Multi-store Model of Memory (Atkinson and Shiffrin, 1968)

Introduction to the Multi-store Model of Memory

Have you ever wondered how your brain decides what to remember and what to forget? In 1968, two researchers named Richard Atkinson and Richard Shiffrin proposed a famous theory called the Multi-store Model of Memory (MSM). They suggested that memory isn't just one big "blob" in our heads, but instead, it works like a series of storage boxes that information flows through. This model is a key part of Topic 2: Memory and helps us understand how we process everything from a phone number to a childhood memory.

The Three Memory Stores

The MSM describes three distinct "stores" where information is kept. Think of these as three different rooms in a house: some things stay for a split second, while others stay forever.

1. The Sensory Register

This is the very first "entry point" for information. Everything you see, hear, smell, or touch enters here first.
- Capacity: Very large (it takes in everything around you).
- Duration: Very brief (usually less than \(1\) second).
- Example: When you walk past a shop, you see hundreds of items. You "sense" them all, but they disappear almost instantly unless you pay attention to them.

2. Short-Term Memory (STM)

If you pay attention to something in the sensory register, it moves into your Short-Term Memory.
- Capacity: Limited. Most people can hold between \(5\) and \(9\) "bits" of information (often called \(7 \pm 2\)).
- Duration: Limited. Information stays here for about \(18\) to \(30\) seconds unless you keep repeating it.
- Quick Note: You will learn more about the exact duration of STM in the study by Peterson and Peterson (1959).

3. Long-Term Memory (LTM)

If you repeat information enough times, it moves into your Long-Term Memory.
- Capacity: Potentially infinite. There is no known limit to how much you can remember!
- Duration: Potentially a lifetime. You might remember your first day of school even decades later.
- Example: Your name, your birthday, and how to ride a bike are all stored in your LTM.

How Information Moves: The Processes

Atkinson and Shiffrin explained that information doesn't just sit there; it moves between stores through specific processes. Don't worry if this seems like a lot to remember—just think of it as a journey!

A. Attention: This is the "gatekeeper." If you don't pay attention to what you see or hear, it never makes it past the sensory register.

B. Rehearsal: This is when you repeat information over and over to yourself. There are two types:
- Maintenance Rehearsal: Repeating a phone number in your head to keep it in your STM.
- Prolonged Rehearsal: Repeating it enough times so that it "sticks" and moves into your LTM.

C. Retrieval: When you want to use a memory that is stored in your LTM, you have to "get it out" and bring it back into your STM. This process is called retrieval.

D. Forgetting: If information isn't rehearsed, it is lost through decay (fading away) or displacement (being pushed out by new information because the STM is full).

Summary Table: Features of STM and LTM

Short-Term Memory (STM)
- Duration: \(18-30\) seconds
- Capacity: \(7 \pm 2\) items
- Moving to next store: Requires rehearsal

Long-Term Memory (LTM)
- Duration: Up to a lifetime
- Capacity: Infinite
- Moving back to STM: Requires retrieval

Evaluating the Multi-store Model

In your exam, you need to be able to talk about the strengths (good things) and weaknesses (limitations) of this theory.

Strengths

• Scientific Evidence: There are many studies, like Peterson and Peterson (1959), that prove STM and LTM are different because they have different durations and capacities.
• Case Studies: People with amnesia (like Henry Molaison) provide evidence. Some patients can remember things from years ago (LTM is working) but cannot form new memories (STM is not passing info to LTM). This proves the stores are separate.

Weaknesses

• Too Simple: The model suggests that LTM is just one big "store." However, we now know we have different types of LTM (like remembering facts vs. remembering how to swim).
• The Role of Rehearsal: Atkinson and Shiffrin argued that we must rehearse information to remember it. However, in real life, we often remember "flashbulb" events (like a car crash or a surprise party) even though we never sat down to rehearse them!

Quick Review: Check Your Understanding

Did you know? The idea that we can hold about \(7\) items in our STM is why phone numbers (without the area code) are usually 7 digits long!

Common Mistake to Avoid: Many students think that "forgetting" only happens in the LTM. Remember, you can forget things in the Sensory Register (by not paying attention) and in the STM (by not rehearsing) too!

Key Takeaway:

The Multi-store Model (1968) sees memory as a flow of information through three stores: Sensory Register \(\rightarrow\) Short-Term Memory \(\rightarrow\) Long-Term Memory. The key processes are attention and rehearsal.