Atkinson and Shiffrins Multistore Model » Forgetting in the Multistore Model

What you'll learn this session

Study time: 30 minutes

Understand how forgetting occurs in each store of the multistore model
Learn about decay and displacement as key forgetting mechanisms
Explore interference theory and how memories compete
Examine real-world examples of forgetting in action
Analyse research studies on memory loss and forgetting

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Introduction to Forgetting in the Multistore Model

Ever wondered why you can't remember what you had for lunch three days ago, but you can still recall your first day at school? The multistore model doesn't just explain how we remember - it also shows us exactly how and why we forget. Understanding forgetting is just as important as understanding memory itself, because it helps explain why some information sticks around whilst other information disappears forever.

In Atkinson and Shiffrin's multistore model, forgetting happens differently in each of the three memory stores. It's not just one simple process - there are actually several different ways our brains 'lose' information and each store has its own particular weaknesses.

Key Definitions:

Forgetting: The inability to retrieve information that was previously stored in memory.
Decay: The gradual fading of memory traces over time when they're not used.
Displacement: When new information pushes out old information due to limited storage capacity.
Interference: When one memory disrupts the recall of another memory.

🛠 Why Study Forgetting?

Understanding forgetting helps us improve study techniques, develop better memory strategies and even understand memory disorders. It's not just about what goes wrong - it's about how we can make things go right!

Forgetting in Sensory Memory

Sensory memory is where forgetting happens fastest and most dramatically. This store can only hold information for a fraction of a second before it's gone forever. The main cause of forgetting here is simple: decay.

Decay in Sensory Memory

Imagine you're walking down a busy street. Your eyes take in thousands of details every second - car colours, people's faces, shop signs, movements. But within half a second, most of this information has completely disappeared from your sensory memory. This isn't because you're not paying attention - it's because sensory memory has a built-in 'expiry date' that's incredibly short.

👁 Iconic Memory

Visual information lasts about 0.5 seconds before it decays completely. This is why you can't remember every single thing you saw when you walked into a room.

👂 Echoic Memory

Sound information lasts slightly longer - about 2-4 seconds. This is why you can sometimes 'replay' what someone just said even if you weren't really listening.

⚡ Rapid Decay

Without attention, sensory memories fade so quickly that we're not even aware they existed. It's like writing in disappearing ink!

Research Spotlight: Sperling's Partial Report Study

George Sperling showed participants a grid of letters for just 50 milliseconds. When asked to recall the whole grid immediately, people could only remember about 4 letters. But when given a tone to indicate which row to recall, they could remember most letters from that row - proving the information was there but decaying rapidly. This showed that sensory memory holds much more than we realise, but it disappears almost instantly.

Forgetting in Short-Term Memory

Short-term memory faces a double threat when it comes to forgetting. Not only does information decay over time, but the limited capacity means that new information can push out old information through displacement.

The Two Enemies of Short-Term Memory

Short-term memory is like a small waiting room with only 7 chairs (plus or minus 2). People can only stay in the waiting room for about 18-30 seconds before they have to leave. But if the waiting room fills up with new people, the older occupants get pushed out even sooner.

⌛ Decay in Short-Term Memory

Without rehearsal (repeating information to yourself), memories in short-term memory fade away in less than 30 seconds. This is why you might forget a phone number someone just told you if you don't keep repeating it to yourself.

🔥 Displacement in Short-Term Memory

Because short-term memory can only hold about 7 items, new information literally pushes out old information. If you're trying to remember a shopping list and someone gives you directions, the directions might displace some of the shopping items from your memory.

💡 Real-World Example

You're introduced to five new people at a party. By the time you meet the sixth person, you've probably forgotten the name of the first person you met - that's displacement in action!

Case Study: Peterson and Peterson's Trigram Study

Lloyd and Margaret Peterson gave participants three-letter combinations (like 'XQF') to remember. To prevent rehearsal, participants had to count backwards in threes from a random number. After just 3 seconds, people could recall about 80% of the trigrams. But after 18 seconds, recall dropped to less than 10%. This proved that without rehearsal, information in short-term memory decays rapidly.

Forgetting in Long-Term Memory

Long-term memory is where things get really interesting. Unlike the other stores, long-term memory has unlimited capacity and can store information for a lifetime. So why do we still forget things from long-term memory? The answer lies in interference and retrieval failure.

Interference Theory

In long-term memory, forgetting isn't usually about information disappearing - it's about information getting mixed up or blocked by other memories. Think of it like trying to find a specific book in a massive library where someone keeps moving the books around.

← Proactive Interference

Old memories interfere with new ones. Like when you keep writing last year's date on your homework in January!

→ Retroactive Interference

New memories interfere with old ones. Learning Spanish might make it harder to remember the French you learned last year.

🔍 Retrieval Failure

The memory is still there, but you can't find the right 'key' to unlock it. Like having a word 'on the tip of your tongue'.

📝 Cue-Dependent Forgetting

Sometimes we forget because we don't have the right cues to help us remember. The information is still in long-term memory, but we can't access it without the right triggers. This is why hearing an old song can suddenly bring back a flood of memories - the song acts as a retrieval cue.

Research Focus: Baddeley and Hitch's Rugby Study

Researchers studied rugby players' memories of games they'd played. They found that players who had played more games in between were more likely to forget earlier games, even if the same amount of time had passed. This supported interference theory - it wasn't time that caused forgetting, but the interference from similar memories (other rugby games).

Comparing Forgetting Across the Stores

Each memory store has its own 'forgetting personality'. Understanding these differences helps explain why we remember some things and forget others.

The Forgetting Timeline

Forgetting happens at dramatically different speeds across the three stores. It's like comparing a melting ice cube (sensory memory) to a slowly fading photograph (long-term memory).

⚡ Speed Champions

Sensory Memory: Forgets in milliseconds
Short-Term Memory: Forgets in seconds
Long-Term Memory: Can remember for decades

📈 Practical Implications

Understanding how forgetting works in each store has real practical benefits:

For studying: Use rehearsal to move information from short-term to long-term memory
For exams: Create strong retrieval cues to help access long-term memories
For daily life: Write down important information to bypass short-term memory limitations

Memory Tip: The Testing Effect

One of the best ways to prevent forgetting is to test yourself regularly. When you try to recall information, you strengthen the memory pathways and create multiple retrieval routes. This is why practice tests are so effective - they're not just checking what you know, they're actually helping you remember it better!

Evaluation and Criticisms

Whilst the multistore model's explanation of forgetting is useful, it's not perfect. Modern research has revealed some limitations in how the model explains forgetting, particularly in long-term memory.

Strengths and Weaknesses

The model does a great job of explaining forgetting in sensory and short-term memory, but it's less successful with long-term memory. Real forgetting is often more complex than the model suggests.

✓ What the Model Gets Right

Clearly explains rapid forgetting in sensory memory
Accurately describes capacity limitations in short-term memory
Provides a simple framework for understanding different types of forgetting

❌ What the Model Misses

Doesn't account for the complexity of long-term memory (procedural vs semantic vs episodic)
Oversimplifies the relationship between the stores
Doesn't explain why some memories resist forgetting better than others

Despite its limitations, the multistore model remains a valuable starting point for understanding forgetting. It provides a clear framework that helps us understand why we forget different types of information in different ways and it has practical applications for improving memory and learning.

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