Types of Long-Term Memory - Episodic, semantic, procedural Flashcards
Types of Long-Term Memory
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)
What is Episodic Memory
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.
Strengths of Episodic Memory
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.
Episodic memories have three elements:
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.
Episodic memories are associated with several areas of the brain:
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.
KEY STUDY: Tulving (1989)
Aim
To investigate possible differences in the processing of episodic & semantic memory tasks.
KEY STUDY: Tulving (1989)
Procedure
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.
KEY STUDY: Tulving (1989)
Findings
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.
KEY STUDY: Tulving (1989)
Conclusions
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.
KEY STUDY: Tulving (1989)
Evaluation
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).
:(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.
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.
:) 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.
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.
What is Semantic Memory
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.
Examples of semantic Memory
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
Semantic Memory
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.