Models of memory: WACE Year 12 Psychology Unit 3
“Models for explaining memory: the processes of encoding, storage and retrieval; features of the multi-store model (Atkinson and Shiffrin, 1968), including the duration, capacity and encoding of the sensory register, short-term memory and long-term memory (procedural and declarative, semantic and episodic); and features of the working memory model (Baddeley and Hitch, 1974; Baddeley, 2000)”
Memory works through encoding, storage and retrieval. The multi-store model (Atkinson and Shiffrin, 1968) describes a sensory register, short-term memory and long-term memory, each with its own duration, capacity and type of encoding, and splits long-term memory into procedural and declarative (semantic and episodic) memory. The working memory model (Baddeley and Hitch, 1974; Baddeley, 2000) replaces the single short-term store with an active system: a central executive, phonological loop, visuospatial sketchpad and episodic buffer.
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What this dot point is asking
The SCSA syllabus lists the three memory processes, the features of each store in the multi-store model (duration, capacity, encoding), the types of long-term memory, and the four components of the working memory model. Expect to label a diagram of either model, fill in a table of store features, apply a model to a scenario, and compare the two.
Encoding, storage and retrieval
- Encoding converts incoming information into a form that can be stored. It can be visual (images), acoustic (sounds) or semantic (meaning).
- Storage keeps encoded information over time.
- Retrieval brings stored information back into conscious awareness when it is needed, through recall, recognition or relearning (see recall, recognition and relearning).
A failure at any of the three stages produces forgetting, which is why exam questions often ask which process has broken down.
The multi-store model (Atkinson and Shiffrin, 1968)
Richard Atkinson and Richard Shiffrin proposed that information flows through three separate stores. Attention moves information from the sensory register into short-term memory, and rehearsal transfers it into long-term memory. Retrieval brings it back from long-term memory into short-term memory to be used.
| Store | Duration | Capacity | Encoding |
|---|---|---|---|
| Sensory register | Very brief: about 0.2 to 0.5 s (iconic, visual); about 3 to 4 s (echoic, auditory) | Very large | Raw sensory form (the same form as the stimulus) |
| Short-term memory | About 18 to 30 s without rehearsal | About 7 plus or minus 2 items | Mainly acoustic |
| Long-term memory | Potentially a lifetime | Effectively unlimited | Mainly semantic |
These three features are what the syllabus names for every store, so learn them as a set of nine facts. A common short answer item gives you one feature and asks you to name the store.
Types of long-term memory. The syllabus splits long-term memory into:
- Procedural memory: memory for skills and actions, such as typing or swimming. It is implicit: you retrieve it without conscious effort and often cannot put it into words.
- Declarative memory: memory that can be consciously recalled and stated. It has two forms:
- Semantic memory: general facts and knowledge, such as the meaning of a word or the capital of a country.
- Episodic memory: personal experiences tied to a particular time and place, such as your last birthday.
The working memory model (Baddeley and Hitch, 1974; Baddeley, 2000)
Alan Baddeley and Graham Hitch argued that short-term memory is not one passive store but an active workspace where information is held and manipulated. Their 1974 model had three components; Baddeley added a fourth in 2000.
- Central executive: the control system. It directs attention, decides which component handles which task and coordinates them. It has limited capacity and does not store information.
- Phonological loop: holds speech-based and other sounds for a short time, and uses inner rehearsal to keep them active (repeating a phone number under your breath).
- Visuospatial sketchpad: holds and manipulates visual and spatial information (picturing the layout of your house to count the windows).
- Episodic buffer (Baddeley, 2000): a limited-capacity store that combines information from the other components into a single episode and links working memory with long-term memory.
Because the phonological loop and the visuospatial sketchpad are separate, a verbal task and a visual task can run at the same time with little interference, but two verbal tasks compete for the phonological loop and performance drops.
Comparing the two models
| Multi-store model | Working memory model | |
|---|---|---|
| View of short-term memory | A single, passive store | An active system of several components |
| Main strength | Clear account of the separate stores and the role of attention and rehearsal | Explains how we manipulate information and do two tasks at once |
| Main limitation | Oversimplifies short-term and long-term memory as single stores; says rehearsal is the only route to long-term memory | Says little about long-term memory; the central executive is vague and hard to test |
The models are best seen as complementary: working memory is a detailed account of what happens in the short-term stage of the multi-store model.
Remembering a Wi-Fi password read aloud
A friend reads out a Wi-Fi password while you look at your laptop.
Multi-store model. The sound enters the sensory register (echoic memory, about 3 to 4 seconds). Because you attend to it, it passes into short-term memory, where it is encoded acoustically. You can hold about 7 plus or minus 2 characters, so a 12-character password is likely to be lost unless you rehearse or chunk it.
Working memory model. The central executive directs attention to the password. The phonological loop holds the characters as you repeat them under your breath, while the visuospatial sketchpad handles the position of the keys on the keyboard. Because these components are separate, you can type and rehearse at the same time. If you link the password to something meaningful, the episodic buffer helps connect it with long-term memory.
Marker's note: name the model, name the store or component, and link each to a specific part of the scenario.
- Mixing up the features
- Short-term memory is mainly acoustic and long-term memory mainly semantic. Do not swap them, and remember the sensory register holds information in its raw sensory form.
- Leaving out the episodic buffer
- The syllabus names Baddeley (2000), so the current model has four components, not three.
- Calling procedural memory declarative
- Knowing how to ride a bike is procedural; knowing that a bike has two wheels is semantic; remembering your first ride is episodic.
- Treating working memory as just another name for short-term memory
- Working memory is an active system that manipulates information, which is its main difference from the multi-store model.
Practise drawing both models from memory with labelled arrows (attention, rehearsal, retrieval for the multi-store model; the central executive linked to the two slave systems and the episodic buffer for working memory). Extended answers can include clearly labelled diagrams with explanatory notes.
Exam-style questions
Questions in the style of SCSA exam questions on this dot point, each with a worked answer. They are written by ExamExplained unless tagged "Past paper"; the year shows the paper a question is modelled on.
Original6 marksDescribe the four components of the working memory model (Baddeley and Hitch, 1974; Baddeley, 2000) and explain one way the model improves on the multi-store model's account of short-term memory.Show worked answer →
A 6 mark response needs the four components (1 mark each) plus the improvement (2 marks).
- Central executive
- Directs attention to the other components and coordinates them; it has limited capacity and does not store information itself.
- Phonological loop
- Holds and rehearses verbal and auditory information (the inner voice).
- Visuospatial sketchpad
- Holds and manipulates visual and spatial information (the inner eye).
- Episodic buffer
- Added by Baddeley in 2000; a limited-capacity store that combines information from the other components and links it with long-term memory.
- Improvement
- The multi-store model treats short-term memory as a single passive store. The working memory model treats it as an active system with separate components, which explains why two tasks can be done at once if they use different components (listening to directions while looking at a map) but not if they compete for the same one.
Original8 marksCompare the sensory register, short-term memory and long-term memory in the multi-store model (Atkinson and Shiffrin, 1968) in terms of duration, capacity and encoding, and distinguish between procedural and declarative long-term memory.Show worked answer →
An 8 mark response needs the three features for each store (6 marks) and the long-term memory distinction (2 marks).
- Sensory register
- Duration: very brief, about 0.2 to 0.5 seconds for visual (iconic) and about 3 to 4 seconds for auditory (echoic) information. Capacity: very large. Encoding: information is held in its raw sensory form.
- Short-term memory
- Duration: about 18 to 30 seconds without rehearsal. Capacity: about 7 plus or minus 2 items. Encoding: mainly acoustic.
- Long-term memory
- Duration: potentially a lifetime. Capacity: effectively unlimited. Encoding: mainly semantic (by meaning).
- Procedural versus declarative
- Procedural memory is memory for how to do things (riding a bike) and is implicit, retrieved without conscious effort. Declarative memory is memory for facts and events that can be consciously stated: semantic memory holds general knowledge (Perth is the capital of WA) and episodic memory holds personal experiences tied to a time and place (your first day of Year 12).
Practise this
Sources & how we know this
- Psychology ATAR course Year 12 syllabus (effective from 1 January 2024) — School Curriculum and Standards Authority (SCSA)
- Psychology ATAR course: syllabus and support materials — SCSA
- Past ATAR course examinations — SCSA