The Atkinson–Shiffrin Multi-Store Model of Memory (VCE SSCE Psychology): Revision Notes
The Atkinson–Shiffrin Multi-Store Model of Memory
Introduction to memory
Memory functions as an active information processing system that receives, organizes, stores, and recovers information. Unlike a photograph that captures an exact replica of a moment, memory operates more like a painting — it creates impressions of experiences influenced by various internal and external factors. This active nature of memory means it involves purposeful encoding, storage, and retrieval of sensory information rather than passive recording.
Research demonstrates that memory is prone to distortion. Memories can be influenced, changed, and even falsely created, highlighting the reconstructive nature of human memory systems rather than a simple recording mechanism.
The information processing model
Memory operates through a sequential three-stage process, similar to how a computer processes data. Each stage must occur in order for memory to function effectively.
The three essential stages are:
- Encoding - converting sensory information into a usable form
- Storage - retaining information over time
- Retrieval - accessing previously stored information
Encoding
Encoding involves converting sensory information into a usable form that the brain can process. This initial stage requires attention to the incoming information. Without attention, encoding cannot begin.
Example: Processing Sensory Information
When typing notes on a laptop, each keystroke converts information into a form that can be displayed on screen. Similarly, the brain converts sensory experiences (what you see, hear, or feel) into neural codes that can be processed and stored.
Storage
Storage refers to retaining information in memory over a period of time. Organized storage makes information easier to recover when needed. Like saving documents on a computer, information can be retained for varying lengths of time until required. The way information is organized during storage influences how easily it can be retrieved later.
Retrieval
Retrieval is the process of locating and recovering stored information from memory, bringing it back into conscious awareness. Effective retrieval relies on using appropriate cues or hints to locate the correct information within the vast network of memories.
When information is stored in an organized manner, retrieval becomes more efficient — similar to finding a well-labelled file on a computer rather than searching through disorganized folders.
The multi-store model of memory
The Atkinson-Shiffrin multi-store model proposes that memory consists of multiple levels, and for information to be stored long-term, sensory information must pass through a series of stores. This model is widely accepted due to its explanatory power in describing how memory works.
The model identifies three independent stores that function simultaneously and interact with each other:
- Sensory memory
- Short-term memory (STM)
- Long-term memory (LTM)
Each store processes information differently and varies in its role (function), capacity (amount of information held), and duration (length of time information is held).
Understanding the Three Key Characteristics
Every memory store can be described by three essential features:
- Role: The function of a memory store - what it does and how it contributes to overall memory processing
- Capacity: The amount of information that can be held within that store at any given time
- Duration: The length of time information remains within that store before it is either transferred, lost, or forgotten
Sensory memory
Every moment, we are bombarded with immense amounts of sensory information from both external and internal environments. Sensory memory serves as the first level of the multi-store model, receiving and storing large amounts of incoming sensory information for a very brief time.
Information entering sensory memory exists in its raw form — exactly as the sensory information is being received. For instance, when watching television, sensory memory simultaneously processes visual information from the screen, auditory information from the programme, tactile sensations from the couch, and other sensory inputs from all five senses.
Although we are not consciously aware of information held in sensory memory, attention determines which information gets transferred to short-term memory. Information not attended to is lost from memory permanently.
Example: Selective Attention in Sensory Memory
When watching TV and someone asks a question, you can attend to the question and respond, but the unattended TV content during that time will be lost. This demonstrates how attention acts as a filter, selecting which sensory information moves forward in the memory system.
Function of sensory memory
Sensory memory serves as the entry point for all new sensory stimuli. Its primary function is to filter out unnecessary information, preventing cognitive overload from the vast amount of sensory data constantly entering our awareness. This filtering occurs because sensory memory focuses on information that is novel, relevant, or personally important.
The brief duration of sensory memory allows information to be held long enough to determine whether it is important enough to warrant attention and transfer to short-term memory.
Sensory memory stores sensory impressions long enough for each impression to slightly overlap with the previous one. This overlap allows us to perceive the world as continuous rather than as disconnected images or sounds — creating the smooth flow of visual and auditory experiences we take for granted.
Capacity of sensory memory
Sensory memory possesses unlimited capacity. This storage capability is structured to handle the immense amounts of sensory stimuli entering at any given time without becoming overwhelmed.
Duration of sensory memory
Sensory memory holds information for 0.2-4 seconds. This extremely brief duration is nonetheless long enough for the brain to temporarily store and assess large amounts of sensory information to decide whether it should enter short-term memory.
Each sense has its own sensory register, and duration varies depending on the register. For example, processing an image takes less time than processing each word of a sentence. Therefore, auditory information (echoic register) has a longer duration than visual information (iconic register).
Iconic and echoic memory
Iconic memory processes visual information as an exact replica lasting 0.3-0.5 seconds with unlimited capacity.
Echoic memory processes auditory information as an exact replica lasting 3-4 seconds with unlimited capacity.
The longer duration of echoic memory allows for processing of complete sentences and spoken phrases, whereas iconic memory's shorter duration is sufficient for visual snapshots.
Short-term memory
After information has been attended to in sensory memory, it moves to short-term memory (STM). Short-term memory has limited capacity and holds information for a relatively short period unless the information is renewed through rehearsal.
Information transferred to short-term memory is no longer in raw form but exists as an encoding based on its sensory characteristics (visual, tactile, or acoustic). This memory store makes information conscious and actively manipulates it so we can retain information long enough to use it.
Short-term memory is sometimes called the "seat of conscious control" because all conscious mental processes — such as decision-making and perception — originate here.
Short-term memory uniquely accesses both other memory stores, receiving information from sensory memory and transferring information to and from long-term memory. This central position makes it the "hub" of the memory system.
Due to its limited duration and capacity, information can easily be lost unless renewed or manipulated.
Function of short-term memory
Short-term memory actively manipulates encoded information whilst completing everyday tasks. This occurs through receiving and integrating information from both sensory memory and long-term memory.
Example: Integration of New and Stored Information
When trying a new food at a café:
- Sensory memory receives information about colour, taste, and texture
- This information is sent to short-term memory
- Short-term memory retrieves existing information from long-term memory about similar foods previously eaten
- By comparing this information, short-term memory evaluates the new food
- Short-term memory sends new information (such as "this food is delicious") to long-term memory for storage
This demonstrates how short-term memory serves as a workspace where new sensory information combines with stored knowledge to create updated memories.
Capacity of short-term memory
Short-term memory has a smaller capacity than sensory memory or long-term memory, holding a limited amount of information. Research shows that an average adult can hold 7 ± 2 items, or 5-9 unrelated items, in short-term memory at any time.
When short-term memory reaches capacity, new items can only be added if old items are pushed out — a process called displacement.
The Problem of Displacement
If you are listening to teacher instructions and a friend asks a question, you may not remember the instructions because they have been displaced by your friend's question. This is why multitasking is difficult when manipulating information in short-term memory — each new piece of information can push out previous information.
Chunking
The capacity of short-term memory can be extended through chunking — grouping separate items together to form larger single units of information.
Example: Using Chunking to Extend Capacity
A 10-digit phone number appears overwhelming when treated as separate items:
- Unchunked: 1 4 6 8 7 0 2 6 1 3 (10 separate items - exceeds STM capacity)
- Chunked: 1468 702 613 (3 chunks - within STM capacity)
This works because three chunks of information do not exceed short-term memory capacity, whereas 10 separate items would. The information content remains the same, but the organizational strategy makes it manageable.
Duration of short-term memory
Short-term memory duration is limited to 12-30 seconds. If information is not manipulated after 30 seconds, it fades from short-term memory and is permanently lost through a process called decay.
Rehearsal
Decay can be prevented through rehearsal — the conscious manipulation of information to keep it in short-term memory longer or to transfer it to long-term memory.
Maintenance rehearsal involves repeating information vocally (out loud) or sub-vocally (in your head) to preserve it in short-term memory. Information can remain in short-term memory as long as you continue repeating it without interruption.
Elaborative rehearsal is more effective for transferring information to long-term memory. This technique involves giving meaning to new information and making associations with information already stored in long-term memory.
Effective Elaborative Rehearsal Techniques
Common methods include:
- Creating mnemonics
- Generating questions about the material
- Constructing mind maps
- Explaining concepts to others
Elaborative rehearsal processes information at a deeper level, resulting in more effective encoding and retrieval compared to simple repetition.
Long-term memory
After short-term memory processes information, it transfers to long-term memory (LTM) — the final level of the multi-store model. Long-term memory is a relatively permanent memory system that holds vast amounts of information for extended periods, possibly for life.
When information enters long-term memory, it undergoes further encoding according to meaning and becomes unconscious. This prevents cognitive overload from the vast amount of stored information.
Function of long-term memory
Information in long-term memory is organized semantically — meaning the meaning of words, phrases, pictures, events, or things is encoded rather than their sensory characteristics (sound, image, or texture). Semantic encoding organizes information according to meaning and personal relevance.
Well-organized memories enable more efficient retrieval. Like organized files on a laptop, semantic organization allows you to search for information based on meaning and relationships.
Example: Semantic Organization in Action
When searching for information about "tax" in your memory, semantic organization retrieves tax-related memories (income tax, tax returns, tax deductions) rather than unrelated information about "tacks" (the small pins).
Despite similar sounds, the meaning-based organization ensures you access relevant information quickly and accurately.
When information is needed, it is retrieved by locating it in long-term memory and sending it back to conscious awareness (short-term memory). Organized storage means neural networks can be searched in just a few seconds to find required information.
Capacity of long-term memory
Long-term memory capacity is unlimited, similar to sensory memory. This allows storage of a lifetime of memories. The exact amount of information long-term memory can store remains under investigation by researchers.
Duration of long-term memory
Long-term memory duration is relatively permanent, meaning information can last for extended periods, sometimes for life.
However, stored information can decay due to physical or psychological factors, particularly through disuse of particular memories and brain diseases such as Alzheimer's disease and other dementias. The term "relatively permanent" acknowledges that while LTM can hold information for life, it is not completely immune to loss.
Summary of the three memory stores
The multi-store model demonstrates how information flows through three distinct stores in a coordinated system:
1. Sensory memory receives all incoming sensory information, filters out unnecessary data, and holds attended information briefly (0.2-4 seconds) with unlimited capacity
2. Short-term memory actively manipulates encoded information in conscious awareness, holding 7±2 items for 12-30 seconds
3. Long-term memory stores semantically encoded information with unlimited capacity for relatively permanent durations
Information Flow Between Stores
Information moves through the system via specific processes:
- Sensory → Short-term: Through attention
- Short-term → Long-term: Through encoding (especially elaborative rehearsal)
- Long-term → Short-term: Through retrieval
Information can be lost at each stage through different mechanisms:
- Sensory memory: Loss of unattended information
- Short-term memory: Decay (fading over time) or displacement (pushing out by new information)
- Long-term memory: Gradual decay through disuse or disease
Remember!
Key Points to Remember:
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Memory is an active information processing system involving three sequential stages: encoding, storage, and retrieval
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The Atkinson-Shiffrin multi-store model identifies three independent but interacting stores: sensory memory, short-term memory, and long-term memory
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Sensory memory has unlimited capacity but very brief duration (0.2-4 seconds), serving as the entry point and filter for all sensory information
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Short-term memory has limited capacity (7±2 items) and duration (12-30 seconds), acting as the "seat of conscious control" where information is actively manipulated
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Long-term memory has unlimited capacity and relatively permanent duration, storing information semantically (by meaning) for extended periods or life
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Information flows between stores through attention (sensory to short-term), encoding via rehearsal (short-term to long-term), and retrieval (long-term to short-term)
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Elaborative rehearsal is more effective than maintenance rehearsal for transferring information to long-term memory
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Short-term memory can be extended through chunking — grouping separate items into larger meaningful units