Types of LTM

Why did Tulving (1985) propose that there were different types of LTM?

He believed the MSM’s view of LTM was too simplistic and inflexible

What are the three different types of LTM?

• Episodic memory

• Semantic memory

• Procedural memory

What is episodic memory?

Our ability to recall events (episodes) from our lives

Are episodic memories time-stamped?

Yes

Are episodic memories unconscious or conscious?

Conscious effort is required to recall events - it is very fast but you are still aware of it

What is semantic memory?

Our shared knowledge of the world - often compared to an encyclopaedia

Are semantic memories time-stamped?

No

Is semantic memory conscious or unconscious?

Conscious

What does Tulving say that semantic memory has that episodic doesn’t?

It is less vulnerable to distortion and forgetting like episodic memory

What is procedural memory?

Memory of actions or skills

Is procedural memory conscious or unconscious?

Unconscious

What does it mean that procedural memory is more ‘practical’?

They are hard to explain in words, and easier to show physically

What condition did Clive Wearing have?

Encephalitis - brain damage in the left, right and frontal lobes, and the hippocampus

How did Wearing catch encephalitis?

• In his 40s, he developed a bad headache, which developed into a fever

• After 5 days, he forgot his daughter’s name

How did encephalitis affect Wearing’s memory?

• His episodic memory was effected, but not his procedural memory → still very intelligent

• He remembered some things before the infection, such as his wife.

• His STM was damaged - as soon as his brain received information, it would fade after a matter of minutes - moment-to-moment consciousness

How did encephalitis affect Wearing’s behaviour?

• He greeted his wife as if he hadn’t seen her in a long time, even if she’d been gone for a few minutes

• Very emotional - angry and frustrated as he knew he had done things that he couldn’t remember

• He kept a diary and wrote every time he remembered something - he would cross out previous entries as he didn’t remember writing them

What are the strengths of the Wearing’s case study?

• Highly descriptive - rich data

• High ecological validity - real-life behaviour

• Stimulates further research

• Ethical

What are the limitations of the Wearing’s case study?

• Lack of control over Wearing’s behaviour

• Impossible to replicate

• Lack of generalisability

• Risk of bias due to nature of a case study

How did Henry Molaison develop profound amnesia?

• Suffered from epilepsy as a child

• Constant, intense seizures disrupted everyday life

• Underwent brain surgery in 1953 → tissue was taken out of his brain

How did profound amnesia affect HM’s memory?

• Unable to remember anything that happened after the operation

• He would often repeat the same thing multiple times within one conversation without knowing

How did profound amnesia affect HM’s behaviour?

• Unable to care for himself as he couldn’t make any new memories

• Never afraid of anyone even though he couldn’t remember who they were

• Remained cheerful and wanted to give as much info as possible to psychologists and neurologists

What are the strengths of Tulving’s theory?

• Clinical evidence

• Research support

• Real-world application

What are the limitations of Tulving’s theory?

• Clinical evidence may not be reliable

• Conflicting research findings

• Episodic and semantic memory may not be separate

What clinical evidence is there to support Tulving’s theory?

• Cases of HM + Clive Wearing: both suffered damage to their episodic memory, but their semantic and procedural memories still worked

• Suggests there are different types of LTM, some can be damaged whilst others remain intact

What research support is there for Tulving's theory?

Hodges & Patterson (2007) found some people with Alzheimer’s could form new episodic memories but not semantic → shows that stores could be separate

How does Tulving’s theory have real-world application?

• Research has shown memory loss is specific to episodic memory in aging people.

• Belleville et al. (2006) trained older participants to perform better on an episodic memory test. They performed better than the control group without training.

Why may the clinical evidence may not be reliable?

• Clinical studies lack control over variables → behaviour of the participants, what happened before and during the injury, and no full knowledge of how the memory has worsened.

• Lack of control limits how much clinical studies can tell us about LTM

How have there been conflicting research findings?

• Buckner & Petersen (1996) concluded semantic memory is located in the left side of the prefrontal cortex and episodic memory on the right.

• Tulving et al. (1994) links the left prefrontal cortex with encoding episodic memories and the right with episodic retrieval.

• Challenges any neurophysiological evidence to support types of memory as there is lack of agreement on location

How did Tulving disprove himself?

• Tulving (2002) concluded episodic memory is a ‘specialised subcategory’ of semantic memory.

• His research shows that some people with amnesia have both a damaged semantic and episodic memory.

• Therefore it is not possible to have a functioning episodic memory with damaged semantic memory