Key Studies on Models of Memory 🧠

Introduction: Why do some memories stay and others fade, students?

Have you ever walked into a room and instantly forgotten why you went there, but remembered the lyrics to a song from years ago? Memory is not a perfect video recording. In psychology, the cognitive approach explains behaviour by studying mental processes such as attention, memory, perception, and thinking. In this lesson, students, you will explore the key studies on models of memory, which are major pieces of evidence used to explain how memory works. 🎯

By the end of this lesson, you should be able to:

explain the main ideas and terminology behind key studies on models of memory
apply IB Psychology HL reasoning to these studies
connect the studies to the broader cognitive approach to understanding behaviour
summarize how the studies support memory models
use evidence from the studies in exam-style answers

The most important idea is that memory is often explained through models. A model is a simplified way of describing how a system works. In psychology, models of memory help researchers explain how information is stored, processed, and retrieved. The best-known model is the multi-store model of memory, but later studies also showed that memory is more active and more complex than a simple storage system. 📚

The Multi-Store Model: A starting point for understanding memory

One of the most influential models of memory was proposed by Atkinson and Shiffrin in $1968$. Their multi-store model describes memory as three separate stores: sensory memory, short-term memory, and long-term memory.

Sensory memory briefly holds information from the senses. If you see a flashing light or hear your name in a noisy room, sensory memory helps you notice it. Information that receives attention moves into short-term memory. Short-term memory has a small capacity and lasts only a short time unless it is rehearsed. Rehearsal is repeating information to keep it active. With enough rehearsal, information can enter long-term memory, which has a much larger capacity and longer duration.

This model was important because it gave psychologists a clear structure for studying memory. However, later research showed that memory is not always as simple as information moving in one straight line. That is where key studies became essential. 🧩

For example, the multi-store model explains why you might remember a new phone number for a few seconds but lose it quickly if you do not repeat it. It also explains why studying over time, rather than cramming once, often leads to better long-term recall.

Peterson and Peterson: How long does short-term memory last?

A classic study on memory duration was conducted by Peterson and Peterson in $1959$. Their goal was to find out how long information stays in short-term memory without rehearsal.

Participants were given nonsense trigrams such as $XQJ$ and then asked to count backward by threes from a three-digit number. This counting task stopped them from rehearsing the trigram. After different delay times, participants were asked to recall the trigram. The longer the delay, the worse the recall.

The results suggested that short-term memory lasts about $18$ seconds or less without rehearsal. This supported the multi-store model by showing that short-term memory is temporary. It also showed that forgetting can happen quickly if rehearsal is prevented.

Why is this useful in real life, students? Imagine hearing a locker combination at school while your friend distracts you. If you are not able to repeat the numbers in your head, the information may disappear before you can use it. 🔐

However, this study also has limits. The task was artificial, and remembering nonsense trigrams is not the same as remembering meaningful everyday information. Still, it remains a powerful example of how experimental research can test a theory.

Miller: How much can short-term memory hold?

Another important study is Miller’s work from $1956$, often summarized by the idea of $7 \pm 2$. Miller suggested that short-term memory can hold about $7$ items, plus or minus $2$.

He also introduced the idea of chunking, which means grouping separate pieces of information into larger, meaningful units. For example, the number $1\,9\,9\,8\,2\,0\,0\,3$ is harder to remember as eight separate digits than as two chunks: $1998$ and $2003$. Chunking increases the amount of information people can handle in short-term memory.

Miller’s ideas supported the view that short-term memory is limited, but not fixed in a simple way. The number of items you can remember depends on how the material is organized. This is important in the cognitive approach because it shows that memory is shaped by mental processing, not just by raw storage space.

In school, chunking helps with revision. A student may remember a list of historical dates better by grouping them into eras or events rather than learning each date alone. 📝

Bahrick et al.: How long can long-term memory last?

If short-term memory is short, what about long-term memory? Bahrick et al. investigated this in $1975$ by studying memory for high school classmates and yearbooks. They found that people could still recognize classmates and remember names decades later.

This study showed that long-term memory can last a very long time, especially for meaningful, personally relevant information. Recognition was generally better than free recall. In other words, people found it easier to identify names and faces when they saw them than to produce the names from memory without help.

The study supported the multi-store model by showing that long-term memory has impressive duration. It also highlighted that memory accuracy depends on the type of retrieval task. Recognition is usually easier than recall because the cue helps trigger stored information.

A real-world example is social media. You may not immediately recall the name of a former classmate, but once you see their photo, you recognize them instantly. That shows how cues can unlock long-term memory. 📸

Glanzer and Cunitz: Evidence for separate memory stores

Another strong piece of evidence for separate memory stores came from Glanzer and Cunitz in $1966$. They asked participants to remember lists of words. In some conditions, participants recalled the words right away. In others, there was a delay filled with a distracting task before recall.

The results showed a serial position effect: people remembered words from the beginning of the list better and words from the end of the list better than words in the middle. The first words are often remembered because of primacy effect, which occurs when early items receive more rehearsal and are transferred to long-term memory. The last words are often remembered because of recency effect, which happens because they are still in short-term memory.

When a delay was added, the recency effect disappeared, but the primacy effect remained. This supported the idea that short-term and long-term memory are separate systems.

This study is important because it gives clear experimental evidence for the multi-store model. It also helps explain exam revision strategies. If you read a list quickly without pause, you may remember the first and last items best, while the middle items are hardest to recall. ✅

Why these studies matter for the cognitive approach

Together, these studies show how the cognitive approach works in psychology. The cognitive approach uses scientific methods to investigate mental processes that cannot be seen directly. Researchers design controlled experiments, measure recall or recognition, and compare results to a theory.

The key studies on models of memory helped psychologists understand that memory has different parts and different processes. They supported the idea that people are active processors of information rather than passive receivers. They also showed that mental activity can be studied scientifically.

These studies are especially useful in IB Psychology HL because they can be used to discuss:

the structure and duration of memory stores
the role of rehearsal and chunking
the difference between recall and recognition
strengths and limitations of laboratory research
how evidence supports or challenges a model

At HL, you should also think critically. For example, many early studies used artificial tasks like nonsense syllables or word lists. This makes the findings easier to control, but it can reduce ecological validity, which means how well a study reflects real life. Even so, these studies are still important because they helped build a scientific understanding of cognition. 🧪

Conclusion

The key studies on models of memory helped psychologists explain how memory works in a structured and testable way. Peterson and Peterson showed that short-term memory is brief without rehearsal. Miller showed that short-term memory has a limited capacity, but chunking can expand it. Bahrick et al. demonstrated that long-term memory can last for many years. Glanzer and Cunitz provided evidence for separate stores through the serial position effect.

Together, these studies support the cognitive approach by showing that behaviour can be understood through internal mental processes. For IB Psychology HL, students, the most important skill is not just naming the studies, but explaining how each one supports a part of the memory model and what the strengths and limitations of that evidence are. 🧠✨

Study Notes

The cognitive approach studies mental processes such as memory, attention, and thinking.
The multi-store model of memory includes sensory memory, short-term memory, and long-term memory.
Peterson and Peterson found that short-term memory lasts about $18$ seconds without rehearsal.
Miller proposed the idea of $7 \pm 2$ items in short-term memory and introduced chunking.
Bahrick et al. showed that long-term memory can last for decades, especially for meaningful information.
Glanzer and Cunitz found the serial position effect, with primacy and recency effects.
Recall means retrieving information without direct cues; recognition means identifying information with cues.
These studies support the idea that memory is made of separate systems and processes.
A common limitation is low ecological validity because many tasks are artificial.
These studies are useful for explaining how evidence supports cognitive theories in IB Psychology HL.