Types of Long-Term Memory - Episodic, semantic, procedural

Question 1

Types of Long-Term Memory

Answer 1

Research indicates the existence of different types of long-term memory, each with a different function and a different area of the brain associated with its use.
The main subdivision of LTM is into explicit and implicit:
(LOOK AT DIAGRAM)

Question 2

What is Episodic Memory

Answer 2

This type of memory relates to events.
It is an explicit type of memory (available for conscious inspection and can be expressed verbally).
It provides us with an autobiographical record of our personal experiences.

Question 3

Strengths of Episodic Memory

Answer 3

The strength of episodic memories is influenced by the emotions present at the time a memory is coded, for example, traumatic events are often recalled well due to their high emotional content.

Question 4

Episodic memories have three elements:

Answer 4

Specific details of the event
The context of the event i.e. where you were
The emotions experienced at the time

The strength of these memories is also influenced by the degree of processing of information at coding - highly processed episodic events are recalled more easily.
It is thought that this type of memory helps individuals to distinguish the difference between real and imagined events.

Question 5

Episodic memories are associated with several areas of the brain:

Answer 5

The prefrontal cortex is associated with the initial coding of episodic memories.
Consolidation (strengthening) of these memories is associated with the neocortex.
Memories of different parts of an event are located in the different visual, auditory, olfactory etc. areas of the brain, but are connected together in the hippocampus to create a memory of an episode, rather than it remaining a collection of separate sensory memories.

Question 6

KEY STUDY: Tulving (1989)
Aim

Answer 6

To investigate possible differences in the processing of episodic & semantic memory tasks.

Question 7

KEY STUDY: Tulving (1989)
Procedure

Answer 7

6 volunteers were injected with a small amount of radioactive gold, which was scanned to detect its location with a gamma ray detector. Tulving was one of the participants, along with his wife and a colleague.
Each participant performed 8 successive trials, each lasting 80 seconds, involving 4 semantic and 4 episodic topics in randomised order.
Individual trials were separated by 2 minutes of rest each. A participant would lie on a couch with their eyes closed and indulge in either episodic or semantic LTM retrieval. The retrievals involved silent mental thought. Participants selected what topics they would think about: episodic ones involved personally experienced events, like a holiday, and semantic ones involving general knowledge acquired through learning, like by reading a book.
At a signal from a researcher, a participant would begin thinking about a topic, the gold being injected in after 60 seconds and the scanning occurring about 8 seconds later, after the gold tracer had arrived in the brain.

Question 8

KEY STUDY: Tulving (1989)
Findings

Answer 8

3 participants produced inconclusive data.
Data from the other 3 participants showed consistent differences in cortical blood flow patterns between semantic and episodic thinking.
There was greater activation in the frontal lobes (anterior regions) of the cortex during thinking about episodic memories and greater activation in the posterior region of the cortex when retrieving semantic information.

Question 9

KEY STUDY: Tulving (1989)
Conclusions

Answer 9

Episodic and semantic LTM’s appear to involve different brain areas and thus are separate forms of LTM.
The involvement of different brain areas suggests a biological basis to differences in LTM.

Question 10

KEY STUDY: Tulving (1989)
Evaluation

Answer 10

As only 3 out of 6 participants showed differences between processing of episodic and semantic LTMs, the findings cannot be seen as generalisable to the population as a whole.
As Tulving himself was one of the participants, plus his wife and another colleague, it may have been difficult to conduct the study and analyse the findings in an unbiased, objective manner (see other points on page 70).

Question 11

:(The extent to which episodic and semantic memory systems differ is unclear - although different brain areas are involved, there is also a lot of overlap between the two systems.

Answer 11

Semantic memories often clearly originate in episodic memory (e.g. your memory of being taught something is episodic, but what you learned may be semantic).
It may be the case that an episodic memory can transform into a semantic memory; however, we cannot be certain whether this is what occurs.

Question 12

:) How does Tulving’s research support the existence of episodic memory?
P: Tulving’s research provides support for the existence of episodic memory as separate to other forms of long-term memory.

Answer 12

E: 6 participants were asked to indulge in episodic LTM retrieval for a series of 4 trials, each lasting 80 seconds. Each participant was injected with a small amount of radioactive gold, which was scanned to detect its location in the brain. Tulving found that during this task, there was activation in the [anterior regions of the] frontal lobe.
C: This therefore suggests that episodic and semantic LTM’s involve different brain areas and thus are separate forms of LTM. This suggests a biological basis to differences in LTM.

:)Research often uses advanced scientific techniques such as brain scans - why is this a strength?
Neuroimaging objectively studies and measures cognitive processes within live participants.

Question 13

What is Semantic Memory

Answer 13

This type of memory is also explicit and contains all knowledge and facts that an individual has learned.
Semantic memories may relate to things e.g. the functions of objects; knowing what behaviour is appropriate e.g. social customs; and may relate to abstract concepts e.g. maths and language.

Question 14

Examples of semantic Memory

Answer 14

Knowing the names of capital cities
Knowing how to spell certain words
Knowing that a lion is a mammal
Knowing the elements of H₂O
Knowing that football is a sport
Knowing who the Prime Minister is
Knowing that an apple is a fruit

Question 15

Semantic Memory

Answer 15

The strength of semantic memories is positively associated with the degree of processing occurring during coding.
They often appear to be underpinned by episodic memories, as there is an episodic memory of when the memory was acquired (the experience of learning it).
Over time there appears to be a gradual shift of episodic memories transitioning to eventually become semantic memories, with the knowledge/understanding becoming more divorced from the event or experience it was learned from.

Question 16

There is disagreement over the parts of the brain associated with semantic memory.

Answer 16

It seems that the hippocampus is involved, but evidence also suggests the involvement of several other parts of the brain, coding is mainly associated with the frontal and temporal lobes.

Question 17

Semantic Memory
Vicari et al. (2007)

Answer 17

Vicari et al. (2007) conducted a case study of an 8 year old girl. She suffered brain damage due to the removal of a tumour.
She experienced problems with her episodic LTM, especially in creating new episodic memories, but was still able to create and recall semantic memories.
This study suggests that episodic and semantic memory are separate systems using different brain areas, with the hippocampus associated with episodic memory and the perirhinal cortex with semantic LTM.

Therefore, it may be the case that semantic memory is not a single type of memory….
This case study suggests that semantic memory involves a network of associated links spread throughout different brain areas and structures, rather than being a single form of memory.

Question 18

Semantic Memory Evaluation

Answer 18

 As is the case with the evaluation of episodic memory - there is some debate about the difference/overlap between semantic and episodic memory. Research suggests that episodic memories may be a gateway to semantic memory, but it is possible for semantic memories to form separately.

It may be that episodic memory differs from that of semantic memory in terms of different types of thinking and emotion:
Episodic memories are associated with conscious awareness of events and emotional feelings related to them.
Semantic memories are associated with objective analysis of phenomena.

Question 19

What is Procedural Memory

Answer 19

Procedural memory is memory for motor skills/actions/’muscle memory’.
This type of memory is a form of implicit memory in that it permits individuals to perform learned tasks with little conscious thought (enabling people to simultaneously perform other cognitive tasks that require attention e.g. you can walk and hold a conversation at the same time).
Procedural memories are difficult to explain in words.
Many procedural memories occur early in life, acquired through repetition and practice.

Question 20

Examples of Procedural Memory

Answer 20

Riding a bicycle
Walking
Getting dressed
Speaking
Tying shoelaces
Swimming
Driving
Playing football

Question 21

Areas of the brain associated with procedural memory

Answer 21

Procedural LTM is involved in language, helping individuals to speak automatically, using grammar and syntax without having to think about how to. This suggests that procedural and semantic memories are likely to work together.
Procedural memory is mainly associated with the motor cortex, cerebellum and prefrontal cortex.
Unlike the explicit forms of LTM, procedural memory does not require the hippocampus to function.

Question 22

Evaluating Procedural Memory

Answer 22

The case of Clive Wearing
Clive Wearing was unable to lay down any new episodic or semantic long-term memories, after his hippocampus was destroyed by a viral infection.
However, Clive was still able to sight-read and play complex pieces on the piano, suggesting that his procedural memory was intact.

This supports the distinction between procedural LTM and other types of LTM, because if procedural memory was linked to episodic and semantic memory, then Clive would be unable to create new memories for skills.

Question 23

Evaluating Procedural Memory
The case of H.M.

Answer 23

The case study of H.M. provides support for procedural memory - his ability to form new LTM’s was severely affected by the destruction of his hippocampus and parts of the temporal lobes, although he appeared unable to form new explicit (declarative) memories, he retained the ability to form new procedural memories.
This was demonstrated by his ability to learn mirror drawing (e.g. tracing a star shape while looking at his hand in a mirror).
His performance improved over 3 days (10 trials/day) despite the fact that he could not consciously remember having done the task before on days 2 and 3.

Question 24

:(However, there is a general lack of research that can demonstrate which areas of the brain are associated with procedural memory.

Answer 24

This is because one of the main ways we can establish this is through the study of patients with brain damage who exhibit impairment in their procedural memories.
These patients are very rare and as such it is still unclear exactly which regions of the brain are involved.