Types of long-term memory

Who was Tulving?

One of the first cognitive psychologists to realise that the MSMs view of LTM was too simplistic and inflexible.

What did Tulving propose?

There are 3 LTM stores containing different info.

What are the 3 LTM stores?

Episodic memory

Semantic memory

Procedural memory

What is episodic memory?

• LTM store for personal events.

• Includes memories of when events occurred and the people, objects, places and behaviours involved

• E.g. your last birthday party

• The elements are interwoven to produce a single memory which is very complex.

• Time stamped

• Memories from this store have to be retrieved consciously and with effort.

• Declarative

What is semantic memory?

• LTM store for our knowledge of the world

• Includes facts of our knowledge of what words and concepts mean

• Constantly being added to

• Less vulnerable to distortion and forgetting than procedural

• NOT time stamped

• Memories from this store have to be retrieved consciously and with effort

• Declarative

What is procedural memory?

• LTM store for our knowledge of how to do things

• Includes memories of learned skills

• E.g. driving a car

• NOT time stamped

• Memories DO NOT have to be retrieved consciously or with effort

• Non declarative

What is a strength of the types of LTM? (HM and Clive Wearing)

Evidence from the case study of HM and Clive Wearing

Episodic memory in both men was severely impaired due to brain damage but their semantic and procedural memories were unaffected. For example, HM could not recall stroking a dog a half and hour earlier but did not forget the concept of a ’dog’. Clive Wearing knew how to read music, sing and play the piano.

This supports Tulving view that there are different memory stores in LTM - one store can be damaged but other stores are unaffected.

What is a limitation of the types of LTM? (Buckner and Peterson)

There are conflicting research findings linking types of LTM to areas of the brain.

Buckner and Petersen reviewed evidence regarding the location of semantic and episodic memory. They concluded that semantic memory is located in the left side of the prefrontal cortex and episodic memory on the right.

However, Tulving links the left prefrontal cortex with encoding of episodic memories and right 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.

What is a strength of the types of LTM? (Belleville et al)

Understanding types of LTM allows psychologists to help people with memory problems.

E.g. as people age, they experience memory loss. But research shows that this is specific to episodic memory.

Belleville et al devised an intervention to improve episodic memories in 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.

What is a limitation of the types of LTM? (lack control variables)

Lack control of variables

Studying people with brain injuries can help researchers understand how memory is supposed to work normally. But they lack control of variables. The brain injuries experienced by participants were unexpected. The researcher has no knowledge of the individual’s memory before the damage, Without this, it is difficult to judge exactly how much worse it is afterwards.

This lack of control limits what clinical studies can tell us about different types of LTM.