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