How do models of memory explain the way information is encoded, stored and retrieved?
Describe and compare the Atkinson-Shiffrin multi-store model and the working memory model, including encoding, storage and retrieval
WACE Year 12 Psychology Unit 3: the Atkinson-Shiffrin multi-store model of sensory, short-term and long-term memory, the Baddeley and Hitch working memory model, and the processes of encoding, storage and retrieval.
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What this dot point is asking
SCSA expects you to describe each model, give the capacity and duration of each store, distinguish encoding, storage and retrieval, and compare the two models. The marked detail is the precise figures and the way the models differ in how they treat short-term memory.
The three memory processes
All memory depends on three processes.
- Encoding is converting incoming information into a usable form for storage (visual, acoustic or semantic).
- Storage is retaining the encoded information over time.
- Retrieval is recovering stored information when it is needed, through recall, recognition or relearning.
The Atkinson-Shiffrin multi-store model
Richard Atkinson and Richard Shiffrin proposed that memory is made of three separate stores through which information flows.
- Sensory memory is a very brief, large-capacity register that holds raw sensory input. Iconic (visual) memory lasts about 0.3 seconds and echoic (auditory) memory about 3 to 4 seconds. Information that is attended to passes into short-term memory.
- Short-term memory (STM) holds about seven items (Miller's magic number, plus or minus two) for roughly 18 to 30 seconds without rehearsal. Maintenance rehearsal keeps information in STM; elaborative rehearsal transfers it to long-term memory.
- Long-term memory (LTM) has effectively unlimited capacity and can last a lifetime. Retrieval brings information from LTM back into STM for use.
The working memory model
Alan Baddeley and Graham Hitch argued that short-term memory is not a single passive store but an active system, which they called working memory. It has several components.
- The central executive directs attention and coordinates the other components. It has limited capacity.
- The phonological loop handles verbal and auditory information (an inner voice and inner ear), letting us rehearse and store sounds and words.
- The visuospatial sketchpad handles visual and spatial information (an inner eye), letting us picture and manipulate images.
- The episodic buffer (added later) integrates information from the components and links it to long-term memory.
Because the components are separate, we can perform two tasks at once if they use different components (listening while picturing a route), but struggle if two tasks compete for the same component.
Comparing the models
The multi-store model is simple and explains the distinct stores and the effects of rehearsal, but it treats short-term memory as a single passive container. The working memory model better explains how we actively manipulate information and do two things at once, but is more complex and focuses mainly on the short-term system. The models are complementary rather than contradictory: working memory is a more detailed account of the short-term store in the multi-store model.
Why models of memory matter
Models of memory explain study techniques (chunking to beat the seven-item limit, elaborative rehearsal to build durable memories), the effects of brain damage on specific memory components, and why divided attention impairs performance. They also set up the next dot point on forgetting and the reliability of memory.