The Working Memory Model Flashcards
The working memory model
The working memory model (WMM, Baddeley and Hitch 1974) is an explanation of how one aspect of memory (short-term memory) is organised and how it functions. The WMM is concerned with the ‘mental space’ that is active when we are temporarily storing and manipulating information, for example when we are working on an arithmetic problem or playing chess or comprehending language etc.
The model consists of 4 main components, each of which is qualitatively different especially in terms of coding and capacity.
Central executive
The central executive (CE) has a ‘supervisory’ role. It monitors incoming data, focuses and divides our limited attention and allocates subsystems to tasks. The CE has a very limited processing capacity and doesn’t store information.
Phonological loop
One of the subsystems is the phonological loop (PL). It deals with auditory information (ie coding is acoustic) and preserves the order in which the information arrives. The PL is subdivided into:
-The phonological store, which stores the words you hear.
-The articulatory process, which allows maintenance rehearsal (repeating sounds or words in a ‘loop’ to keep them in working memory while they are needed). The capacity of this ‘loop’ is believed to be two seconds worth of what you can say.
Visuo-spatial sketchpad
The second subsystem is the visuo-spatial sketchpad (VSS). The vss stores visual and/ or spatial information when required. For example if you are asked to work out how many windows there are on your house you visualise it. It also has a limited capacity, which according to Baddeley (2003) is about three or four objects. Robert Logie (1995) subdivided the VSS into:
-The visual cache, which stores visual data
-the inner scribe, which records the arrangement of objects in the visual field.
Episodic buffer
The third subsystem is the episodic buffer (EB). This was added to the model by Baddeley in 2000. It is a temporary store for information, integrating the visual, spatial and verbal information processed by other stores and maintaining a sense of time sequencing-basically recording events (episodes) that are happening. It can be seen as the storage component of the central executive and has a limited capacity of about 4 chunks (Baddeley 2012). The episodic buffer links working memory to long-term memory and wider cognitive processes such as perception.
Strength-clinical evidence
One strength is support from Tim Shallice and Elizabeth Warringtons (1970) case study of patient KF. After his brain injury, KF had poor STM ability for auditory (sound) information but could process visual information normally. For instance his immediate recall of letters and digits was better when he read them (visual) than when they were read to him (acoustic). KFs phonological loop was damaged but his visuo-spacial sketchpad was intact.
This finding strongly supports the existence of separate visual and acoustic memory stores.
Counterpoint-However it is unclear whether KF had other cognitive impairments (apart from damage to his phonological loop) which might have affected his performance on memory tasks. For example his injury was caused by a motorcycle accident. The trauma involved may have affected his cognitive performance quite apart from any brain injury. This challenges evidence that comes from clinical studies of people with brain injuries that may have affected many different systems.
Strength- dual-task performance
Studies of dual-task performance support the separate existence of the Visuo-spatial sketchpad. When Baddeley et als (1975) participants carried out a visual and verbal task at the same time (dual task) their performance on each was similar to when they carried out the tasks separately. But when both tasks visual (or both were verbal) performance on both declined substantially. This is because both visual tasks compete for the same subsystem (VSS), whereas there is no competition when performing a verbal and visual task together. This shows there must be a separate subsystem (the VSS) that processes visual input (and one for verbal processing, the PL)
Limitation-Nature of the central executive
Lack of clarity over the nature of the central executive. Baddeley (2003) himself recognises this when he said, ‘The central executive is the most important but the least understood component of working memory’. The CE needs to be more clearly specified than just being simply ‘attention’. For example, some psychologists believe the CE may consist of separate sub components. This means that the CE is an unsatisfactory component this challenges the integrity of the WMM.
