Memory and the Brain

Sometimes I get confused about my memories. Sometimes they are dreams, sometimes they are photos, sometimes they are glimpses into the past, but they inhabit my mind almost constantly, living in the present is always tinged with lessons from a hazily remembered time. I sink into memories as into a warm bath, sometimes the reassurance calms me, sometimes it removes me from the present, as to float above reality to live in dream land. Its easier; sometimes.

A dictionary definition tells us that memories are:

the  mental  capacity  or  faculty of  retaining and  reviving  facts,events, impressions,etc.,or of recalling  or recognizing  previous  experiences.

A psychological definition brings a more analytical view, with Sternberg (an American psychologist) stating “Memory is the means by which we draw on our past experiences in order to use this information in the present’ (Sternberg, 1999).

Either way, the act of recalling, reminiscing, and bringing this information into our present daily lives allows for a jumble of short-term memories, long-term memories and present happenings to become mixed up, at least for me. The way in which we make memories, consuming life around us is the act of encoding, the way we experience life and transfer it into something our brains can store can be categorised into different ways according to experiences. This process is responsible for processing vast amounts of information, various forms in which we experience life are categorised and processed, for example, images, sounds or meanings. These are often taken from a sensory input, and need to be processed into something that the brain can easily store.

An acoustic encoding involves the sounds around you and goes hand in hand with a way of remembering something for short-term memory by repeating it over and over. This method is not usually used for longer term memory, as the emotional worth often associated with long-term encoding that is related to the amygdala in your brain is not often associated with short term memory.  For example, if someone gives you a shopping list to remember, you will often repeat it verbally over and over until you retain it in a short-term memory.

A visual method of encoding  is by simply seeing a list or image of something you need to remember, often this then goes hand in hand with acoustic coding, rehearsing the number or list to ourselves in order to remember. This seems to be the main method involved in short-term memory storage, however, in long-term memory, a semantic approach is more popular. Semantic coding is the process of attaching meaning to something, whether subconscious or conscious, the association of soemthing else will often lead back to the core memory. This is shown with studies into LTM and places; if you forget something you often retrace your steps into the place you first thought up an idea if you forget half way down the stairs!

Retrieval of memory is taking the information stored from ‘storage’ – this is where we can start to see a difference between STM and LTM.

STM relies a lot on a sequential method of storing, but also retrieving. Individuals often having to go through a whole number to remember the ‘fifth number in the sequence.

However LTM is stored by association, places and hings often triggering memories.

stages of memory

This process happens within the Hippocampus, part of the limbic system, situated in the temporal lobe. Responsible for the processing, the hippocampus also deals with the emotional responses in the brain, and also the memory of location of objects or people.

Image result for hippocampus

Memory is highly connected to emotion; humans often remembering moments of extreme happiness, sadness etc. – those that have an emotional impact. But without the hippocampus, you wouldn’t be able to create new memories, completely stuck in the pst. These immediate memories (STM) are sometimes turned into LTM within the hippocampus, then stored elsewhere.

The two main types of memory associated with the hippocampus are declarative memory; concerned with facts and figures, or things that can be stated verbally, and also spatial memory. Spatial memory is concerned with pathways or routes, such as remembering your way through a city, or to work.

The Amygdala however also works with similar functions, but is much more concerned with heights of emotion, often being called the ‘brains fear centre’ dealing with a flight or fight response according to a buildup of memories connected with the intensity of emotion.

In terms of childhood memory, the hippocampus remains developing until around 7 years old, meaning that longer term memories don’t seem to have quite enough time to develop as they physically cannot. However we do see small children able to remember a simple action such as pulling a level to make a toy train operate, and still remember this 2 weeks later. This almost selective ‘childhood amnesia’ baffles psychologists to this day, despite extensive research, as short-term memories seem to occur within infants. Later memories are often confused with memory cues and referencing from parents, unsure of whether it is a genuine memory or a prompted event.

Of course, Freud’s studies with his psychoanalytic theory approach shares possibly his most controversial descriptions, stating that perhaps these early memories are repressed due to their ‘inappropriately sexual nature’. He stated that the lack of memory in childhood that can be remembered later on in adult life is lacking, and memories from 2-3 are often non existent. This also baffles psychologists, as early childhood memories are often forgotten, even though the capacity of a childs scope for learning is very wide.

A childs developement with memory of course is also attached to processes such as speech development, as well as other approaches to learning such as play and imagination.

 

References 

McLeod, S. A. (2007). Stages of memory – encoding storage and retrieval. Retrieved from http://www.simplypsychology.org/memory.html

 

Dresden, D., Murrel, D. (2017) What is the hippocampus?, Available at: https://www.medicalnewstoday.com/articles/313295.php(Accessed: 9th April 2018).

Josselyn, S.A., Frankland, P.W. (2012) Infantile Amnesia: A Neurogenic Hypothesis, Available at: http://learnmem.cshlp.org/content/19/9/423.full#content-block(Accessed: 9th April 2018).

Mandal, A (2014) Hippocampus Functions, Available at: https://www.news-medical.net/health/Hippocampus-Functions.aspx(Accessed: 9th April 2018).

Phelps, J. (2014) Memory, Learning, and Emotion: The Hippocampus, Available at: http://psycheducation.org/brain-tours/memory-learning-and-emotion-the-hippocampus/ (Accessed: 9th April 2018).

Shinskey, J. (2016) Childhood Memories: Why are they so difficult to recall?, Available at: https://www.independent.co.uk/life-style/health-and-families/childhood-memories-research-early-development-recollection-culture-a7142361.html (Accessed: 9th April 2018).

Vitelli, R. (2014) Exploring Childhood Amnesia, Available at: https://www.psychologytoday.com/us/blog/media-spotlight/201404/exploring-childhood-amnesia (Accessed: 9th April 2018).

Wikipedia contributors (2018) Childhood Amnesia , Available at: https://en.wikipedia.org/w/index.php?title=Childhood_amnesia&oldid=820996400 (Accessed: 9th April 2018).

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