The study of memory is a significant part of neuroscience as an insight into this topic could assist in the development of education, medicine and psychology. The researchers recognise several main types of memory, including long-term, short-term and working memory. The working memory model was developed in an effort to organise the current understanding of the concept and its components. Although there are specific conceptual differences between working memory and short-term memory, there are also many similarities, which means that the model could be useful for understanding short-term memory performance. The present paper will seek to apply the working memory model to short-term memory performance and to discuss the benefits and limitations of doing so.
The Working Memory Model
Working memory is concerned with short-term recall and the use of information. It helps people to perform tasks that involve the maintenance and manipulation of items, such as reading, counting, sequencing and computation. The working memory model was first developed by Baddeley and Hitch in 1974. The model involves four key components: the central executive, the phonological loop, the visuospatial sketchpad and the episodic buffer. Each part of the model plays a critical role in the processes that contribute to working memory.
First of all, the central executive is the most critical component of working memory. It has three main functions that contribute to working memory performance, including “the regulation of information flow within working memory, the retrieval of information from other memory systems such as long-term memory and the processing and storage of information.” Therefore, the central executive is the regulatory part of working memory that coordinates the flow of information from various sources and allows for its maintenance and application in different tasks. It was also suggested that the central executive takes part in a variety of cognitive processes, including mental arithmetic, semantic verification and recall of events from long-term memory. As the capacity of the central executive is limited, working memory performance is affected by the number of tasks and distractions.
Secondly, the phonological loop is a system that is designed to store verbal material. It consists of the phonological short-term store and subvocal rehearsal. Speech inputs are maintained in the phonological short-term store and subvocal rehearsal helps to refresh information and maintain memory items. The rehearsal process is also used to process nonspeech inputs, such as written words. According to Gathercole and Baddeley, subvocal rehearsal translates nonspeech data into phonological items, thus allowing maintaining them in the phonological short-term store. The performance of this component of working memory is also influenced by distractions, as well as word length, articulatory suppression and the phonological similarity of items. The visuospatial sketchpad has similar functions to the phonological loop but processes a different type of items. The sketchpad component stores visual and spatial items, as well as verbal items that can be encoded in visual form.
The final component of the model, the episodic buffer, was added after further research in 2000. The episodic buffer is “a system that can serve as both an auxiliary store when the primary ones are overloaded or disrupted, and also as a site in which to integrate diverse types of information such as verbal and spatial content within working memory”. It is also suggested that the episodic buffer can help people to memorise information by adding contextual meaning to it. The episodic buffer resolves the issues related to working memory that were discovered after the model was proposed, thus ensuring a comprehensive approach to the study of working memory.
Short-Term Memory Performance
Short-term memory is similar to working memory in many ways, which is why many researchers believe the two concepts to be inter-related. For instance, both working memory and short-term memory can hold a limited number of items for a short period of time. The primary difference between these two types of memory is that working memory maintains and applies information to tasks, whereas short-term memory is only used for maintenance of items. Nevertheless, due to the similarities in capacity and structure, it can be argued that working memory and short-term memory performance depend on similar factors. The working memory model can thus assist in gaining insight into the determinants of short-term memory performance.
Application of the WM Model to Short-Term Memory Performance
Based on the working memory model, there are two key variables that impact working memory performance: capacity and differentiation of information. First of all, as explained in the previous sections, the capacity of all components in the working memory model is limited. Although the function of the episodic buffer is to support other components of working memory when there is an overload, it is was not proven that it can contribute to the period of information maintenance or the volume of information that can be processed at a given time. Therefore, working memory performance depends on the volume of input, as well as the complexity and the number of tasks for which working memory is required. This means that distractions can reduce working memory performance by producing additional inputs of information.
In a similar way, distractions can impair short-term memory performance by increasing the volume of information and disturbing phonological or visuospatial systems involved in short-term memory. A study by Hughes and Marsh showed that serial short-term memory performance decreases if there is an irrelevant stimulus. Other studies showed that this is also true for visual short-term memory, as it requires focus on a small number of items for best performance. The application of the working memory model to short-term memory performance shows that that irrelevant stimuli play a critical role in the recall of both verbal and visual information due to the fact that they overload short-term memory systems.
Secondly, an essential aspect of the working memory model is that different types of items are processed by different systems. For instance, verbal information is handled by the phonological loop, whereas imagery is maintained in the visuospatial sketchpad. This means that working memory performance in phonological and visuospatial areas also depends on the volume of the respective type of information received. Research shows that this is also true for short-term memory, as the nature of the irrelevant stimuli determines its influence on short-term memory performance. Hence, short-term memory performance can be improved by reducing the volume of phonological or visual distractions, depending on the nature of items to be recalled.
Nevertheless, distractions that do not correspond to the type of information maintained in short-term memory can still impact performance. A study by Morey and Bieler showed that visual short-term memory could be impaired by auditory distractions. External stimuli also affect the interpretation and understanding of information, as evident from the study of learning patterns in children. By applying the working memory model to this problem, it is possible to suggest that this influence is explained by the role of the central executive. As this component of the model processes various types of information, it can be overloaded when the overall volume of inputs is high. If a similar system is involved in short-term memory, the effect of random distractions on performance in this area is justified.
One particular gap in the working memory model that affects its application to short-term memory performance is that the role of the episodic buffer and its functional areas remain rather unexplored. Therefore, it is unclear whether or not a similar structure is involved in short-term information maintenance and processing. Further studies on the mechanism of short-term memory and its relation to working memory would assist in clarifying the differences between the two types of memory.
All in all, the working memory model has four main components, and each of them performs specific functions. The relationships between these components help to outline the functional determinants of working memory performance, such as the limited capacity of systems and the differentiation of information processed by them. When applied to short-term memory performance, the model assists in determining the factors that undermine it and proposes an explanation for their negative influence. The similarity between the functional determinants of working memory and short-term memory performance is evident in research. However, further research in the area is needed to clarify whether or not a component similar to the episodic buffer is involved in short-term memory.
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