Types of Long-Term Memory

Types of Long-Term Memory

1. LTM memory part 1

   • divided into 2 types explicit (declarative - knowing that) and implicit (procedural - knowing how)
   • episodic
     • memories declarative & occur as a part of a sequence
     • concerned with personal experience
   • Semantic
     • declarative
     • knowledge about the world which is shared by everyone - rather than episodic 'personal experience'
   • Procedural
     • concerned with skills e.g. how to tie a shoelace or swim

2. LTM memory part 2

   • episodic
     • might be memory of family holiday
     • three elements: details of the event, the context & the emotions felt
   • Semantic
     • related to things, such as functions of objects, or what behaviours is appropriate in a particular situation
     • also related to abstract concepts e.g. maths & language
   • Procedural
     • acquired through repetition & practice
     • less aware of these as automatic e.g. how to ride a bike

3. Evaluation

   • Supporting brain scans
     • research shows different areas of the brain are active when using different types of LTM
     • episodic memory is associated with the hippocampus & temporal love, semantic memory relies on the temporal love also & procedural memory is associated with the cerebellum
     • suggests three types of long term memory are separate & found in different areas of the brain
   • Case studies
     • case of patient HM highlights the distinction between procedural & declarative memories. Surgery, patient HM could still form new procedural memories but he was unable to form episodic/semantic
     • e.g. patient HM was able to draw figure by looking at its reflection in a mirror, a skill called mirror drawing (procedural memory), however, he could not remember learning this skill (episodic/semantic memory)
     • supports distinction of procedural & episodic/semantic memories, as different types of long term memory highlighting the existence of multiple types of long term memory
   • patients with Alzheimer's
     • Hodges & Patterson (2007) found that some patients with Alzheimer's disease retain the ability to form new episodic memories but not semantic memories
     • Furthermore, Irish et al (2001) the reverse in Alzheimer's patients, who had poor semantic memories but generally intact episodic memories
     • double-disassociation suggests that episodic & semantic memories are separate & that episodic memories may be gateway to semantic memory, but it is possible for semantic memories to form separately.
   • use of patients with brain damage
     • difficult to conclude from case of HM the exact parts of brain that were affected
     • damage to a particular area doesn't mean this area is responsible for particular behaviour
     • unable to conclude a casual relationship between a particular brain region & type of LTM
   • fourth type of LTM
     • research investigating priming describes how implicit memories influence the response a person makes
     • Priming is controlled by a brain system separate from the temporal system that supports explicit (semantic & episodic) which has led to the suggestion that there is a fourth type of LTM
     • suggests that the original theory of LTM is too simplistic & other types may exist