The Working Memory Model

– Baddeley and Hitch felt that the STM was not just one store, but a number of different stores

– This is because if you do two things at once and they are both visual tasks you don’t perform as well as if you did them separately

– But, if you do two things at once when one is visual and the other is auditory then there is no interference

– The working memory model is an explanation of how short term memory is organised and how it functions.

– The model consists of four main components, each of which is qualitatively different especially in terms of capacity and coding.



– The function of the CE is to direct attention to a particular task

– The CE is attentional process that monitors incoming data (From the slave systems), makes decisions and allocates slave systems to tasks.

– The central executive has a very limited storage capacity and can’t attend to too many things at once


– One of the slave systems

– It deals with auditory information and preserves the order in which the information arrives.

– The phonological loop is subdivided into:

– The phonological store which stores the words you hear

– The Articulatory process which allows maintenance rehearsal in a ‘loop’ to keep them in working memory while they are needed.

-The capacity of this ‘loop’ is said to be two seconds’ worth of what you can say.


– One of the slave systems

– This stores visual (What things look like) and/or spatial (Physical relationship between things) information when required.

 – The visuo-spatial sketchpad is subdivided into:

– The visual cache which stores visual data

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

– It also has a limited capacity, which according to Baddeley, is about three or four objects.


– One of the slave systems

– This was added to the model by Baddeley in 2000.

– It is a temporary store for information that brings together materials from other subsystems into a single memory rather than separate strands

– The episodic buffer links working memory to LTM and wider cognitive processes such as perception.

– It has limited capacity of about four chunks.



Research Support – KF

– KF suffered brain damage which resulted in poor STM ability for verbal information but could process visual information normally.

– This suggests that just his phonological loop had been damaged leaving other areas of memory intact.

– This supports the existence of a separate visual and acoustic store.

– However, evidence from brain-damaged patients may not be reliable because it concerns unique cases with patients who have had traumatic experiences.


Dual task performance

– In 1975 Baddeley showed that participants had more difficulty doing two visual tasks than doing both a visual and verbal task at the same time.

– This increased difficulty is because both visual tasks compete for the same slave system whereas, when doing a verbal and visual task simultaneously, there is no competition.

– This means there must be a separate slave system that processes visual input and so this study supports the separate existence of the visuospatial sketchpad.


Central executive

– Cognitive psychologists suggest that the central executive component is unsatisfactory and doesn’t really explain anything.

– All it appears to do is allocate resources and essentially be the same as ‘attention’.

– Critics also feel that the notion of a single central executive is wrong and there are probably several components.

– There was a case study on EVR, who had a cerebral tumour removed.

– He performed well on tests requiring reasoning, which suggested that his Central executive was intact.

– However, he had poor decision-making skills, which suggested that in fact his central executive was not intact.

– In summary the central executive is seen as unsatisfactory because it is probably more complex than Baddeley and hitch originally suggested.

Case Studies

– There are a number of problems with using evidence from case studies of individuals who have suffered serious brain damage.

– First of all, the process of brain injury is traumatic, which may in itself change behaviour so that a person performs worse on certain tasks.

– Second, such individuals may have other difficulties such as difficulties paying attention and therefore underperforming certain tasks.

– Finally case studies are of unique individuals and cannot be generalised to the population and therefore lack population validity.

– This is an issue for the working memory model as some of the key research that supports the working memory model comes from case studies.