Memory lesson 4 - Types of LTM

Memory lesson 4 - Types of LTM

1. Episodic Memory

   • This kind of memory is concerned with your personal experiences
   • Linked to the word ‘episode’ an event or group of events relating to a larger sequence.
     • Your first day at school: this may include what happened who was there/ time and place.
   • There may also be links to context with this memory as well as associated emotions to the event
   • Specific details of the event
   • The context
   • The emotions

2. Semantic Memory

   • Not just that your first day of school was scary but that all children start school at 4/5 years old, or that 2 + 2 = 4
   • Semantic memories shared by others rather than personal knowledge that is found in episodic memory.
   • Semantic memories can relate to numerous things such as: functions of objects, appropriate behaviour, or abstract concepts such as maths or language.
   • Generally begin as Episodic memories as information is acquired on personal experiences.
   • Transition from episodic to semantic over time, memory loses its association with the episodic and can be generalised as semantic
     • Often strong recollection can remain as to where certain information is learnt.

3. Procedural Memory

   • This is concerned with skills – how to tie your shoe laces/ ride a bike/ how to dive/ how to read.
   • Knowing HOW to do something rather than why or the rules.
   • These memories are acquired through repetition and practice
     • Implicit memory – we are less aware of it.
       • Doesn’t require you to think about the step by step procedure as this can impede the ability to preform the task.
       • Necessary to allow us to perform other everyday tasks while carrying out procedural tasks

4. Evidence from brain scans

   • Different areas of the brain active when different LTM are accessed/active.
   • Episodic memory associated with the area that the hippocampus is located in - the temporal lobe.
   • Episodic memory also associated with the frontal lobe.
   • Semantic memory relies also on the temporal lobe
   • Procedural Memory is linked to the cerebellum
   • This area of the brain is linked to fine and gross motor skills with the motor cortex
   • The basal ganglia and the limbic system are also involved in this learning.

5. Case study HM

   • Man who was operated on to remove parts of hippocampus due to epilepsy (parts of temporal lobe also destroyed)
   • He retained pre-existing LTM
   • In depth study found that he could still form new procedural memories i.e. he learnt to draw a figure by looking at the reflection in a mirror (Corkin 2002- Mirror drawing)
     • He learnt the skill – procedural memory
       • But he could not remember learning (semantic/episodic memory)

6. Distinguishing between episodic and semantic memory

   • Studied looking at patients with Alzheimer's
   • Hodges and Paterson (2007)
     • Found that patients with Alzheimer's have been able to form new episodic memories but not semantic ones
     • Alone this is not sufficient proof of 2 distinct processes in the brain as semantic processing demands more of the brain and therefore brain damage will be likely to effect this process more
   • Irish et al (2011)
     • Found that patients with Alzheimer's had poor semantic memories but had good episodic memory
     • Suggested that episodic memory may be a gateway to semantic memory but they may be able to form separately

7. Priming

   • Research has shown that priming is controlled by a part of the brain separate from the temporal system
   • Temporal system supports explicit memory. (semantic and Episodic)
   • Belief that there is a 4th kind LTM
   • Perceptual-Representation System (PRS) –automatic enhanced recognition of specific stimuli
   • This is the effect of implicit memories and their influence on responses to a stimulus
   • Spiers et al (2001)
     • 147 patients with amnesia
     • All cases their procedural memories and their perceptual representation system (PRS) was intact
       • Their other 2 systems the episodic and semantic was not
     • This supported the idea that there are 2 types of implicit memory that were not affected by amnesia