Multi store memory model

Multi store memory model

• Proposed by Atkinson and Shiffrin in 1968 

• The model is composed of the sensory memory store, short-term memory store and long-term memory store 

• Suggested that memory is store in 3 locations 

Sensory memory

• temporary store holding information from the environment very briefly through visual, auditory, tactile or olfactory.  

• When we pay attention, the stimuli, which is the information, pass through sensory memory to the STM store 

STM

• limited in both capacity and duration. 

• The capacity of short-term memory store is assumed to be limited to around 7 items (+/- 2) and its duration is about 6-18 seconds → it is quickly lost if not rehearsed 

• The information is either held until it is displaced from STM by new information, when your attention is taken away or moved to the LTM store if we rehearse it

LTM

• LTM has an indefinite duration and potentially unlimited capacity 

• When we recall information, we retrieve it from LTM and move it back to STM

Milner - Outline/ Explain the multi store model of memory

• Aim: Case study of the function of the hippocampus in memory formation 

• Background information : 

  • Patient HM suffered a serious head injury at age 7 

  • Underwent experimental surgery where his hippocampus were removed to treat his seizures.

  • Following surgery, HM suffered from anterograde amnesia—he could no longer transfer new information from short-term to long-term memory—while his earlier memories and intellectual abilities remained largely intact.

• Procedure:

  • Longitudinal case study that lasted for over 50 years to understand the cognitive effects of the surgery.

  • Method triangulation. 

    • Psychometric testing where IQ test is given→ measures general intellectual functioning. 

    • Direct observation of his behaviour in a naturalistic setting along with interviews with both HM and family members 

    • Cognitive testing, including memory recall tests and learning tasks such as reverse mirror drawing, which access procedural memory 

    • Later did an MRI to determine the extent of damage

Findings

• Results: 

  • Hm could not acquire new episodic(event) knowledge and new semantic( about the world) knowledge. Suggests that hippocampus are important for transfer of information from STM to LTM. 

  • HM had a capacity for working memory - able to carry on a normal conversation. 

  • Procedural memory was well maintained - showed improvements in reverse mirror drawing.

Conclusion

The hippocampus plays a critical role in the transfer of memory.

Link

• This study supports MSM by providing evidence for the existence of separate STM and LTM models through the clear dissociation between HM's ability to hold information temporarily STM and his inability to store it permanently LTM

• showing one store could be damaged while the other remained relectively unaffected.