Models of Memory

Models of Memory

1. Atkinson and Shiffrin (1968) - Multistore Model of Memory: this model proposed there are 3 stores; sensory register-short term-long term. Info constantly going to sensory register, if you focus on it it will go to short term memory. Short term memory has a finite capacity and duration, if info is rehearsed then it can be transferred to LTM (in theory info can stay there forever)

   • Primacy Effect: research shows that people can recall beginning of list better than middle. supports MMM because earlier items would have had more rehearsal and been transferred to LTM. if rehearsal prevented by interference task then primacy effect disappears.
   • Recency Effect: STM has capacity of 7, if not rehearsed words in the middle of list are displaced by those most recently heard. These words are still in STM at end of experiment when they need to be recalled.
   • Korsakoff's syndrome: LTM damaged by alcoholism, they can recall last few items on a list (recency effect unimpaired) suggests an undamaged STM, LTM however is poor which provides support for seperate stores
   • Milner (1957) - case study of patient called HM who had severe epilepsy, seizures can from hippocampus; doctors lesioned a portion of this which reduced epilepsy but led to memory loss. could still form short term memories but could not form long term ones, evidence for separate stores.
   • in this model rehearsal is necessary for transfer into LTM; however memories get transferred into LTM without rehearsal. also smells cannot be rehearsed however they transfer to LTM.
   • Oversimplified, assumes there is only one long and one short term store; this has been disproven by brain damage patients which suggests there are multiple stores of both

2. Baddeley and Hitch (1974) - developed the working memory model in which STM is an active processor with multiple stores. Central Executive - it is attention, has a limited capacity and controls slave systems. Phonological Loop - speech based info, made up of phonological store and articulatory process (inner voice). Visuospatial sketchpad - deals with temporary storage of visual and spatial info. Episodic Buffer - (added in 2000) briefly stores info from other systems (including LTM) to make complete episodes.

   • Baddeley and Hitch built this model around interference tasks. any two tasks that use the same sub-system e.g. saying "the" repeatedly whilst trying to read will interfere with one another. if they use two different systems then performance on either task isn't affected.
   • Shallice and Warrington (1974) - case study of patient called KF with brain damage, impaired STM in which he could not recall words presented verbally but could recall them if presented visually. this suggests and intact visuospatial sketchpad but impaired articulatory loop. provides evidence for Working Memory Model, could not have been explained by multistore model
   • Gathercole and Baddeley (1993) - 2 conditions, indépendant groups. first condition had to follow moving light whilst describing the angles on a letter (both used visuospatial sketchpad). other condition had to follow moving light whilst doing a verbal task (using phonological loop and VSSP). found performance was much better in second condition.
   • Simplistic and Vague as doesn't explain what central executive fully is, hard to test central executive
   • only explains how info is dealt with in short term memory, doesn't explain how it gets to LTM
   • much of supporting evidence has been lab studies which have low ecological validity, not representative of way memory works in everyday life