TYPES OF LONG-TERM MEMORY

~EPISODIC MEMORY~

  • Refers to our ability to recall events (episodes) from our lives - these memories are complex

  • These memories are ‘time-stamped’ - you remember when they happened as well as what happened

  • The memory will include several elements, such as people, places and objects - these are all interwoven to produce a single memory

  • Have to make a conscious effort to recall episodic memories - happens quickly, but you’re still aware that you’re searching for it

~SEMANTIC MEMORY~

  • Includes our shared knowledge of the world

  • Contains your knowledge of concepts such as ‘animals’ and ‘love’

  • These memories are not time-stamped

  • Semantic knowledge is less personal and more factual

  • Less vulnerable to distortion and forgetting than episodic memory

~PROCEDURAL MEMORY~

  • Memory for actions or skills

  • Memories can be recalled without conscious awareness or much effort (eventually) (e.g. driving a car)

  • May find these skills hard to explain to someone else

EVALUATION

Research Support

→ CLINICAL EVIDENCE

  • One strength is evidence from the case studies of HM.

  • His episodic memory was severely impaired due to brain damage, but his semantic memory was relatively unaffected.

  • For example, HM could not recall stroking a dog half an hour earlier, but he understood the concept of ‘dog’. His procedural memory was also intact, as he could still walk and talk.

  • This supports Tulving’s view that there are different memory stores in LTM - one store can be damaged while others remain unaffected.

  • However, clinical studies are not perfect. A major limitation is that they lack control of extraneous variables.

  • The brain injuries experienced by participants were unexpected and so researchers had no control over what happened to the participants before or after the injury. 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.

→ REAL-WORLD APPLICATION

  • Another strength is that understanding types of LTM allows psychologists to help people with memory problems.

  • For example, as people age, they experience memory loss. But research has shown that it seems to be specific to episodic memory - it becomes harder to recall memories of personal experiences that occurred recently, though past episodic memory remains intact.

  • Psychologists devised an intervention to improve episodic memories in older people. The trained participants performed better if 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.

Conflicting Evidence

→ CONFLICTING NEUROIMAGING EVIDENCE

  • One limitation is that there are conflicting research findings linking types of LTM to areas of the brain.

  • For example, psychologists reviewed evidence regarding the location of semantic and episodic memory.

  • They concluded that the semantic memory is located in the left side of the prefrontal cortex, and episodic memory is on the right. However, other research shows it to be the other way around.

  • This challenges any neurophysiological evidence to support types of memory as there is poor agreement on where each type might be located.