Case Study Support
A strength of the WMM is that the case of KF supports separate STM stores.
Shallice and Warrington (1970) carried out a case study of patient KF who had brain damage.
He has poor STM ability for verbal information but could process visual information normally (difficultly with sounds but could recall letters/digits).
So, his phonological loop had been damaged but other areas of memory were intact.
This suggests that there are separate visual and acoustic stores, however evidence from brain-damaged patients may be unreliable because it concerns unique cases of patients who have had traumatic experiences.
Duel Task Performance Studies
Another strength is that duel task performance studies support the visuospatial sketchpad.
Baddeley et al. (1975) found that participants had more difficultly doing two visual tasks (e.g. tracking a light and describing the letter F) than doing a visual and verbal task at the same time.
The greater difficulty is becasue both visual tasks compete for the same limited resources.
When doing a verbal and visual task simultaneously, there is no competition.
Therefore, duel task performance activity provides evidence for the existance of the visuospatial sketchpad while the MSM cannot explain this.
Word length effect
The word length effect supports the phonological loops.
Baddeley et al. (1975) found that people have more difficulty remembering a long list of words than a long list of short words.
This is known as the word length effect.
This occurs because there is limited space for rehearsal in the articulatory process (probably about 2 seconds).
Word length effect disappears if a person is given a repetitive task tying up the articulatory process which demonstates the process at work.
Lack of clarity over Central Executive
The WMM has a lack of clarity over the central executive and many cognitive psychologists suggest that the CE is unsatisfactory and doesnt really explain anything.
The CE should be more clearly specified than being simply 'attention'.
Some psychologists believe it may consist of separate components which means that the WMM hasn't been fully explained.
Support from brain scanning studies
Afurther strength of the WMM is that it has suport from brain scanning studies.
Braver et al.'s (1997) participants did tasks involving CE while they were having a brain scan.
Activity was seen in an area known as the prefrontal cortex and activity in this area increased as the task became harder.
This makes sense in terms of the WMM: as demands on the CE increase, it has to work harder to fulfil its function so this study provides evidence that the CE may have a physical reality in the brain.
Working Memory Model- a representation of the STM, It suggests that the STM is a dynamic processor of different types of information using sub-units coordinated by a central decision-making system
Central Executive- the component of WMM that co-ordinated activities of the three subsystems in memory. It also allocates processing resources to those activities.
Phonological loop- the component of WMM that processes information in terms of sound. This includes both written and spoken material. It is divided into the phonological store and the articulatory loop.
Visuo-spatial sketchpad- the component of the WMM that processes visual and spatial information in a mental space often called the 'inner eye'.
Episodic buffer- the component of the WMM that brings together material from the other subsystems into a single memory rather than separate strands. It also provides a bridge between working memory and the LTM.