3. The working memory model

What is the working memory model and who invented it?

The working memory model was invented by Baddeley and Hitch in 1974, and it is an explanation of how one aspect of memory (STM) is organised and how it functions.

Outline the central executive.

The central executive 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 does not store information.

Outline the phonological loop

One of the subsystems is the phonological loop.

• it deals with acoustic information (which includes both what you hear and what you read)

• it is subdivided into:

• the phonological store, which stores the words you hear/read

• the articulary process, which allows maintenance rehearsal (repeating sounds or words in a ‘loop’ to keep them in working memory while they are needed and preserving the order in which information arrived)

• The capacity of this ‘loop’ is believed to be two seconds’ worth of what you say.

Outline the visuo-spatial sketchpad

The second subsystem is the visuo-spacial sketchpad.

• The VSS stores visual and/or spatial information when required. For example, if you are asked to work out how many doors there are in your home you visualise it.

• it also has a limited capacity which, according to baddeley (2003), is about three or four objects.

• Robert Logie subdivided the VSS into:

• The visual cache, which stores visual data

• The inner scribe, which records the arrangement of objects in the visual field

Outline the Episodic Buffer.

The third subsystem is the episodic buffer

• 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 four chunks (baddeley 2012)

• the episodic buffer links working memory to long-term memory and wider cognitive processes such as perception.

Evaluate the WMM (hint: clinical evidence- KF - damaged different stores, counterpoint - motorcycle accident other factors, neuroimaging evidence, nature of the central executive)

Clinical evidence ✅

support from Tim Shallice and Elizabeth Warrington’s case study (1970) on their patient KF

• his phonological loop was damaged but his visuo-spatial sketchpad was intact.

• this finding strongly supports the existence for visual and acoustic information.

-counterpoint: it is unclear whether KF suffered other cognitive issues from the motorcycle accident which might’ve affected his performance on memory tasks. This challenges evidence that comes from clinical studies of people with brain injuries that may have affected many different systems.

Neuroimaging evidence ✅

evidence from brain scans for the existnece of subsystems in working memory.

• Edward smith and john jonides (1997) used PET to show that tasks using the phonological loop were linked to activation in the left temporal and frontal lobes, while tasks using the visuo-spatial sketchpad were associated with the activity in the right parietal lobe. Furthermore, tasks requiring the central executive were associated with widespread acitvation in the frontal cortex.

• This study, and others like it, provide reliable and objective evidence for working memory’s subsystems.

Nature of the central executive ❌

lack of clarity over the nature of the central executive.

• Baddeley (2003) himself recognised 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 subcomponents.

• This means that the CE is an unsatisfactory component and this challenges the integrity of the WMM.