WMM

• • Baddeley and Hitch (1974) proposed a multi-component model of memory, initially consisting of:

  • The central executive (CE).
  • The phonological loop (PL).
  • The visuo-spatial sketchpad (VSS).
  • A fourth component, called the episodic buffer (EB), was added in 2000.
• Working Memory Model (WMM)


  Attempts to rectify some of the criticisms of the multi-store model by proposing a more dynamic view of short-term memory
• Working memory


  A dynamic construct that allows for the manipulation of information within the short-term store
• Working memory is used when

  • Performing certain cognitive functions, such as mental arithmetic
  • Accessing information in long-term memory and transferring it to working memory where it is combined with new information and manipulated
• Central Executive (CE)


  An attentional system that processes all sensory information
• Central Executive (CE)


  • Filters information to determine what is attended to
  • Processes information in all sensory forms and directs this information to the appropriate component
  • Collects responses
  • Has a limited unknown capacity and can only effectively cope with one strand of information at a time
  • Decides how resources are shared and switches attention between different inputs of information when attention needs to be divided
• Baddeley (1996) - CE competition

  found that participants found it difficult to generate lists of random numbers while simultaneously switching between number and letters on a keyboard because the two tasks appeared to be competing for the same CE resources
• D'Esposito et al. (1995) used fMRI scans and identified that the pre-frontal cortex is activated when verbal and spatial tasks are performed at the same time, suggesting that the PFC is involved in CE
• Phonological Loop (PL)

  Deals with auditory information and consists of the inner ear and inner voice
• Phonological Loop (PL)

  • Deals with auditory information (information in the form of sound) and the order of information
  • The acoustic nature of the store also means that confusion can occur with similar sounding words
• Phonological Loop (PL) sub-systems

  • Phonological store (or inner ear) - stores words recently heard
  • Articulatory process (or inner voice) - keeps information in the PL through sub-vocalised repetition of information and is linked to speech production
• Trojani and Grossi (1995) - SC Case Study

  conducted a case study of an individual known as SC, who suffered brain damage affecting the functioning of the PL but not the visuo-spatial sketchpad (VSS), suggesting that the PL and VSS are separate systems
• Baddeley at al. (1975) - word length effect

  participants recalled more short words in serial order than longer words, and concluded that the capacity of the PL is set by the duration of words and not the number of words
• Visuo-Spatial Sketchpad (VSS)

  The 'inner eye' that handles non-phonological information
• Visuo-spatial sketchpad (VSS)

  • Temporarily stores visual and spatial information, including the relationship between them (such as what they are and where they are located)
  • Helps people to navigate around and interact with their physical environment
  • Information is coded and rehearsed through the use of mental pictures
• Visual cache (VC)


  Stores visual information in the form of colour
• Inner scribe (IS)


  Handles spatial relationships, rehearses and transfers information in the visual cache to the central executive
• Simultaneously tracking a moving point of light and performing a spatial task

  Difficulty because both tasks involved using the VSS
• Tracking the light and performing a verbal task simultaneously

  Little difficulty because one task was using the phonological loop and the other was using the VSS
• PET scans indicate that the left hemisphere of the brain is activated with visual tasks, and that the right hemisphere is activated with spatial information
• This suggests that the VC and IS are separate constructs
• Studies into the VSS often lack mundane realism because many of the studies use dual-task techniques that are rarely encountered in everyday life
• Episodic buffer (EB)


  Added to the working memory model to explain how information is integrated between the other sub-systems
• Episodic buffer (EB)


  • Temporarily stores information combined together from the central executive (CE), the phonological loop (PL), the visuo-spatial sketchpad (VSS) and long-term memory
  • Corrects problems caused by the limited capacity of both the PL and VSS as well as problems with CE storage of visual and acoustic information
• Prabhakaran et al.

  used fMRI scans and found greater right-frontal brain activation for combined verbal and spatial information, but greater posterior activation for non-combined information
• Shallice and Warrington (1974)- KF - support for wmm and msm


  LTM was unaffected by his injury, suggesting LTM and STM are different stores.

  vss unaffect unlike pl
• Suggest ways in which the WMM might be a better explanation of short-term memory than the MSM

  • it is not a unitary store
  • range of research support, eg dual-task studies, brain scanning studies
  • the WMM explains STM as a more active process than the MSM.
• Braver et al - neuroscience


  positive correlation between an increasing cognitive load (task difficulty) processed by the CE

  activation in the prefrontal cortex.