Memory is the capability of the brain to hold onto the past or currently happening events and different pieces of information, so they can be utilized in the future, at the time of need. Human memory storage is one of the greatest marvels of nature. The long and complex course of evolution provided human beings with a mind which is an astonishing example of adroitness and dexterity. Our brain is the main key that unlocked the attics of the food chain for us.
Learning and adaptation, are two crucial things that are required for survival in any environment. These two are staunchly linked with memory. The forte of memory is not only about keeping things as it is, but it is also a far complex process having various stages through which the information is passed and processed, so it can be used to facilitate the processes of adaptation and learning. This particular phenomenon can be understood by a simple example. Whenever you are walking, driving, scrolling on your phone, or just simply sitting somewhere, you are in connection with your environment. Sometimes this connection is so passive that you do not even realize it. The human brain is continuously making thoughts and these thoughts are created by some sort of sensory information.
Every single thought begins with a piece of sensory information. The information is always entering the brain, stimulating it and creating a thought which may last a few seconds or sometimes the stimulus or information is so strong that it can create some sort of pattern or it gets engraved in our mind which lasts longer, in such cases you can even recall that particular time even after years. The sensory information can be visual if perceived by eyes, auditory if enters your brain through your ears, it can be a particular scent that lingers in your brain for a long time, or it can be a certain type of touch anticipated by the sensory neuron forming baroreceptors on your skin. Your senses play the most important role in the formation of memories which directly and indirectly make us learn and adapt according to the environment.
This is interesting to know that our brain is continuously catching information, but it never gets flooded or overwhelmed by it (in normal and non-pathological circumstances). Because our brain utilizes different levels of memory storage. The things which are at lower levels of attention and priority get forgotten. The human brain keeps discarding them and only stores the things which we need.
Storeroom as an Analogy
We can understand how the human brain stores information by using a simple analogy. Our brain is like a storeroom when we consider memory storage. Like in a store you want to keep the important things on the shelf because in that way they will become easily accessible. Similarly, our brain keeps important things on the surface levels of memory storage. You pay attention to the things that you like, that is why subjects of your interest are easier for you to remember as compared to the things which you do not like.
That is why some people believe that it helps to organize your mind by yourself, by trying to remember only the things which are important and matter to you. In this way, the desired information will always be available on the shelf, just like the sugar you want for your tea.
Anatomy of Human Memory Storage
The parts of the brain which serve as information processors to create memories and store them include the prefrontal cortex, neocortex, basal ganglia, cerebellum, hippocampus, and amygdala. These different parts of the brain have different functions associated with various types of memories.
This part of the brain serves its purposes as a store for short-term memory. The prefrontal cortex consists of two functional sides the left and right. Both of the sides collectively serve short-term working memory.
This is part of the brain serves as an information processor. This is the part of the cerebral cortex which is involved in reasoning and learning. It is said that neocortex extracts information from the explicit memories stored in the hippocampus to create reasoning and logic.
These are present deep within the brain which keeps the memories that are implicit and provide automatic or involuntary learning from the information provided to the brain in the past.
This is located on the temporal lobe; this is one of the most important parts of the brain which serve for the memory function. Amygdala is known to create sentimental and emotional responses which are then linked to the memories. This helps in the creation of long-term episodic memories.
The temporal lobe of the brain holds this small structure which holds an enormous list of function. This is crucial for the creation of long-term memories. It acts just like a catalyst for long-term episodic memories. Hippocampus is also essential for short-term memory storage. If the hippocampus gets damaged or surgically removed, like the famous case of Henry Molaison, the brain becomes incapable of forming new memories and store them.
Types of Memory
Any information that gets stored in the brain either temporarily or permanently becomes a memory. We can roughly classify memories on the bases of their time duration which they experience in our brain as well as, the classification is also based on the ability of the brain to recall them.
As described earlier, information enters the brain through sensory organs. These organs are eyes, ears, nose, and skin. Sensory memory is created as soon as the information perceived by these organs reaches the part of the brain which processes the information. The processing of the sensory information and its conversion to memory is a complex but immediate process. Sensory memory only stays in the brain for as long as one to two seconds. During this period of a second, information of the object is processed, and the brain recalls previous memory of the objects similar to it. This process of recalling enables the brain to identify the object and name it. If the object is something unique it gets stored or passed on to the comparatively longer storage memory type.
Let us simplify this by an example. Like every normal day, you are driving home. You are watching cars ahead of you. Your eyes are perceiving cars and vehicles in front of you. The general size of the car and the size you are currently observing creates sensory information which gets projected into your consciousness as the distance between your car and the car next to you. The perception of color is one of the main sensory functions of eyes. This information tells you that the car in front of you is just a red car. You will probably forget to see a red car on your way back home because every day you see a lot of red cars. The whole sensory information is processed by your brain so you can drive back to your home. The not so important information is discarded into the pits of your brain in just a mere second. But it is said nothing ever gets deleted from the brain it is just discarded to the lower levels just like useless stuff in the storeroom. But it always stays there.
The study and understanding of memory in human beings is a complex and confusing process. Some scientists consider short-term memory and working memory the same thing. However, some other references lead to the belief that they are two different scenarios.
Short-term memory is an intermediate type of memory and storage. The most appropriate and reasonable thing will be considering short-term memory and working memory as ”closely related”.
Short-term memory deals with storing the processed information which passed the level of sensory memory. When the information has passed the sensory level, we can accept the fact that the brain now completely understands the subject. However, in short-term memory stage priority of the subject and the information regarding it is decided. The capability of the brain to store information stretches from few seconds to minutes. After that, the memory and information become unclear as it gets faded away down the priority list as new information keeps entering the brain.
Short-term memory can be understood by a simple example. When someone tells you their address or phone number it stays in your mind only for a few seconds after the numbers start changing place as your brain is processing new sensory information. So, to not lose it completely you jot it down. That is a simplified way to tell how short-term memory works.
Short-term memory and Working memory
The short-term memory and working memory are closely related. This relationship can be understood by understanding what working memory exactly is. Working memory is an active process of storing information and holding on to it. It is a little or a moderate piece of information that is considered important by our brain.
This process can be simplified by a simple example. Whenever you go shopping you do not always make a list. You simply observe the things which are required and make list in your short-term memory. However, this list is considered important, so your brain holds on to it for a longer period. This period stretches to hours.
There is a slim chance that you still remember the things you bought from the grocery store last week.
Working memory is mostly considered as the ability of the brain to recall the objects which were subjected to short-term memory. That is why working memory is considered as an active process which happens voluntarily, in most cases. On the other hand, short-term memory is like sensory memory which is a continuous but passive process. The information which gets discarded by the brain on the level of short-term memory does not get faded as much as the memory or information which gets discarded from the sensory memory stage.
Long-term Memory Storage
Unlike short-term memory, long-term memory has a very large span of storage. Moreover, the storage capacity I.e. the amount of information which can be stored is almost unlimited. The information sometimes reaches long-term memory storage and it gets stored there for the whole lifetime.
Some particular pieces of information make their way into long-term storage very easily. You do not need to consciously or forcefully put our attention on it, but they reach into the planes of long-term memory storage without even bothering you. And sometimes you need to repeat a piece of information to make it reach your long-term memory.
Let us take a simple example, you will always remember your first date, your wedding day, or your last day at school/college. The memories are so deep and clear that most people can even recall minute details of a particular day or event. Contrary to this scenario, you have to cram, repeat, and do multiple rehearsals of your course to pass your exams. This lays the foundation for two particular types of long-term memory types.
This type of memory is the name of earlier example long-term memory storage, where the important days or events which happened in our lives will always remain vivid and clear as a day. The episodic memories are composed of pieces of information that have a very high sentimental value, they are of the highly emotional events, and the sentimental value of the particular event associate all the other memories surrounding that specific timestamp get engraved into the long-term memory.
This is referred to as the later example of memory. This is the long-term memory that becomes long-term by the continuous repetition of particular information. For example, your continuous repetition and exposure to important phone numbers get them into your long-term memory. And you can easily recall them whenever you need them.
Human Memory Storage Models
Models are one of the main essences of biology. The models under the scope of this writing are worth mentioning, as they have tried the possible best to explain the complex human memory system.
Atkinson-Shiffrin Memory Model
This is a very simple model describing how information finds its home in long-term memory storage. According to the Atkinson-Shiffrin Memory Model, the only possible gateway a piece of information has to reach the planes of long-term memory is by its rigorous repetition. However, this idea of reaching long-term memory through rehearsals was denied as there are scenarios when a person remembers an event, which happened only once, for his whole life.
Working Memory Model
This model is rather complex which claims to have several components and each component plays a different role in the processing of information and preservation of memories. Working Memory Model is was proposed by Baddeley and Hitch. It is an actively working model that is more focused on short-term memory storage and recalling the information stored in short-term memory storage. This model has three integral components that act as stores, one is called central executive, the second one is known as the phonological loop and the third most is considered the visuospatial sketchpad.
The central executive is related to processing the information. The other two manage visual and auditory information.
This model proves the fact that it is hard to hear or visualize two different things at the same time, rather than using the ability to hear and seeing each on two different subjects.
Memory storage is the process by which the brain can store facts or events so that they can be helpful in the future. It is the process by which life experiences are stored and different skill sets are learned and retained in the brain.
Our brain is continuously involved in the process of memory storage. It receives several pieces of information even within a second, processes them, and stores valuable information in the form of memory.
Memories are stored in the brain at different levels. Those stored at the lower levels are easily forgotten while the ones stored at the higher levels are retained for a longer time.
Our brain acts as a storeroom where memories are stored. Memories related to the things we are more interested in are rapidly stored and remain there for a much longer time.
Different areas of the brain are involved in the process of memory storage. These include;
- Prefrontal cortex
- Basal ganglia
Based on the time for which information is stored in the brain, memories are of following types;
- Sensory memory is created when sensory information is received and processed by the brain. It is either associated with some previous memory and is stored or is either discarded after its processing.
- Short term memory is the one which is stored in the brain for some seconds to minutes
- Working memory is a type of short-term memory that is considered important by the brain and stored for some time until a task is performed
- Long term memory is stored for months to years. It includes memories about facts and life events as well as memories related to some skills such as writing, typing, etc.
Different models have been proposed to explain the process of human memory storage. The two most famous are the Atkinson-Shiffrin model and the working memory model. A brief detail of both these models has been discussed earlier in the article.
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