Multi-Store Memory Model: Atkinson and Shiffrin

The multi-store model of memory (MSM), proposed by Atkinson and Shiffrin, describes memory as comprising three distinct stores: sensory memory, short-term memory (STM), and long-term memory (LTM).

Information moves through these stores sequentially in a linear process, via attention, rehearsal, and retrieval.

Sensory Memory

Sensory memory (or sensory register) is like a very quick snapshot that your brain takes of everything happening around you.

It captures sights, sounds, smells, tastes, and touches – but only for an instant, typically lasting less than a second.

For example, glance at a car, then immediately close your eyes. You’ll still briefly see the image of that car in your mind for about half a second before it fades away.

Sensory memory helps you experience your environment smoothly and continuously, even though it holds each sensation only momentarily.

Key Features

• Duration: between 0.25 seconds and 2 seconds.
• Capacity: All sensory experience (v. larger capacity).
• Encoding: Sense specific (e.g. different stores for each sense).

How It Works

Think about how you briefly see the trail of a sparkler in the dark. Or notice how someone’s words seem to echo in your ears just after they’ve spoken.

These fleeting impressions happen in your sensory memory.

Because it’s so brief, most of this information disappears unless you pay attention to it, at which point it moves into your short-term memory.

The sensory stores are constantly receiving information but most of this receives no attention and remains in the sensory register for a very brief period.

Atkinson and Shiffrin (1968) explained that sensory memory stores information exactly how it’s received from your senses.

For example, images you see are stored visually (called iconic memory), and sounds you hear are stored as sounds (called echoic memory).

The sensory memory store has a large capacity but a very brief duration. It can encode information from any of the senses, and most of the information is lost through decay.

Attention is the first step in remembering something. If a person’s attention is focused on one of the sensory stores, the data is transferred to STM.

Sperling (1960) – Evidence for Sensory Memory

• Aim: To test how much information sensory memory really holds, since a whole-report test might underestimate it if items decay before they can all be reported.

• Method: Participants saw a grid of 12 letters for about 50 milliseconds. In the whole-report condition they tried to recall all 12 letters. In the partial-report condition, a tone played immediately after the display told them which single row to report.

• Results: Whole report produced only about 4-5 letters (roughly 35%). Partial report produced about 75-100% of the cued row, whichever row was cued, implying almost all 12 letters were briefly available.

• Conclusion: Sensory memory holds a large amount of information very briefly. The whole-report limit reflects rapid decay during reporting, not a small capacity, exactly as the sensory register the multi-store model proposes.

Short Term Memory

Short-term memory is like your brain’s temporary notepad, holding information for a brief period – usually about 15 to 30 seconds.

It’s what you use when remembering someone’s name you’ve just heard, a phone number you’re about to dial, or directions someone gives you.

Think of it as your mental workspace, where information stays briefly unless you actively repeat it or give it meaning.

However, short-term memory has limited space, typically holding around 5 to 9 items at once. If you don’t actively keep thinking about or rehearsing this information, it fades quickly.

• Duration: Information is held in short-term memory for a brief period, typically around 15 to 30 seconds, if it is not actively rehearsed.
• Capacity: 7 +/- 2 items
• Encoding: mainly auditory or phonemic coding (meaning it’s coded based on sound).

Maintenance rehearsal

Maintenance rehearsal is the process of verbally or mentally repeating information, which allows the duration of short-term memory to be extended beyond 30 seconds.

For example, repeating a phone number until you dial it is maintenance rehearsal. However, this method usually doesn’t involve giving meaning to the information or linking it to other memories.

This type of rehearsal usually involves repeating information without thinking about its meaning or connecting it to other information.

Continual rehearsal “regenerates” or “renews” the information in the memory trace, making it a stronger memory.

Information in short-term memory is lost because new information pushes it out (displacement) or it naturally fades over time (decay).

Long Term Memory

Long-term memory is like your brain’s personal library, storing everything you’ve learned and experienced throughout your life.

It holds memories from days, months, or even years ago. Think of the name of your childhood friend, how to ride a bike, or details from your favorite movie.

Unlike short-term memory, long-term memory has almost unlimited space and can store information indefinitely. However, for memories to last, they usually need to be meaningful or frequently used.

Think of long-term memory as a filing system: the better organized the files (or memories), the easier it is to retrieve them later.

• Duration: Unlimited (information in the LTM can potentially last a whole lifetime).
• Capacity: Unlimited
• Encoding: Mainly Semantic (based on what it means), but can be visual and auditory.

Elaborative rehearsal

If the information is given meaning (elaborative rehearsal) it is transferred from STM to LTM.

Elaborative rehearsal involves linking new information in a meaningful way with information already stored in long-term memory.

Instead of just repeating something over and over, you connect new information to something you already know or create associations that make it personally relevant.

Simply put, elaborative rehearsal is all about giving new information meaning and context, which makes it stick better in your memory.

For example, say you’re trying to remember someone’s name. You might connect it to someone else you know with the same name, imagine a vivid picture involving their name, or think about what their name means.

Elaborative rehearsal is more effective than maintenance rehearsal for remembering new information as it helps to ensure that information is encoded well. It is a deeper level of information-processing.

These meaningful connections help strengthen memories, making them easier to recall later and helping transfer information into your long-term memory.

Key Studies

These experiments test the key aspects (duration, encoding, capacity) that define the multi-store model, providing evidence for its distinct memory stores.

1. Murdock (1962) and Glanzer and Cunitz (1966) – The Serial-Position Effect

• Aim: Murdock (1962) first tested whether a word’s position in a list affects recall. Glanzer and Cunitz (1966) then asked whether primacy and recency come from separate memory stores.

• Method: Participants heard word lists and immediately recalled them, showing primacy and recency effects. In some conditions, participants first counted backwards for 30 seconds, which prevents rehearsal.

• Results: Both primacy and recency effects appeared on immediate recall. After the 30-second delay, the recency effect disappeared, but the primacy effect remained.

• Conclusion: Recency reflects a temporary short-term store emptied by the delay, while primacy reflects words already transferred to a durable long-term store. This supports two separate memory systems.

2. Peterson and Peterson (1959) – Duration of Short-Term Memory

• Aim: To measure how long short-term memory holds information without rehearsal.

• Method: Participants briefly saw trigrams (three letters, e.g. “BRT”), then counted backward by threes to prevent rehearsal. Recall was tested after delays of 3 to 18 seconds.

• Results: After just 18 seconds, recall accuracy dropped dramatically to about 10%.

• Conclusion: Short-term memory has a limited duration of roughly 18–30 seconds without rehearsal, supporting the multi-store model’s idea of STM as temporary storage.

3. Baddeley (1966a, 1966b) – Encoding in Short-Term and Long-Term Memory

• Aim: To investigate how information is encoded in short-term and long-term memory.

• Method: Participants learned word lists that were acoustically similar (e.g., caught, short, taut, nought), semantically similar (e.g., huge, great, big, wide), or dissimilar controls. They recalled the list order either immediately (testing STM) or after a delay filled with an interference task (testing LTM).

• Results: On the immediate (STM) test, acoustically similar words were recalled markedly worse, while semantically similar words showed only a small deficit (about 64% vs 71% correct). On the delayed (LTM) test the pattern reversed: semantically similar words were now recalled worst.

• Conclusion: This supports MSM by showing short-term memory is primarily acoustic, whereas long-term memory encodes mainly based on meaning.

4. Miller (1956) – Capacity of Short-Term Memory

• Aim: To explore how many items short-term memory can hold.

• Method: Reviewed various studies where participants remembered lists of letters, numbers, or words.

• Results: Most participants could accurately remember about 7 items, give or take 2 (known as Miller’s magic number, 7±2).

• Conclusion: Demonstrates short-term memory has limited storage capacity, reinforcing the MSM’s claim that STM can hold only a small amount of information at once.

5. Jacobs (1887) – Digit Span Test

• Aim: To test the capacity of short-term memory for numbers and letters.

• Method: Participants repeated sequences of digits or letters in the correct order; sequences increased in length until mistakes occurred.

• Results: Participants recalled on average 9 digits and about 7 letters.

• Conclusion: Demonstrates the limited capacity of short-term memory, supporting MSM’s idea of STM’s restricted storage.

6. Bahrick et al. (1975) – Duration of Long-Term Memory

• Aim: To investigate how long memories last in real-life settings.

• Method: Participants (aged 17 to 74) identified former classmates from yearbook photos and recalled their names years after leaving school.

• Results: Recognition remained strong (around 90%) even after 15 years, and substantial (70–80%) even after nearly 50 years.

• Conclusion: Indicates long-term memory has a very large capacity and can retain information over decades, supporting MSM’s distinction of LTM as long-lasting.

7. Conrad (1964) – Acoustic Encoding in STM

• Aim: To examine how short-term memory encodes information.

• Method: Participants saw lists of letters briefly and recalled them immediately. Letters sounded either similar (e.g., B, C, D) or different (e.g., F, H, Q).

• Results: Recall mistakes often involved mixing up letters that sounded alike, rather than those that looked alike.

• Conclusion: Short-term memory primarily encodes information acoustically (by sound), reinforcing MSM’s explanation of STM encoding.

8. HM (Henry Molaison) – Amnesia and Memory Dissociation

• Aim: To find out whether short-term and long-term memory are separate stores, using the case of a patient whose hippocampus was surgically damaged.

• Method: Surgeons removed most of HM’s hippocampus and amygdala in 1953 to relieve severe epilepsy. Researchers then studied his memory for decades, using immediate memory-span tasks and new-skill tests such as mirror-drawing.

• Results: HM’s short-term memory stayed normal, but he could never form new long-term memories. He never learned his parents had died, yet could still learn new motor skills like mirror-drawing without remembering practicing them.

• Conclusion: Intact short-term memory alongside an inability to form new long-term memories is exactly the dissociation the multi-store model predicts, showing STM and LTM are separate stores.

Critical Evaluation

Strengths

1. Clear Structure and Influential

One strength is that MSM provides a clear, easy-to-understand structure of memory.

This clear structure allows researchers to build upon and test its validity.

Its influence has led to extensive research on memory, increasing our understanding of the processes involved.

2. Evidence from Research

Numerous studies support MSM by demonstrating clear distinctions between Short-Term Memory (STM) and Long-Term Memory (LTM). For instance:

• Glanzer & Cunitz demonstrated the primacy and recency effects, showing differences in how STM and LTM function.

• Case study of HM: his intact short-term memory alongside an inability to form new long-term memories (see Key Study 8) is exactly the dissociation the multi-store model predicts.

Weaknesses

1. Oversimplification of Short-Term Memory

The MSM views STM and LTM as singular, uniform stores, but research indicates that memory is more complex and involves multiple components.

Working memory (Baddeley & Hitch, 1974) showed that short term memory is more than just one simple unitary store and comprises different components.

• Central Executive: Directs attention and allocates resources.

• Phonological Loop: Manages verbal and auditory information.

• Visuospatial Sketchpad: Handles visual and spatial data.

Baddeley and Hitch (1974) argue that the picture of short-term memory (STM) provided by the Multi-Store Model is far too simple.

Fig 2 . The Working Memory Model Components (Baddeley and Hitch, 1974)

The model proposes that every component of working memory has a limited capacity, and also that the components are relatively independent of each other.

Long-term memory is unlikely to be a single store either. It seems improbable that knowing how to play a computer game, the rules of subtraction, and what you did yesterday are all stored in the same way.

Indeed different types of long-term memory have been identified, namely episodic (memories of events), procedural (knowledge of how to do things) and semantic (general knowledge).

2. Neglects Different Types of LTM

MSM treats LTM as a single, uniform store, but research indicates multiple distinct long-term memory systems:

• Episodic memory: Personal experiences and events (e.g., your birthday party).

• Procedural memory: Skills and actions (e.g., riding a bike).

• Semantic memory: General knowledge and facts (e.g., capital cities).

3. Overemphasis on Rehearsal

Rehearsal is considered a too simple explanation to account for the transfer of information from STM to LTM.

For instance, the multi-store model ignores factors such as motivation, mood and strategy (e.g. mnemonics) which underpin learning.

Also, rehearsal is not essential to transfer information into LTM.

For example, we can recall skills we never rehearsed, such as swimming. Yet we often forget material we did rehearse, such as revision notes.

Rehearsal therefore plays a smaller role in transferring information from STM to LTM than Atkinson and Shiffrin (1968) claimed.

4 . Structure-Focused, Ignoring Detailed Processes

MSM emphasizes memory structures but overlooks detailed cognitive processes involved in memory encoding and retrieval.

The model primarily highlights attention and maintenance rehearsal, but fails to adequately explain the cognitive depth required for long-term retention:

Later models take a different approach. The levels of processing model (Craik & Lockhart, 1972) argues that the depth and meaningfulness of processing, not rehearsal itself, is what determines memory retention.

Elaborative rehearsal means analyzing information more deeply: associating it with existing knowledge, creating vivid imagery, or generating meaningful associations. This produces more durable, more easily retrievable memories than simple repetition.

Contemporary Research

Since the 1970s, many researchers have moved away from picturing short-term memory as a separate box. Instead, they treat it as the temporarily activated portion of long-term memory, held in the current focus of attention (Cowan, 2017).

Even so, a causal test still finds short-term and long-term memory can be separately targeted.

• Aim: Grover et al. (2022) tested whether working memory and long-term memory depend on separate brain systems that can each be independently boosted, using brain stimulation rather than case studies.

• Method: Adults aged 65-88 received four days of brain stimulation during a memory task. One protocol targeted the parietal cortex; another targeted the prefrontal cortex. Both memory types were tested across the four days and again one month later.

• Results: Parietal stimulation improved working memory, while prefrontal stimulation improved long-term memory. Both improvements were still present a month later.

• Conclusion: Working memory and long-term memory rely on distinct, separately targetable brain systems – a modern echo of the multi-store model’s original STM-LTM split.

References

Atkinson, R. C., & Shiffrin, R. M. (1968). Chapter: Human memory: A proposed system and its control processes. In Spence, K. W., & Spence, J. T. The psychology of learning and motivation (Volume 2). New York: Academic Press. pp. 89–195.

Baddeley, A. D. (1966a). The influence of acoustic and semantic similarity on long-term memory for word sequences. Quarterly Journal of Experimental Psychology, 18(4), 302–309. https://doi.org/10.1080/14640746608400047

Baddeley, A. D. (1966b). Short-term memory for word sequences as a function of acoustic, semantic and formal similarity. Quarterly Journal of Experimental Psychology, 18(4), 362–365.

Baddeley, A .D., & Hitch, G. (1974). Working memory. In G.H. Bower (Ed.), The psychology of learning and motivation: Advances in research and theory (Vol. 8, pp. 47–89). New York: Academic Press.

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Craik, F. I. M., & Lockhart, R. S. (1972). Levels of processing: A framework for memory research. Journal of Verbal Learning and Verbal Behavior, 11, 671-684.

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Grover, S., Wen, W., Viswanathan, V., Gill, C. T., & Reinhart, R. M. G. (2022). Long-lasting, dissociable improvements in working memory and long-term memory in older adults with repetitive neuromodulation. Nature Neuroscience, 25(9), 1237–1246. https://doi.org/10.1038/s41593-022-01132-3

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