working memory model

• Baddeley and Hitch felt that STM was not just one store, but a number of different stores. This is due to dual task performance with differences between visual and audio tasks. They investigated this and it led to the working memory model. The first component is the central executive. It has limited capacity for storing and holding information and is for directing attention to particular tasks. Data arrives from the senses or the LTM and is directed into one of the other 3 sub-systems.
• One of these sub-systems is phonological loop. This store also has a limited capacity. This store deals with the auditory information and preserves the order. This can be further divided into the phonological store (holds the words you hear like an inner ear) and articulatory processes (words heard or seen. They are silently looped like an inner voice).
• ). The next sub-system is Visuo-spatial sketchpad which is used when you have to plan a task (like directions). Visual is what things look like, spatial is the physical relationship between things. Logie suggested this is split further into the inner scribe (arrangement of objects) and a visual cache (eg form and colour of objects).
• The last component was added by Baddeley in 2000, when he realised there was no general store. This is the episodic buffer. As the central executive had no capacity for storing information, this was needed for the info that could not be sorted into visual-spatial or phonological store. The episodic buffer sends information to the LTM and maintains a sense of time sequencing as well as integrating information from the visual and phonological loop.
• There are studies of brain damaged individuals that provide support for the WMM.

  A man named as KF was studied who’s short-term forgetting of auditory information was much greater than the visual stimuli. In addition, his auditory problems were limited to verbal material such as letters and digits, but not meaningful sounds. So, his brain damaged seems to be affecting the phonological loop.

  This provides evidence that there are different, separate components of the WMM.
• There are, however, a number of issues with using case studies from brain damaged patients to provide support.

  The process of brain injury is traumatic, that in itself could have altered behaviour so performance is then worse on certain tasks. The individuals may also then have other difficulties, such as paying attention, that can also decrease performance, rather than the brain damage itself. The last issue is that due to it being a unique case, it is unable to be generalised to the population.

  This is an issue for the WMM as most of the support gathered, is due to case studies.

   
• An issue with the WMM is criticisms of the central executive.

  Some psychologists feel that the concept of the central executive is too vague and doesn’t really explain much. It appears to be the same as ‘attention’. An individual called EVR was studied who had a tumour removed. He performed well on tasked requiring reasoning; this suggested his central executive was intact. However, on tasks requiring decision making he performed poorly suggesting that the central executive, was not wholly intact.

  This suggests that the central executive is much more complex than was originally suggested
• A strength in the WMM lies in the phonological loop and the explanation of the word-length effect.

  It seems that the phonological loop holds the amount of info you can say in 2 seconds. This makes it hard to remember a list of long words eg ‘psychology’ compared to shorter words such as ‘luck’. This word length effect disappears if the individual is given an articulatory suppression task for example repeating ‘the’ while reading the words. This means the shorter words cant be rehearsed more quickly than the longer words. This is evidence for the articulatory process, which is a key component.