Unlike some other models, the working memory model explains not only the storage, but also the processing of information. It is consistent with records of brain-damaged patients. For example the visuo-spatial sketch pad is said to be made of two parts, the visual component which stores information about colour and form, and the spatial component, which processes spatial and movement information. Patient ‘LH’ had more difficulty with visual tasks than spatial tasks, which probably means that there is a different part of the brain controlling these things. Another example is ‘KF’, whose forgetting of auditory stimuli was higher than visual stimuli. In the working memory model, verbal rehearsal is noted as one way to encode and store information, but there are other routes too such as visual stimuli and the episodic buffer. The model integrates a large number of research findings. As well as studies on brain damaged patients, there is also experimental evidence which supports the model, for example Baddeley and his colleagues’ word-length effect which supports the phonological loop, and a number of studies have found different brain regions to activate when people carry out tasks involving the different components of working memory. Finally, the working memory has a strong role in cognitive psychology and can be used to study other theorised systems and processes in the brain for example, consciousness, by seeing how they relate to working memory. A perfect example of this is how the central executive allows researchers to look into how memory relates to attention.
As well as strengths, the WMM also has its weaknesses. The components of the model may as yet be too simple, and do not explain the full range of day-to-day phenomena, for example, some things we’re pretty good at remembering, unless someone starts talking to us while were trying to remember it. The central executive is poorly understood. Since there are only modest correlations between people on different executive functions, and since some people can lose some executive functions but keep others, it’s highly unlikely that the CE is one unitary construct. Without knowing how the CE is broken down, it’s very difficult to come up with hypotheses to test the model further, and to know how these subsections relate to each other and the other parts of the model. Finally, researchers do not yet have a detailed understanding of how the episodic buffer combines information from the other parts of the model, and from long-term memory.