Memory is an amazing mental process that allows the brain to store memories. Depending on how the storage process is, memory can be of different types.
Among the many functionalities that this amazing computer has, which is the human brain, one of the most studied is memory, in all its variants. We will discover howthis phenomenon takes place, how we could classify its typology, and how it can be diminished.
- We recommend you read: “20 exercises to improve memory (for young people and adults)”
What is memory?
It is thebrain’s ability to encode the information of the present and its recovery in the short, medium or long term. What underlies this process is a series of synapses or neural connections, which depending on their level of excitement can generate a memory in a stable enough way to recover it in the future.
The other side of the coin in this process is the ability to learn, and that is that memory and learning, by definition, must always go hand in hand. If one is given, the other necessarily has to be given.
We can, therefore, describe the memory sequence through the following steps:
- Registration of information, or coding of data.
- Storage, whether for a few moments or over decades.
- Data recovery: the memory.
It is not an exclusively human ability, but it is true that the level of complexity of the nervous system of hominids, and of the human being in particular, is the highest existing in the entire animal kingdom. What does this translate into? In that in the rest of species we can observe to a greater or lesser extent an ability to generate memories and learn, but much less with the degree of intensity in which we do it ourselves.
Where are memories stored?
Once we know that we are constantly generating memories, we can ask ourselveswhere in our brain is the “hard drive” with all the experiences lived until today. The answer is simple: they are everywhere. This does not mean that each memory is stored throughout the brain, but that there is not a single structure dedicated exclusively to this task, but it is something shared by the multitude of sectors of this organ.
To get an idea of this complexity, let’s look at some of the areas and their involvement in memory tasks.
- Various areas of the cerebral cortex: they are responsible for housing the memories of our first years of life.
- Frontal lobes: this is where thoughts are generated.
- Center of the right hemisphere: here is the “dictionary” of all the words we know.
- Cerebellum: it is responsible for some of the learning that we have enhanced so much that they are already automated.
And these are just some of the areas. It takes the brain as a whole, with its more than 100,000 million neurons, to effectively perform the entire procedure.
How is memory classified?
Memory is a very broad concept and, depending on the characteristics of the specific process, we can establish a division that allows us to better understand each of the classes.
1. Sensory memory
It is the most primary of all, and is the one thatrecords the information we capture by the different senses, especially sight and hearing. Basically it would act as a warehouse, iconic in the case of what we see and echoic for the sounds we hear, to momentarily retain (just 250 milliseconds) the data we need before passing them to another type of different memory, the operational, which we will see later.
2. Short-term memory and working memory
Also called active or primary. It is the one we use continuously in our interaction with the environment. It allows us to retain the data (as long as we do not return to them) of about 7 elements (7±2, according to most studies) for about 30 seconds, before the information disappears from our brain. It would be something similar to the RAM of a computer.
We do not grasp all stimuli with the same ease. There are mechanisms that encourage the registration of some over others. For example, faced with a succession of similar elements, we are more likely to keep the first (primacy effect) or the last of the list (recency effect), to the detriment of those in the middle.
Sometimes we also find the term working memory to refer to short-term, but in reality they are somewhat different concepts, since while the MCP refers only to the storage of data, the working memory implies a treatment of that information to achieve an objective, so this would be a broader definition.
Let’s look in detail at the different parts that are involved in this type of memory.
Central Executive
It is located in the frontal lobe. Their task is tointegrate useful data and discard those that do not serve us. In addition, it will be responsible for connecting different processes of cognition that are happening at the same time in the brain.
Phonological or articulatory loop
It is responsible forpreserving for a few moments the verbal informationwe receive by ear, or by sight, since it transforms those images into the associated sounds. It is an essential part of the language acquisition process, whether first or second language.
Episodic buffer
Another store, in this case toconnect all the systems of workingmemory but also with long-term memory, the other great type that we will see in the next section of the article.
Visuospatial agenda
It would bethe working memory store associated with visual information. As with the phonological loop, anything we don’t actively retain will disappear in a matter of seconds.
3. Long-term memory
Surely, when we think about the concept of memory in general, what we are really thinking about is this modality. It is the one thatkeeps memories indefinitely in time inour neural networks. It is also called secondary memory or idle memory. This would be our hard drive, if we were a computer.
MLP can hold data from experiences lived over months, years, decades, or lifetime. The ability to recover them, before the phenomenon called forgetfulness is experienced, has to do with the strength with which the data was initially encoded as well as periodic recovery of them.
Within this modality, we can make a subdivision into two large blocks.
3.1. Declarative report
This type refers to the accumulation ofinformation relating to specific events. All this data, in turn, is distributed in two warehouses:
- Episodic memory: where the autobiographical memories of the events lived are found.
- Semantic memory: where we have memorized all the information related to our general knowledge. What you study and learn, for example.
3.2. Procedural report
It is a very different modality, but equally fundamental in our day to day. This is wherethe executive skills that have cost us so much to learn are recorded, but that over time become automatic. For example, driving, writing or dancing. Now you will understand the famous phrase: “it’s like riding a bicycle, you never forget”.
They are not only motor tasks, also included here are the cognitive skills that we have been acquiring, such as performing complex mathematical calculations that at first cost us a world and now we carry out “without thinking”, or what is the same, unconsciously.
To reach that level of automatism in the performance of a task it is necessary to go through three phases:
- Cognitive: the first times we try, we have to put all our attention on it, in a very conscious way.
- Associative: with repetition we develop automatic response patterns, keeping only the useful actions to meet the objective and discarding the rest.
- Autonomous: once the skill is perfected, we will do it without thinking about it.
Have you surprised yourself after taking many minutes driving, thinking about other things, without thinking about what gear you had to put in at that moment or when you should accelerate? Now you know the underlying process.
What are amnesias?
It is the most frequent alteration of memory, and is quantitative (memory loss will occur to a certain degree). Dementia, and especially Alzheimer’s, is one of the main causes of this disorder, although there are many others (trauma injury, stroke, substance intoxication, and others).
Amnesia can be partial or total, but also, depending on the chronological location of the affected memories, we can classify this memory impairment as follows.
- To know more: “Types of amnesia: characteristics, causes and symptoms”
1. Anterograde amnesia
The ability to generate new memories would be lost, but those before the injury could be evoked without problem. This is what happens at the beginning of the degenerative process of dementia.
2. Retrograde amnesia
With this type of pathology, the subject would experience aloss in their past memories, without prejudice to the creation of new memories.
3. Retroanterograde amnesia
This last typology would occur whenboth old and newly created memories are affected. It occurs, for example, in the final stages of senile dementia.
- We recommend you read: “The 5 differences between Alzheimer’s and dementia”
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.
