The working memory model

• who developed the working memory model?

  baddeley and hitch
• what is WMM a model of?

  short-term memory.
• WMM is an explanation of how STM is organised and how it functions.

  for example, WMM is concerned with the part of the mind that is active when working on an arithmetic problem or playing chess or comprehending language, etc.
• what are the four elements of the WMM?

  central executive, phonological loop, visuo-spatial sketchpad and the episodic buffer.
• central executive

  essentially an attentional process which monitors incoming data and allocates slave systems to tasks.

  it has a very limited storage capacity.
• phonological loop

  deals with auditory information and preserves the order in which the information arrives. subdivided intoL phonological store and articulatory process.
• phonological store

  stores the words you hear.
• articulatory process

  allows maintenance rehearsal (repeating sounds to keep them in WM while they are needed).
• visuo-spatial sketchpad

  stores visual and/or spatial information when required (e.g. recalling how many windows your house has).

  logie subdivided the VSS into: the visual cache and inner scribe.
• visual cache

  stores visual data.
• inner scribe

  records arrangement of objects in visual field.
• episodic buffer (EB)

  added in 2000. it isn a temporary store for information.

  integrates visual, spatial and verbal information from other stores.

  maintains sense of time sequencing- recording events (episodes) that are happening.

  links to LTM.
• strength of the WMM: case of KF supports separate STM stores

  shallice and warrington carried out a case study of patient KF who had brain damage. he had poor STM ability for verbal information normally (difficulty with sounds but could recall digits/letters). so his phonological loop had been damaged but other areas of memory were intact. this suggests there are separate visual and acoustic stores. however, evidence from brain-damaged patients may be unreliable because it concerns unique cases of patients who have had traumatic experiences.
• limitation of the WMM: lack of clarity of the CE

  cognitive psychologists suggest that the CE is unsatisfactory and doesn't really explain anything. the CE should be more clearly defined than just being simple 'attention'. some psychologists believe it may consist of separate components. this means that the WMM hasn't been fully explained.
• strength of the WMM: support from brain scanning studies

  braver et al.'s participants did tasks involving the CE while they were having a brain scan. activity seen in an area known as the prefrontal cortex. activity in this area increased as the task became harder. this makes sense in terms of the WMM: as demands on the CE increase, it has to work harder to fulfil its function. so this study provides evidence that the CE may have a physical reality in the brain.
• strength: word length effect supports phonological loop

  baddeley et al. found people have more difficulty remembering a list of long words (e.g. 'association') than short words. this is the word length effect. this is because there is limited space for rehearsal in the articulatory process (probably about two seconds). word length effect disappears if a person is given a repetitive task tying up the articulatory process, demonstrating the process at work.