The Working Memory Model

• What is the working memory model (WMM)?

  - Proposed by Baddeley and Hitch (1974).

  - It is a detailed explanation of how STM works, adding to the oversimplified explanation given in the MSM.

  - It looks at how STM is organised and how it functions.

  - The model consists of 4 main components:

  - Central executive (CE)

  - Phonological loop (PL)

  - Visuo-spatial sketchpad (VSS)

  - Episodic buffer (EB)
• Central executive (CE)


  - The CE coordinates the functions of the other three slave systems.

  - It monitors incoming data, focuses and divides our limited attention and allocates tasks to different subsystems.

  - The CE doesn't store information and has very limited processing capacity.
• Phonological loop (PL)

  - The PL processes auditory information and preserves the order that information arrives in.

  - It is subdivided into the phonological store and articulatory process.

  - The phonological store stores the words you hear.

  - The articulatory process allows maintenance rehearsal. The capacity of this loop is believed to be 2 seconds of what you can say.

  - The PL contributes to our learning of the sounds of language (phonology). It accesses LTM to store and retrieve information about language sounds. This allows us to develop our vocabulary as children and in a foreign language as adults.
• Visuo-spatial sketchpad (VSS)

  - The VSS stores visual and/or spatial information

  - According to Baddeley (2003), its capacity is 3-4 objects.

  - Logie (1995) divided the VSS into the visual cache and inner scribe.

  - The visual cache stores visual data.

  - The inner scribe records the arrangement of objects in teh visual field.

  - The VSS contributes to our understanding of visual semantics; the meanings of objects in our visual environment. It is able to access LTM to store and retrieve visuo-spatial information.
• Episodic buffer (EB)

  - The EB was added to the WMM in 2000 by Baddeley.

  - It is a temporary store of information that integrates visual, verbal and spatial information processed by other stores and maintaining a sense of time-sequencing.

  - It can be seen as the storage component of the CE and has a limited capacity of about 4 chunks - Baddeley (2012).

  - The EB links working memory to LTM and wider cognitive processes such as perception.
• Evaluating the WMM: Clinical evidence (with counterpoint)


  - A strength is that the WMM is supported by Shallice and Warrington''s (1970) case study of KF.

  - After his brain injury, KF had poor STM ability for auditory information, but could process visual information adequately.

  - Using the WMM, we can suggests that KF's PL was damaged, however his VSS was still intact.

  - This finding strongly supports the existence of separate visual and acoustic memory stores in STM.

  
  

  - Counterpoint: However, it is unclear if KF had other cognitive impairments which may have affected his performance on the memory task.

  - This challenges evidence that comes from clinical studies of people with brain injuries that may have affected different systems.
• Evaluating the WMM: Dual-task performance

  - A strength is that studies into dual-task performance confirm the separate existence of the VSS.

  - In Baddeley et al.'s (1975) study, participants carried out a visual and verbal task simultaneously. In this condition, performance on each task was similar to when they completed each task separately.

  - However, when both tasks were the same, performance declined substantially.

  - This is because both tasks compete for the same subsystem, whereas there is no competition when completing a visual and verbal task.

  - This shows that the VSS and PL must be separate.
• Evaluating the WMM: Nature of the CE

  - A limitation is that there is a lack of clarity over the purpose of the CE.

  - Baddeley (2003) said himself that the CE is the most crucial part to the WMM but the least understood.

  - The CE needs to be more clearly explained than just 'attention', for example, some psychologists believe that the CE consists of separate subsystems.

  - This suggests that the CE is a badly explained component, challenging the validity and integrity of the WMM.
• Evaluating the WMM: Validity of the model

  - Dual-tasks studies have been able to show that there must be separate components to working memory, i.e. the VSS and PL.

  - However, these tasks use artificial stimuli and lack external validity as they do not reflect everyday tasks that we carry out.