types of LTM

  - Tulving (1985) was one of the first cognitive psychologists who realised that the MSM's portrayal of LTM was too simplistic and inflexible.

  - He proposed that there are 3 types of long-term memory: episodic, semantic and procedural.
• Episodic memory


  - Refers to our ability to recall events/episodes from our lives.

  - It is often likened to a diary - a record of personal experiences.

  - Episodic memories are complex.

  - They are time-stamped; we know when they happened and what happened.

  - Memories of a single episode will include several elements, e.g. people, places, objects, behaviours etc. These elements are all interwoven to produce a single memory.

  - Recall requires a conscious effort. This is done quickly, but we are aware that we need to search for a memory when trying to recall it.
• Semantic memory

  - Contains our shared knowledge of the world.

  - Likened to a combination of an encyclopaedia and dictionary.

  - Semantic memories are not time-stamped; we don't know when we first heard a new piece of information.

  - Semantic memories are less personal and more about knowledge and facts that we all share.

  - It contains an immense volume of information that is constantly being added to as we learn new things.

  - Tulving said that it is less vulnerable to distortion and forgetting than episodic memory.
• Procedural memory

  - Our memory for learned actions or skills.

  - Procedural memories can be recalled without conscious effort.

  - These skills are often difficult to try to explain to someone else.
• Evaluating types of LTM: Clinical evidence (with counterpoint)

  - The proposition that there are different types of LTM are supported by the case studies of HM and CW.

  - Episodic memories of HM and CW were both impaired due to brain damage, however, their semantic memories remained intact; e.g. they still knew the meanings of words.

  - Their procedural memories also remained intact - both could read, write, speak, and CW could still play the piano.

  - This evidence supports Tulving's view that there are different stores of LTM - one store can be damaged, but the others can remain unaffected.

  
  

  - Counterpoint: A major limitation of case studies is that they lack adequate controls.

  - For example, the injuries sustained by patients were often unexpected; the researcher had no way of controlling what happened to the participant before or during the injury. The researcher is therefore unable to know the individual's memory before the damage, making it difficult to judge how much worse it is after the injury.

  - This lack of control limits what studies can tell us about STM.
• Evaluating types of LTM: Conflicting neuroimaging evidence

  - A limitation is that there are conflicting research findings linking types of LTM.

  - Buckner and Peterson (1996) reviewed evidence about the locations of episodic and semantic memory. They found that semantic memory is located on the left prefrontal cortex, and episodic is on the right.

  - However, Tulving et al.'s (1994) research links the left PFC with episodic encoding, and the right PFC with episodic retrieval.

  - This challenges any neurophysiological evidence to support types of memory as there is poor agreement on where each type might be located.
• Evaluating types of LTM: Real-world application


  - A strength is that understanding types of LTM allows psychologists to help those with memory issues.

  - For example, as people age, they experience memory loss and this seems to be specific to episodic memories.

  - Belleville et al. (2006) created an intervention to improve episodic memory of older people. The trained participants performed better on a test of episodic memory after training than a control group.

  - This shows that distinguishing between types of LTM enables specific treatments to be developed.
• Evaluating types of LTM: Same or different?

  - In 2002, Tulving proposed that episodic memory is a specialised subcategory of semantic memory.

  - His research showed that some individuals with amnesia have a functioning semantic memory with a damaged episodic. He also concluded that it is impossible to have a functioning EM and damaged SM.

  - However, Hodges and Patterson (2007) found that some people with Alzheimers could form new episodic memories but not semantic memories.