MULTISTORE MODEL OF MEMORY

Atkinson + Shiffrin

SUPPORTING EVIDENCE FOR STM + LTM BEING DIFFERENT STORES

  • A structural model which includes 3 separate stores
  • Information passes between stores in a linear way
  • Proposed the multi store memory model

Three separate stores

Short term memory (STM)

Long term memory (LTM)

Sensory memory (SM)

  • Includes several stores called sensory registers (SR)
  • Each SR processes information from a particular sense
  • Iconic register : processes vision
  • Echoic register: processes sound
  • Haptic register: processes touch
  • The SR is not under cognitive control + is the first storage system for incoming information
  • Information received is raw + unprocessed
  • The SR has a large capacity
  • Duration = milliseconds unless given focused attention in which case it will then move to the STM
  • Rehearsal maintains information in the STM
  • But it is still vulnerable to being forgotten due to limited duration (decay)or being displaced by new incoming information due to limited capacity (displacement)
  • If rehearsed + processed deep enough through elaborative or maintenance rehearsal information then passes to the LTM store
  • STM encoding = acoustic with a capacity of 7+/-2 items
  • Duration = up to 18 seconds
  • Unlimited capacity
  • Unlimited duration dependent on the level or processing of the information received
  • LTM coding is mainly semantic + based on meaning

EASILY TESTED TO VERIFY WHETHER IT APPLIES TO HUMAN BEHAVIOUR

SOME RESEARCH INTO STM DURATION HAS LOW ECOLOGICAL VALIDITY

OVERSIMPLIFIED MEMORYY STRUCTURES + PROCESSES - SHALLICE ET AL

  • Glanzer et al - participants were tasked with recalling word lists with earlier + later words more likely to be recalled
  • This was known as the primacy + recency effect
  • This primacy effect occurs as the first words are transferred to LTM
  • Recency effect occurs as the last words are still within the STM
  • Delays of 10 seconds or more before recall resulted in only a primacy effect with inly LTM effected
  • This highlights the difference between STM + LTM which supports the MSM theory
  • The evidence supports the idea of STM + LTM being separate types of memory + it has been verified through the use of PET scans and FMRI scans when participants have been doing separate tasks related to STM + LTM
  • Prefrontal cortex = related to STM
  • Hippocampus = related to LTM
  • This supports the models idea of different memory stores
  • KF case study - patient who suffered brain damage which resulted in difficulty with verbal information in STM but normal ability with visual information
  • This highlights how STM is not a single store as the MSM
  • LTM may not be a single store either as Schachter et al proposed 4 different types of LTM stores; Semantic, Episodic, Procedural
  • Semantic: memory for knowledge
  • Episodic: memory of your own actions/what you did
  • Procedural: such as riding a bike or learning to read
    Perceptual-representation: PRS - memory related to recognition of specific stimuli
  • The stimuli that participants were trying to remember bear little resemblance to items learned in real life
  • E.g. nonsense trigrams like 'XQF' were being used to determine the duration of their STM
  • As the participants would never do this outside of a controlled environment, it is difficult to generalise the results to real life as we are unsure that they would react in the same way so results may be different