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Unlock This CourseMemory is one of the most important cognitive processes we have. Without it, we couldn't learn, recognise faces, or even remember what we had for breakfast! In 1968, two psychologists called Richard Atkinson and Richard Shiffrin created a model to explain how our memory works. They suggested that memory isn't just one big storage system, but actually three separate stores that work together.
Think of it like a factory production line - information flows from one stage to the next, getting processed along the way. This became known as the Multi-Store Model and it's still one of the most important theories in psychology today.
Key Definitions:
The Multi-Store Model suggests that information flows through three distinct memory stores, each with different characteristics and functions. Understanding these stores helps us understand how we process and remember information in our daily lives.
Let's explore each of the three memory stores in detail. Each store has its own unique characteristics, including how long information stays there, how much it can hold and how information is processed.
The sensory register is like a brief snapshot of everything around you. It holds information from your senses (sight, sound, touch, taste, smell) for a very short time - usually less than a second. Most of this information disappears quickly unless you pay attention to it.
Less than 1 second for most information. Visual information lasts about 0.5 seconds, whilst auditory information can last up to 2 seconds.
Unlimited - it can hold all the sensory information you're exposed to at any moment.
Information is stored in its original sensory form - visual images, sounds, physical sensations.
Short-term memory is like your mental workspace. It's where you hold information that you're currently thinking about or working with. For example, when someone tells you a phone number and you repeat it to yourself until you can write it down, you're using your short-term memory.
About 18-30 seconds without rehearsal. You can extend this by repeating the information to yourself.
Limited to about 7±2 items (between 5-9 pieces of information). This is called Miller's Magic Number.
Mainly acoustic (sound-based). We often repeat information to ourselves using our 'inner voice'.
Long-term memory is like a vast library that stores all your knowledge, experiences and skills. Unlike short-term memory, it can hold an enormous amount of information for very long periods - potentially your entire lifetime.
Potentially unlimited - from minutes to a lifetime. Some memories can last forever.
Unlimited - there's no known limit to how much information can be stored.
Mainly semantic (meaning-based). Information is stored based on its meaning and connections to other memories.
Bennet Murdock wanted to test whether the Multi-Store Model was correct. He designed a clever experiment to see if people really do have separate short-term and long-term memory stores. His study became one of the most famous experiments in psychology and provided strong evidence for the Multi-Store Model.
Bennet Murdock was an American psychologist who conducted his famous serial position study in 1962. He was interested in understanding how memory works and wanted to test the newly proposed Multi-Store Model. His research helped establish some of the fundamental principles of how we remember information.
Murdock's experiment was beautifully simple but incredibly revealing. Here's exactly what he did:
Participants: He used volunteer participants (the exact number varied across his studies, but typically around 20-40 people).
Method: Participants were presented with lists of words, usually between 10-40 words long. The words were presented one at a time, typically at a rate of one word per second. After hearing the complete list, participants were asked to recall as many words as possible in any order they wanted (this is called free recall).
Materials: The words were common, everyday words that participants would easily understand. Murdock made sure the words weren't related to each other, so participants couldn't use connections between words to help them remember.
When Murdock analysed the results, he found something fascinating. People didn't remember all positions in the list equally well. Instead, there was a clear pattern:
When Murdock plotted the results on a graph, he found a distinctive U-shaped curve. People remembered words at the beginning of the list very well, forgot most of the words in the middle and remembered words at the end quite well too.
This pattern became known as the serial position effect and it consists of two parts:
1. The Primacy Effect: Words at the beginning of the list were remembered well. Murdock found that the first few words had about 80% recall rate.
2. The Recency Effect: Words at the end of the list were also remembered well. The last few words had about 70% recall rate.
3. The Middle Ground: Words in the middle of the list were poorly remembered, with recall rates dropping to around 20%.
Murdock's results provided strong evidence for the Multi-Store Model. Here's how the model explains each part of the serial position curve:
The primacy effect happens because the first words in the list get special treatment. When you hear the first word, your short-term memory isn't full yet, so you can rehearse it (repeat it to yourself) multiple times. This rehearsal helps transfer the information into long-term memory.
As more words are presented, you have less time to rehearse the early words, but they've already had a head start. Think of it like this: if you're trying to remember a shopping list, you'll probably repeat the first few items several times before new items are added.
The recency effect is explained by short-term memory. The last few words you heard are still fresh in your short-term memory when you're asked to recall them. They haven't had time to fade away yet.
However, there's a catch - the recency effect disappears if there's a delay before recall, or if you have to do another task first. This supports the idea that these words are held in short-term memory, which has a limited duration.
Words in the middle of the list suffer from the worst of both worlds. They don't get enough rehearsal to transfer to long-term memory (unlike the first words) and they're not recent enough to still be in short-term memory (unlike the last words).
These middle words get displaced from short-term memory by the words that come after them and they haven't been rehearsed enough to make it into long-term memory.
The serial position effect isn't just a laboratory curiosity - it affects us in real life too! For example, in job interviews, candidates who go first or last are often remembered better than those in the middle. When studying, it's harder to remember information from the middle of your revision session. Understanding this can help you plan better study strategies!
Like all psychological theories, the Multi-Store Model and Murdock's supporting evidence have both strengths and limitations.
Since Murdock's study, our understanding of memory has evolved significantly. Researchers have discovered that long-term memory isn't just one store, but consists of different types including episodic memory (personal experiences), semantic memory (facts and knowledge) and procedural memory (skills and habits).
The Working Memory Model, proposed by Baddeley and Hitch, has also replaced the simple short-term memory store with a more complex system that actively processes information rather than just storing it.
However, Murdock's serial position study remains a cornerstone of memory research. It elegantly demonstrated that memory consists of multiple systems and provided crucial evidence for one of psychology's most important theories.
Use the serial position effect to improve your studying: Start and end revision sessions with the most important information. Take breaks to create multiple 'beginnings' and 'endings'. When learning lists, pay extra attention to middle items. Space out your learning rather than cramming everything at once.