working memory model

• Baddeley and Hitch (1974)


  A version (model) of STM which sees this store as non-unitary and an active processor.

  
• central executive

  • controls/ oversees the whole system and designates tasks to the sub-systems
  • sends auditory information to the phonological loop and visual information to the visuo-spatial sketchpad for processing
  • has a limited capacity
  • allocates limited attention to tasks by focusing on one task or dividing it between the sub systems
• visuo-spatial sketchpad

  • controlled by central executive
  • inner eye- processes visual information
  • stores visual data (images and information about shape and colour)
  • visual cache manipulates/ arranges images in the visual field (inner scribe)
  • limited capacity (3-4 objects)
• episodic buffer

  • integrates/ synthesises information from other stores
  • serves as a temporary storage system to the inter-connect information from each system and provides the main link to LTM
  • maintains the sequencing
  • modality free- can process any type of information
  • added to the model in 2000
  • limited capacity of around 4 items
• phonological loop

  • sub system controlled by the central executive
  • consists of the articulatory loop (inner voice) and primary acoustic store (inner ear)
  • Inner ear processes and stores auditory/ sound based information (stores according to tone, volume, pitch etc).
  • articulatory loop (inner voice)- inner rehearsal loop, sub vocal speech (keeps words until you say them in working memory)
  • phonological loop is limited in capacity and has temporary storage (1-2 seconds)
• Shallice and Warrington (1970)

  • KF brain damage due to a motorcycle accident
  • KF could not remember words read to him (verbal/ auditory information) but could if he read them himself (visual information)
  • phonological loop was damaged, but his VSSP was intact
  • supporting STM has separate components otherwise both verbal and visual memory would be impaired
  • evidence from brain-damaged patients may not be reliable because it concerns unique cases
• Paulesu et al (1993)

  • participants were asked to:
  • memorise a series of letters
  • or mentally rehearse the sounds of the letters
  • blood flow was monitored using PET scans
  • mental rehearsal of sounds showed increased blood flow (activity) in the Brocos area, whereas when memorising a series of letters, wernickes area was active.
  • evidence the phonological loop has two components.
• Hitch and Baddeley (1976)

  • participants completed a verbal reasoning task (B is followed by A and where shown BA and had to say if this was true or false. This task uses central executive)
  • At the same time, participants had to do one of four things:
  • say "the" repeatedly
  • say the sequence "1,2,3,4,5,6" over and over again
  • repeat a random string of digits aloud every trial
  • or there was no additional task
  • saying "the" or "1,2,3,4,5,6" repeatedly would use the articulatory loop. Saying random digits uses central executive.
  • Reasoning performance was slower in the random digits condition. (dual task- both random digits and verbal reasoning task uses the central executive)
• Baddeley et al (1975)

  • participants were given lists of short (e.g. cat) or long (e.g. university) words to recall
  • they recalled more of the short words
  • the phonological loop can hold the number of items that can be said in about 2 seconds (shorter words can be rehearsed more times)
• evaluation 1

  P one limitation of the working memory model is the role of the central executive is not well explained

  E baddeley (2003) 'the central executive is the most important but the least understood component of working memory'

  E evidence suggests that the central executive is not unitary and may consist of separate components. Eslinger and Damasio (1985) EVR had a tumour removed. He performed well on tests requiring reasoning, which suggests that his central executive was intact; however, he had poor decision making skills (he would spend hours trying to decide where to eat.) This suggests that the central executive was not wholly intact. EVR had good reasoning skills but was poor at decision making.

  L the central executive may consist of separate components. Little research has been done into the episodic buffer
• evaluation 2

  P the working memory model is supported by highly controlled lab studies which may undermine the validity of the model

  E dual-task studies support the working memory model because two tasks that use the same sub system are harder to perform together than tasks that involve separate components

  E there must be separate components in working memory.

  L these studies use tasks that are not like tasks we perform in everyday life and are carried out in highly controlled laboratory conditions, so do not reflect how working memory works in real life
• evaluation 3

  P the working memory model has practical application e.g. phonological deficits observed in dyslexia are linked to articulatory loop deficits

  E Gathercole and Baddeley (1990) children with dyslexia and ADHD had an impaired memory span and difficulty saying whether words rhymed suggesting a phonological loop deficit

  E this has led to practical applications in helping children to read and help children with ADHD focus on tasks e.g. use brief and simple instructions so they dont forget what they are doing (limited capacity of phonological loop)

  L the working memory model has benefits. Practical application of the multi store model are limited. The working memory model attempts to explain how memory functions, as opposed to simply describing the structure of memory
• evaluation 4

  P research supports separate systems for visual and spatial information in the VSSP

  E people who are blind from birth have no visual awareness of their environment but have spatial awareness supporting two separate systems in the visuo-spatial sketchpad

  E Smith and Jonides (1997) found when participants took part in a spatial task there was more activity in the right hemisphere and more activity in the left when they were doing a visual task

  L VSSP may consist of more than one component. one that deals with visual and one that deals with spatial information