Baddeley's model of working memory
This model is later expanded upon by Baddeley and other co-workers to add a fourth component, and has become the dominant view in the field of working memory.
Baddeley and Hitch's argument for the distinction of two domain-specific slave systems in the older model was derived from experimental findings with dual-task paradigms.
It can be thought of as a supervisory system that controls cognitive processes, making sure the short-term store is actively working, and intervenes when they go astray and prevents distractions.
Rather, there seem to be separate executive functions that can vary largely independently between individuals and can be selectively impaired or spared by brain damage.
In a 1971 study, Stephen Madigan demonstrated that a larger recency effect is seen during forward serial recall when people are presented a list auditorally as opposed to visually.
Catherine Penney expanded on this discovery to observe that modality effects can also be found in the case of free recall tasks.
[17] Robert Greene utilized this observation in 1987 to discover that this suffix effect has a larger impact on lists learned auditorally as opposed to visually.
[20] The visuo-spatial sketchpad is thought to be its own storage of working memory in that it does not interfere with the short term processes of the phonological loop.
[22] When this memory is in use, individuals are able to momentarily create and revisit a mental image that can be manipulated in complex or difficult tasks of spatial orientation.
The visual pathway that determines objects shapes, sizes, colors and other definitive characteristics is called the ventral stream.
This component is a limited capacity passive system,[27] dedicated to linking information across domains to form integrated units of visual, spatial, and verbal information with time sequencing (or episodic chronological ordering[27]), such as the memory of a story or a movie scene.
[28] "The episodic buffer appears...capable of storing bound features and making them available to conscious awareness but not itself responsible for the process of binding".
[30] This is based on the assumption that both the visuo-spatial sketchpad and phonological loop act as minor buffers, combining information within their sensory area.
The episodic buffer seems to be in both hemispheres (bilateral) with activations in both the frontal and temporal lobes, and even the left portion of the hippocampus.
Additionally, the mechanisms of the slave systems, especially the phonological loop, has inspired a wealth of research in experimental psychology, neuropsychology, and cognitive neuroscience.
However, criticisms have been raised, for instance of the phonological-loop component, because some details of the findings are not easily explained by the original Baddeley and Hitch model, including the controversy regarding the 7±2 rule.
[34][35] The episodic buffer is seen as a helpful addition to the model of working memory, but it has not been investigated extensively and its functions remain unclear.
