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What the spec says: The working memory model: central executive, phonological loop, visuo-spatial sketchpad and episodic buffer. Features of the model: coding and capacity.
OUTLINE AND EVALUATE THE WMM
A01
The WMM proposed by Baddeley and Hitch shows that there are different components (slave systems) that make up STM. The central executive gathers and processes all the information before it's sent to the relevant components and controls attention, overseas memory tasks and also controls the flow of information to and from LTM. It has a limited capacity and can be overloaded by too much information and too many tasks.
The phonological loop stores speech based information and has two parts; the phonological store (inner ear) which gathers acoustically coded items to be stored for a brief period, and the articulatory control process (inner voice) which allows repetition of sounds sub-vocally in the store. It has a capacity of 2 seconds of what you can say.
Another component in the visuo-spatial sketchpad (inner eye). It stores visual and spatial information as memory can manipulate information to take into account movement and perspective. Logie (1995) suggested that the VSS can be further sub-divided into a visual cache which stores information about shape and form, while the inner scribe records position in space and recognises speed. Additionally, the episodic buffer combines information from different sources into episodes before it's transferred to LTM.
A03
Support for the WMM comes from the case study of KF. KF's impairment was for verbal information although his memory for visual information was unaffected. If STM was one unit and it was damaged, then both verbal and visual would be impaired. However, just his phonological loop was damaged which shows that there are different acoustic and visual stores in STM as the model suggests.
Further evidence was found by Baddeley and Hitch that supports the existence of the VSS by using a dual task test. Pps were asked to do 2 tasks that utilised the VSS either separately or together. One task was to track light moving on a screen and the other to describe the angles of the letter F. It was found that pps could do both tasks separately without difficulty but when asked to do them together, their performance on both was impaired. Describing the angles was difficult because the two visual tasks competed for the limited resources of the VSS but not the verbal task which used the phonological loop. This supports the existence of the VSS being a separate component that processes visual input.
Braver et al used brain scans to show which areas were active when using the central executive. They found greater activity in the prefrontal cortex when pps did tasks involving the CE. Activity in this area increased as the task became harder. This goes in line with the model's suggestion of the CE being overloaded as it works harder to fulfill the demands of the task and supports the WMM because it clearly shows that different functions are handled by different areas of the brain.
On the contrary, there is still very little evidence to support the CE. Although it's understood that there needs to be a component to direct information, researchers are unsure as to how it should be tested and what it consists of. Some psychologists believe it may have separate components but this hasn't been explained by the WMM so it too isn't a complete explanation for memory.
One major criticism of the model is that it is experimentally reductionist in its approach. It may be that many different areas of the brain work together and contribute to attention and STM, as opposed to categorising them as one unit for verbal and another for visual. The isolation of variables simplifies complex brain processes into a simple model and this isn't an appropriate way to fully understand memory. Furthermore, much of the supporting evidence for the model comes from Baddeley who proposed the model so assumptions can be made as to whether investigator effects play a part as he may have wanted to prove his beliefs. This means that supporting evidence may not always be completely reliable and thus the model itself may be flawed.
Useful links:
https://www.youtube.com/watch?v=sVIpEvn6eRQ&list=PLUQ8QDGvbAwi31mF1w4S-xSYrRQSO8W7G&index=4
https://www.tutor2u.net/psychology/reference/working-memory-model
https://www.youtube.com/watch?v=IRBcKm0qJKE
https://www.youtube.com/watch?v=1xwNFb9tsxg