Capacity of Working Memory
Relevant sections in Living Confidently with Specific Learning Difficulties (SpLDs)
Finding Your Voice with Dyslexia and other SpLDs
p106-113 Baddeley’s working memory model
Development of Dyslexia and other SpLDs
p105, 107 chunks and chunking
Text equivalent of video
Brief outline of working memory
Baddeley (2007) developed a model of working memory to include several features discovered by experimental research. His model was required to:
- process stored information
- use material from various sources, including long-term memory
- depend on a ‘limited capacity, attentional control system’
- be a flexible system that allows us to think about the real world.
The model has many components. The one of interest to this discussion is the episodic buffer, indicated by the arrow in the diagram.
Component: episodic buffer
The episodic buffer is one of the more recent components of the working-memory model.
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It stores information from several different systems, including long-term memory.
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It allows for integration of the information.
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It has limited capacity, or span, currently put at 4 chunks.
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It can manipulate the information and is involved in conscious awareness.
Capacity of episodic buffer
The capacity is determined by 4 chunks, where a chunk is ‘a package of information bound by strong associative links within a chunk, and relatively weak links between chunks’.
When 4 chunks of information are stored in the episodic buffer, any new information replaces one of the stored chunks. The figure uses an analogy with pigeon-holes to emphasis the replacement.
Just think of the number of times long numbers are given in groups of 4. There are usually no specific links between the numbers and they are not needed for long, so each number might be a single chunk for a short length of time.
When we start to learn to write words, each letter is a single chunk, so 4 letters fill the capacity of the episodic buffer and words of more than 4 letters are not held together in the buffer. Gradually links are formed with practice, and spelling is learnt. But for dyslexic people the links don’t form strongly and spelling difficulties remain a common problem.
The same applies to reading. Initially, single words will be the 4 chunks. But gradually, or quickly, the mind makes links and a reader understands the context they are reading. For dyslexic people, the links often don’t happen and reading is a word by word process, resulting in monotone voice when reading out loud.
Chunking to increase capacity
Chunking is the process of making links, or connections, between pieces of information so that much more information is stored in each chunk and the capacity of the episodic buffer, and hence working memory, can be expanded considerably.
There are many ways chunking can be done, which will be discussed in other videos or sections of this website.
The picture used in the video to represent this expansion is a comparison of a wren, one of the tiniest birds, with a golden eagle, one of the largest.
Learning how to link information together is well worth doing.
Connected videos
- Mental warm-up
- Thinking preferences
- Goals
- Motivation
- Scanning
References
Baddeley, Alan, 2007, Working Memory, Thought and Action, Oxford University Press (p145 4 chunks, pigeon holes, of memory)
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