Multi Store Memory Model

• Stages of memory:

  Encoding -> Storage -> Retrieval
• Multi Store Model:

  • 1968, Atkinson and Shiffon proposed a general framework for understanding memory
• Multi Store Model:

  Three unitary memory stores and the information is transferred between stores in a linear sequence. Each store varies in: Encoding (in what form), Capacity (how much) and Duration (how long)
• Multo Store Memory Model:

  
• Sensory Register:

  Responsible for briefly storing information from our senses before being processed by our brains. Sensory information is detected and recorded immediately
• Encoding:

  It depends on which sense organ the information comes from e/g vision = iconic memory, sound = echoic memory. It is modality specific
• The capacity if each sensory register is quite large but has a very short duration
• Sperlings (1960) - experimented into the duration and capacity of the sensory register (iconic store). Most of his subjects could only recall 4-5 out of the 12 letters in his first round and in his second, they could only recall 3 our of 4 letters per row.
• Information is stored in its raw form with multiple stores from different sensory inputs
• Short term memory:

  • STM capacity experiement was done by Jacobs in 1887
  • Called Digit Span Test
  • Found out STM can hold 7+/-2 items
• Chunking:

  • Miller - 1956
  • Found that the STM can hold 7+/-2 chunks (not items) of information
• STM duration:

  • Peterson and Peterson in 1959
  • Concluded that the duration of STM with no rehearsal is 18-30 seconds
  • Duration can be extended with verbal rehearsal
• Maintenance rehearsal usually involves repeating information without linking it to its meaning
• Encoding in STM is usually acoustic
• Long term memory:

  • Duration of LTM by Bahrick et al in 1975
  • 392 participants from Ohio aged 17-74. Used high school yearbooks to test photo recognition of 50 photos and free recall test where they recalled all the names of their graduation class
• Results of the yearbook test:

  • Photo recognition test = Within 15 years of graduation: 90% accurate. After 48 years: 70%
  • Free recall = Within 15 years: 60%. After 48 years: 30%
• LTM duration: Almost a lifetime
• LTM capacity: potential capacity is unlimited. Research unable to demonstrate a finite capacity
• LTM encoding: semantic (meaning)
• Information stored may last permanently and LTM may be unlimited in the amount of information it can contain. Information comes into LTM from STM via prolonged rehearsal. When using the information in LTM, it needs to be passed back to STM via retrieval.
• Sensory register:

  Capacity = large - Sterling (1960)

  Coding = modality specific

  Duration = short - Sterling (1960)
• Short term memory:

  Capacity = Small (7+/-2) - Jacobs digit span test (1887)

  Coding = Auditory

  Duration = Short - Peterson and Peterson (1959)
• Long term memory:

  Capacity = Large - Bahricks (1975)

  Coding = Semantic

  Duration = Very long - Bahricks (1975)
• HM Case:

  • supports the MSM as it shows that there are multiple memory stores
  • "He could not form new long-term memories but he performed well on tests of immediate memory span, a measure of STM"
• Counterpoint of HM Case:

  • clinical studies aren't perfect
  • Brain injuries were unexpected
  • Not representative
  • Researchers have no knowledge of the individual's memory before damage
  • Difficult to judge how much worse his memory was afterwards
• Baddeley's Test:

  Gave four lists of words = acoustically similar words, acoustically dissimilar words, semantically similar, semantically dissimilar
• Baddeley found that things using STM were harder to recall acoustically similar words while LTM found it harder to recall semantically similar words. This shows that STM and LTM are different stores.
• KF Case study:

  • evidence against the MSM as he had amnesia but found it easier to recall words that he had read to himself (iconic) than words that were read out to him (echoic/acoustic)
  • Challenges MSM as it suggests there is more than one STM store - visual and accoustic
• Craik and Watkins (1973):

  The type of rehearsal is more important than the amount. Elaborative rehearsal = links the information to your existing knowledge
• The MSM model also have limited relevance to everyday life.
• Tulving (1985) and others said that LTM involves different types of memory:

  • Episodic (events)
  • Semantic (Facts)
  • Procedural (How to do something)
• Episodic Memory:

  • time-stamped = when and what happened
  • includes several elements = people, places, feelings, behaviours...
  • effort needed when recalling = search memory for what happened
• Semantic memory:

  • shared knowledge of the world
  • not time-stamped
  • less personal and more about facts we share, no emotions involved
  • consantly being added to
• Procedral memory:

  • Memory for actions or motor skills/muscles
  • muscle based memory
  • can be recalled without conscious or much effort
  • hard to explain/unavailible to conscious inspection
  • becomes automatic through practise
  • more resistant to forgetting/amnesia
• Clive Wearing Case:

  Had amnesia. Strength of types of memory.

  • relatively unaffected semantic memory = remembered meaning of words
  • severely damaged episodic memory = couldn't remember events like when he last saw his life
  • Unaffected procedural memory = could remember how to play the piano
• Elderly people:

  Strength of types of LTM.

  • Experience memory loss
  • Research shows its specific to episodic
  • Devised intervention to improve episodic memory
  • Participants performed better after training

  Distinguishing between types of LTM enables specific treatment.
• Research:

  Strength of types of LTM.

  • linked types of LTM to the brain
  • Episodic = hippocampus/right prefrontal cortex
  • Semantic = left prefrontal cortex, frontal/temporal lobes