Working Memory Model Flashcards
The Working Memory Model
The Working Memory Model was created by the scientists Baddeley and Hitch in 1974.
Baddeley and Hitch thought that the short term memory must be more complex than just a single store transferring information into the long-term memory. Due to the way that we use short term memory they felt that it must be an active processor, holding multiple pieces of information whilst those pieces of information are being worked on.
So the working memory model was meant to be a replacement for the Short-term Memory store. It initially had three components, but they added a fourth later.
So according to their model short term memory still has to interact with long term memory to place information in and to retrieve information out.
Central Executive:
The first part of the Working Memory Model is the Central Executive. This is the director/head of the model and receives and filters the information before passing it on to two ‘slave’ systems. The Central Executive is limited in capacity, so it can only hold one piece of information at a time. It switches attention between different inputs.
phonological loop
The first slave system is the phonological loop. The phonological loop deals with auditory information. It has a limited capacity and 2 second duration, so confusion can occur between similar sounding words. It is split into the primary acoustic store (‘inner ear’, dealing with sounds recently heard and holding those in your short-term memory) and the articulatory process (‘inner voice’, keeps information in your mind subvocal repetition).
Visuospatial sketchpad
The other slave system is the Visuospatial sketchpad. The visuospatial sketchpad is your ‘inner eye’. It has a limited capacity and 2 second duration, and stores visual and spatial information. This consists of the visual cache and Inner scribe. The visual cache is a passive store of form and colour of objects, and inner scribe is an active store allows you to visualise the relationship between objects and rehearse what you have seen.
episodic buffer
Later on Baddeley and Hitch thought that this model was somewhat limited, and the capacity of the phonological loop and visuospatial sketchpad was not enough to explain some research findings, so later on they added the episodic buffer to the Working Memory Model (in 2000). This is a general store to hold and combine information from the visuospatial sketchpad, phonological loop, and central executive, and then can pass that information into the long-term memory.
Testing the models
•Memory models have been tested through experimental lab studies via interference tasks and dual task experiments. These are usually well controlled, carefully run, and have large numbers of participants, meaning that their internal validity is usually quite high as they tend to produce strong results that are replicable.
•However, they lack ecological validity as environment is not their natural environment (laboratory environment), may lack mundane realism as tasks may not necessarily use memory in the way that it is naturally used, so thus may lack external validity.
•Another method used to test memory models is brain scanning. Scanners such as fMRI scanners show different areas of brain activation during separate short or long term memory tasks, indicating the separate systems.
Research on the Central Executive
Braver (1997) provides biological evidence of the central executive via brain scans. Braver found an area of the prefrontal cortex that became more active the more demanding a task was for the central executive.
Baddeley (1996) participants were asked to verbally generate random lists of numbers while also attempting to switch between typing numbers and letters on a keyboard. Baddeley found that compared to typing or generating a list of number on their own, participants performed considerably worse when completing both tasks at the same time. This shows that people have low aptitude for dual task performance, perhaps because the central executive is limited in capacity and can only cope with one type of information at a time.
Research on the Visuospatial sketchpad
Klauer and Zhao (2004) gave groups of participants either a visual task of remembering chinese ideographs, or a spatial task of remembering the location of dots on a screen. At the same time they also gave participants either a spatial or visual interference task (an interference task is a task that uses the same kind of processing as the main task). They found that spatial memory is more disrupted by spatial interference than visual memory is by visual interference. This shows that the visuospatial sketchpad has distinct visual and spatial components. This is because if visual and spatial memory were both processed the same way by one single component then interference would affect both in the same way.
Research on the Phonological loop
Baddeley (1975) Participants were visually shown 5 word lists with short exposure, then asked to write the words down in the same order. The first condition used monosyllabic words like “bond” and “yield”. The second condition used polysyllabic words like “opportunity”. Baddeley found a significant increase in recall in the first condition with the shorter words. This shows that the capacity of the phonological loop is not affected by the number of distinct items as much as by the time it takes to say them. The time limit for a word for the phonological loop was around 2 seconds. This is known as the word length effect. Words taking longer than this to say are much less likely to be remembered.
Research on the episodic buffer
Prabhakaran et al (2000) got participants to do tasks that involved equal amounts of spatial and verbal information whilst being fMRI scanned. In some tasks the spatial and verbal information was integrated, and in others it was not.The scans showed more activation in the prefrontal cortex when information was integrated, and more activation in the posterior brain regions when information was not integrated. This is potential biological evidence for the episodic buffer being located in the prefrontal cortex, as this region specialises in combining audio and visual information.
Evaluation of the Working Memory Model
•There is considerable brain imaging research showing that different areas of the brain are more active when performing different kinds of task. For example Braver (1997) provides biological evidence of the central executive via brain scans. Braver found an area of the prefrontal cortex that became more active the more demanding a task was for the central executive.
•A Shallice and Warrington (1974) case study reported that brain-damaged patient KF could recall visual but not verbal information immediately after its presentation, which supports the WMM’s claim that separate short-term stores manage short-term phonological and visual memories.
•The central executive has been criticised by other psychologists as a vague concept without full explanation of its function and is quite difficult to test (not fully falsifiable). Baddeley admits that the concept needs development, and included the episodic buffer as part of this development.
