The working memory model Flashcards
Who proposed the working memory model and when?
Baddeley and Hitch 1974
What is the WMM?
An explanation of how one aspect of short-term memory is organised and how it functions. It is concerned with ‘mental space’ that is active when we are temporarily storing and manipulating information e.g. playing chess.
What did Baddeley and Hitch propose?
- STM was not just one store, but a number of different stores
- If you do two things at the same time (dual task performance) and they are both visual tasks, you perform them less well than if you do them separately.
- If you do two things at the same time and one is visual whereas the other involves sound, then there is no interference. You do them as well simultaneously as you would do them separately.
- This suggests that there is one store for visual processing and one store for processing sounds.
- This formed the basis of the Working Memory Model (WMM) which is an explanation of how short-term memory is organised and how it functions.
What is the central executive?
The central executive has a ‘supervisory’ role and is essentially an attentional process that monitors incoming data, makes decisions and allocates slave systems to tasks.
Data arrives from our senses or long-term memory.
The central executive has a very limited storage capacity; in other words it can’t attend to too many things at once and has no capacity for storing data.
What is the phonological loop?
One of the slave systems is the phonological loop (PL), which also has a very limited capacity.
It deals with auditory information (i.e. 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, like an inner ear
The articulatory process which is used for words that are heard or seen. These words are silently repeated (looped), like an inner voice. This is a form of maintenance rehearsal. The capacity of this ‘loop’ is believed to be two seconds’ worth of what you can say
Baddeley et al. (1975) demonstrated that people find it more difficult to remember a list of long words (such as ‘association’) rather than short words, he called this the word length effect. This is because there is finite space for rehearsal in the articulatory process (probably about two seconds’ worth).
What is the visuo-spatial sketchpad?
The second slave system is the visuo-spatial sketchpad (VSS).
The VSS is a temporary store for visual and/or spatial information when required.
The VSS also has a limited capacity, which according to Baddeley is about three or four objects.
Logie (1995) subdivided the VSS into:
The visual cache which stores information about visual items, e.g. form and colour
The inner scribe which records the arrangement of objects in the visual field
What is the episodic buffer?
The third slave system is the episodic buffer. This was added by Baddeley in 2000.
It is a temporary store for information, integrating the visual, spatial and verbal information processed by other stores.
The episodic buffer maintains a sense of time sequencing (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.
The episodic buffer links working memory to LTM and wider cognitive processes such as perception.
Evaluation - dual task
A strength of the WMM is that Baddeley and Hitch (1976) supported the existence of the model with a dual performance task. All participants’ first task involved the central executive, but those who completed a second task that involved the phonological loop and the central executive completed the first task slower compared to those whose second task only involved the phonological loop. This demonstrates that there are different STM systems as it is easier to do two tasks at the same time if they use different slave systems than if they use the same slave system
Evaluation - clinical evidence
One strength is support from Shallice and Warrington’s case study of patient KF. After his brain injury, KF had poor STM ability for auditory information but could process visual information normally. For instance, his immediate recall of letters and digits was better when he read them than when they were read to him. KF’s phonological loop was damaged but his visuo-spatial sketchpad was intact. This finding strongly support the existence of separate visual and acoustic memory stores.
Evaluation - central executive
A limitation of the WMM is that the central executive component of the model is unclear. It is not clear how the central executive allocates resources to the slave systems and some psychologists believe the central executive may consist of separate subcomponents. The central executive needs to be more clearly specified than being simply ‘attention’, even recognised by Baddeley. This means that the CE is an unsatisfactory component, lowering the validity of the overall model.
