– 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.
DESCRIPTION Of THE WMM
CENTRAL EXECUTIVE
– 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
PHONOLOGICAL LOOP
– 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.
VISUO-SPATIAL SKETCHPAD
– 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.
EPISODIC BUFFER
– 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.
EVALUATION OF THE WORKING MEMORY MODEL
STRENGTHS
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.
LIMITATIONS
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.