long term memory

3 types of LTM

• episodic (1972)

• semantic (1989)

• procedural (1985)

• all coined by Tulving

episodic LTM definition

• LTM of events /experiences in our live

• Time-stamped, have to be consciously recalled

• Refers to autobiographical memory and storage of specific events or episodes which occurred in a particular time

evidence and results of episodic LTM

• Evidence that episodic memory is different to and separate from semantic memory comes from Tulving’s (1989) research in which he gave participants episodic and semantic memory tasks while observing regional cerebral blood flow

  • Blood flow to the cerebral indicates activity as it means more oxygen is getting to the cerebral cortex

  • Front of the brain was more active for episodic memory tasks

  • The back of the brain was more active during semantic memory tasks

  • This demonstrates that 2 types of LTM are being tested

semantic LTM definition

• Memory for the meanings of words or concepts

• Includes general world knowledge

• Semantic memory is though to be a type of explicit memory - that is memory we know we have, because we are consciously recollecting

procedural LTM definition

• Memory for skills, e.g.. How to ride a bike

• Hard to describe/explain these types of knowledge/memory

• Procedural memory is implicit, because it is not dependent on conscious recollection

• It is non-declarative, and you don’t necessarily know how you know it

evidence of procedural LTM

• Ryle (1949) underlined the distinction between episodic/semantic memory and procedural memory as being the difference between “knowing that and knowing how”

• Cohen (1984) who demonstrated that amnestic patients have impairment of semantic and episodic memory, but their procedural memory ability is intact

case study - Clive Wearing

• Wearing was a musician who contracted a virus which attacked his CNS

• As a result, he was unable to lay down new memories

• His hippocampus was damaged by the virus

• His STM only lasts for about 30s, but he is still able to play the piano

  • Wearing’s case study can be used to demonstrate the role the hippocampus plays in memory as after the hippocampus damage, he is unable to transfer memories from STM to LTM, also demonstrates that procedural memory is not formed in the STM

case study - Clive Wearing - methodological issues

• Because Clive had a brain injury, researchers who gather later evidence from him were not manipulating the IV

• This means that there is no record of what he was capable of before the brain damage

• It can also be hard to extrapolate data from patients like Clive Wearing to the general population with intact brains

research on Tulving’s LTM model

• Buckner and Peterson (1996)

  • Suggested that both semantic and episodic memory are located in the prefrontal cortex

  • Semantic memory is on the left side

  • Episodic memory is on the right

• Belleville et al. (2006)

  • Found that patients with mild cognitive impairment can improve their performance on episodic memory tasks after they have been given cognitive training