Theories of forgetting in short term memory

So i said every so often i would release and talk about some things i am studying and learning about throughout my degree.

This has been one of my favorite Dissertations so far, as i struggle with short term memory. Having a basic understanding on what happens within the memory process will help you improve your memory!

Have a read - comments welcome. Please do not be thrown of by any big words, if you do not understanding anything i will explain.

Evaluate two or more theories of forgetting in short term memory

Short-term memory is a complex and varied phenomenon in the human mind, it is a part of a cognitive system that we use to filter and shift through memories, choosing what we remember and what we forget, we use this in every given moment of our awake self as we perceive and analyse consciously and subconsciously the world as it is before us. When we perceive an event or situation we input it via our sensory organs and then bypass it to our short-term memory, it is here for around 10-15 seconds before we decide what is relevant to us, if something stands out to us we are more likely to hold this memory, once we analyse and store what it is necessary and forget what isn’t, we can then hold these chosen short term memories for a few days in our short-term memory store, until it decays. For it to become substantially stored (in our long-term memory) we have to use a process called rehearsal, doing this we can store our memories for as long as we need considering there is no impairment or interference. Memories that have been successfully stored can be used advantageously throughout the course of a person’s life, either at school, work or even at home, providing these memories have bypassed the theories of forgetting. Short term memory is just a fraction of our ever-expanding mind, it is part of a system that helps us succeed efficiently in our lives, meeting basic needs, without short-term memory we would not be the species we are. Short-term memory is the second stage of the Multi Store Model proposed by Atkinson & Shiffrin, we still use this model to date to explain and understand the process of our memory stages.

Short term memory was highlighted in 1956 by a significant founder in Cognitive Psychology George Miller. He proposed his ‘Magic Number 7’ theory and later published a book about his findings, this is where we can only hold seven items give or take two in our memory store either as single units or in chunks, storing memories as chunks aka chunking allows us to expand our capacity therefore storing more information for example an area code is easily remembered after a few rehearsals as appose to separate single digits. Our short-term memory store as a filter shows us it has limited capacity, it has limited duration, and everything we perceive requires encoding. Memory encoding is the initial learning of information, it is how information retrieved from our sensory organs is changed into a form so it can be stored, it is where external events & occurrences are transformed so we can store them in our short-term memory & long-term memory. Which is why most things we have learnt or perceived does not get transferred out of our ultra-short or short-term memory to long term memory, we would have to subconsciously rehearse and encode every given moment, which upon research is not achievable, no one has remembered every single thing in every single second throughout a long period of time with interference, our minds aren’t capable of recording and storing so much data without documentation, so we have significant evidence throughout the years that our short term memory has many limitations, and that forgetting is a leading figure in our short-term memory.

Part of the multi store memory model is the theory of Displacement in short-term memory which Miller suggested was down to lack of capacity. The Displacement theory helps us to understand what can happen with information that goes through our memory process, as Miller proposed we can only store seven items give or take two. Evidently using a series of tests using words, letters and numbers to explain this theory, upon producing his experiment he asked participants to recall as many words, numbers or letters as they could, he found numbers were more easily recalled than letters this is also known as the serial digit span. With looking at our limited short-term memory storage capacity we can mentally form how our memory stores information, figuratively speaking you have seven boxes all full with stored information, to then hold more information you have to empty a box to allow this new information to be stored – this is displacement, we have to push something else out to store another. Displacement theory can also be broken down into primacy effect & recency effect, primacy effect suggests that information learnt first is remembered almost always, due to it already been rehearsed and transferred to our memory store, recency effect suggests that information learnt last is also remembered due to it still being in our rehearsal loop. Other studies of similar nature have been conducted over the years also that produces evidence to go against this displacement theory is the Jacobs study conducted in 1887, this would be where participants were again asked to recall numbers and letters under different conditions. Here is where the primacy effect and recency effect showed high rulings amongst participants. But the majority of these studies have been produced under strict circumstances, i.e. laboratories, universities so the majority of the participants where somewhat aware of what they wanted the results to be, the studies have a low ecological value as the vast majority of the people worldwide aren’t of that background and haven’t participated in the study that was conducted.

Another theory is trace decay theory this suggests our memories learnt leave traces and chemical imprints in our mind, but over time without recall our memories fade and decay. This theory is without consideration for outside influences, it suggests that all given memories fade over time, but that wouldn’t explain how the majority of us with no cognitive impairment have very strong vivid memories from being a child, another study which would falter this theory would be the Brown Peterson technique, here with interference our memory fades drastically and participants duration of memory with interference reached 18 seconds. Although the fundamental laws of this theory are correct, memories do fade over time with age and health defects, but this is not to say that all memories fade with no recall.

Forgetting in our short-term memory can also be due to a number of different personal factors such as stress, illness, lack of sleep, medication and other unavoidable life occurrences which can temporarily alter our memory system, these occurrences can cause our mind to go into some form of lock down as a protective barrier from stress or other factors – temporary loss of memory function, brain fog and other conditions can occur which is where the mind is temporarily down and not producing to its standard, this causes memory loss, forgetfulness and other temporary issues, when looking at the two theories of forgetting there is little to no consideration for outside factors that we do experience throughout our daily lives, with mental health rising and new health conditions emerging everyday within the mind, we have to take into consideration that these theories are a bit behind, and although we do still use the basis of each of these theories to date, we have to understand that solely using these theories with no other outside factors to help understand why we forget isn’t going to get us a substantial answer as to why a person forgets information, as there are so many different reasons as to why a person can forget temporarily and permanently.

The theories of forgetting that have been produced in the 1970’s along with the memory models cannot be a significant representation of how our memory & the course of forgetting occur, due to it being so vague, our memory is such a complex system, with many sub stores and many factors as to why we as humans can forget temporarily & permanently and remember so much information. So, to use both of the theories solely without the consideration of other factors would not be ethical in the understanding as to why we forget things in the course of our daily lives, and how we will continue to forget things forever more due to many different outside factors.

Dan Shaw


McLeod, S. A. (2008, December 14). Forgetting. Simply Psychology.

McLeod, S. A. (2009, December 14). Short-term memory. Simply Psychology.

Miller, G. A. (1956). The Magical number seven, plus or minus two: some limits on our capacity for processing information. Psychological Review, 63 (2), 81-97

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