Structures of Memory » Review and Practice - Memory Structures

What you'll learn this session

Study time: 30 minutes

The multi-store model of memory (Atkinson and Shiffrin)
Working memory model (Baddeley and Hitch)
Key components of each memory structure
Strengths and limitations of each model
How to apply these models to real-life scenarios
Techniques to test your understanding through practice questions

The Multi-Store Model of Memory

The multi-store model, proposed by Atkinson and Shiffrin (1968), suggests that memory consists of three separate stores: sensory memory, short-term memory (STM) and long-term memory (LTM). Information flows through these stores in a linear way.

Key Definitions:

Sensory memory: The initial storage of information from our senses that lasts for a very brief period (less than 1 second).
Short-term memory (STM): A temporary storage system with limited capacity that holds information for about 15-30 seconds.
Long-term memory (LTM): A permanent store with potentially unlimited capacity that can hold information for a lifetime.
Encoding: The process of converting information into a form that can be stored in memory.
Rehearsal: The process of mentally repeating information to keep it in STM or transfer it to LTM.

📖 Sensory Memory

Duration: Less than 1 second

Capacity: Very large

Encoding: Sensory (exact copy of stimulus)

This is where information first enters through our senses. If we pay attention to this information, it moves to STM. Otherwise, it's quickly forgotten.

💡 Short-Term Memory

Duration: 15-30 seconds without rehearsal

Capacity: 7±2 items (Miller, 1956)

Encoding: Mainly acoustic (sound-based)

Information that receives attention moves here. Through rehearsal, it can be maintained or transferred to LTM.

💻 Long-Term Memory

Duration: Potentially lifetime

Capacity: Unlimited

Encoding: Mainly semantic (meaning-based)

This is our permanent storage system. Information that has been rehearsed and processed deeply moves here for long-term storage.

🔃 Information Transfer

Information flows through the stores in a linear fashion:

Sensory Memory → Short-Term Memory → Long-Term Memory

Information moves from one store to the next through attention and rehearsal. Without these processes, information is lost through decay or displacement.

Research Evidence: The Multi-Store Model

Peterson and Peterson (1959) demonstrated the limited duration of STM. Participants were asked to remember three-letter combinations (like "KFT") and count backwards to prevent rehearsal. After just 18 seconds, most people forgot the letters, supporting the idea that STM has a limited duration without rehearsal.

Clive Wearing Case Study: A musician who suffered brain damage that severely impaired his ability to form new long-term memories while leaving his short-term memory relatively intact. This supports the idea that STM and LTM are separate systems.

The Working Memory Model

Baddeley and Hitch (1974) proposed the working memory model as an alternative to the simple short-term memory concept in the multi-store model. They suggested that short-term memory is more complex and active than previously thought.

Key Definitions:

Working memory: A system that allows us to hold and manipulate information while performing complex tasks.
Central executive: The control system that coordinates the other components and allocates attention.
Phonological loop: Stores and processes speech-based information.
Visuospatial sketchpad: Stores and processes visual and spatial information.
Episodic buffer: Added later (2000) to integrate information from different sources and link to long-term memory.

🗣 Phonological Loop

Deals with spoken and written material. Has two parts:

1. Phonological store: Holds speech-based information for 1-2 seconds

2. Articulatory process: Refreshes memory traces through silent rehearsal

Example: Remembering a phone number by repeating it to yourself

🎨 Visuospatial Sketchpad

Stores and manipulates visual and spatial information

Used for:

- Navigation

- Visual puzzles

- Remembering what things look like

Example: Visualising directions to a friend's house

🕹 Central Executive

The most important component that:

- Controls attention

- Coordinates the slave systems

- Selects and manipulates information

- Has limited capacity

Example: Multitasking while driving - watching the road while talking to a passenger

The Episodic Buffer

Baddeley added the episodic buffer to the model in 2000 to address limitations in the original model. This component:

Integrates information from different sources (visual, verbal, LTM)
Creates a unified memory experience
Acts as a link between working memory and long-term memory
Has limited capacity but provides additional storage

For example, when reading a book, the episodic buffer combines the visual information of the words with their meanings from long-term memory and creates a coherent narrative experience.

Research Evidence: The Working Memory Model

Dual-task studies: Participants can perform two tasks simultaneously if they use different components of working memory (e.g., repeating numbers while completing a visual puzzle). However, performance decreases when both tasks use the same component.

Brain imaging studies: Different areas of the brain activate when performing tasks associated with different components of working memory, supporting the idea that these are separate systems.

Comparing the Models

✅ Strengths

Multi-Store Model:

Simple and easy to understand
Supported by research (e.g., case studies like HM and Clive Wearing)
Explains basic memory processes

Working Memory Model:

More detailed explanation of short-term memory
Explains how we can do multiple tasks at once
Supported by brain imaging studies
Accounts for both visual and verbal processing

❌ Limitations

Multi-Store Model:

Too simplistic - memory is more complex
Focuses mainly on structure, not processes
Describes STM as a passive store rather than active
Doesn't explain how we can do multiple tasks at once

Working Memory Model:

The central executive is not well-defined
Doesn't fully explain the relationship with LTM
More complex and harder to test

Applying Memory Models to Real Life

Understanding memory structures can help us in many practical ways:

Education: Teachers can design lessons that engage multiple components of working memory (visual aids with verbal explanations) to enhance learning.
Revision techniques: Using both visual and verbal methods (mind maps with notes) engages different components of working memory.
Memory improvement: Understanding the importance of rehearsal for transferring information to LTM can help develop better study habits.
Understanding memory problems: Memory models help explain specific memory difficulties in conditions like dementia or after brain injury.

Quick Revision Tips Based on Memory Models

Use chunking: Group information into meaningful units to increase STM capacity (e.g., remember phone number 07911234567 as 079-1123-4567)
Engage multiple components: Use diagrams, spoken explanations and written notes to engage different parts of working memory
Elaborate rehearsal: Don't just repeat information; think about its meaning and connections to help transfer to LTM
Reduce cognitive load: The central executive has limited capacity, so study in a quiet environment to maximise attention

Review Questions

Test your understanding of memory structures with these questions:

What are the three stores in the multi-store model of memory?
What is the capacity and duration of short-term memory according to the multi-store model?
Name the four components of the working memory model.
How does the working memory model improve upon the multi-store model's concept of STM?
What evidence supports the separation of the phonological loop and visuospatial sketchpad?

Remember to review the content above to check your answers!

🧠 Test Your Knowledge!