WHAT IS HUMAN MEMORY? (PSYCHOLOGY) - NEUROPSYCHOLOGY - 2025

The memory human is a function of the brain that allows humans to acquire, store and retrieve information about different types of knowledge, skills and past experiences. It is one of the most studied human functions in Psychology.

Think for a moment about all the activities you carry out in your day to day: walking, talking, reading, cooking, working, driving… All of them have required prior learning that you could not carry out without the psychic faculty of memory.

According to the Royal Spanish Academy, memory is a psychic faculty by means of which the past is retained and remembered. It is a basic and essential function in your life, because it is present in all the activities you do on a daily basis.

Definition, characteristics and meaning of memory

According to the astronomer Carl Sagan, the human mind is capable of storing a quantity of information equivalent to ten billion pages of an encyclopedia.

But memory is not a perfect storage system. Although on many occasions human memory is compared with the storage capacity of a computer, the differences are in the way of recovering the memories or saved files.

The computer recovers a file without any modification or change, regardless of when it has been stored; while the memories recovered from the memory can be altered and modified by many factors.

Memories can be influenced by other memories, by the reception of new information, by the interpretation you can make of what happened, by your creativity, by your ability to invent…

It can also happen that you modify the memories to fit your expectations, resulting in memories that contain errors and distortions.

This ability to modify memories can go so far as to unconsciously generate false memories. This possibility is found much more frequently in children compared to adults.

Memory, although it does not keep literal copies of what has happened as computers do, it is a reliable system that allows you to remember quite accurately.

Regarding the location of memory, there is no specific physical place where it is located, but it is distributed by different locations of the brain.

In this way, we can find the different types of memory, which we will see below, located in the prefrontal cortex, temporal lobe, in the hippocampus, in the cerebellum, in the cerebral amygdala, in the basal ganglia…

Memory types

There are many knowledge errors that the population handles daily, erroneous beliefs that have expanded over time and that are believed to be true.

Something similar happens with memory, which is conceived as a unitary and indivisible system. As we will see below, this belief is erroneous, since memory is made up of a set of very different memory systems or subtypes that are each in charge of a specific function.

For this reason, the expression: "I have a very good / bad memory" is not correct, but it is most likely that you are good or bad in some of the memory subtypes that make up memory and not in memory as a whole.

In Tulving's words, each memory system:

"is an anatomically and evolutionarily different structure from other memory systems and is differentiated by its methods of acquisition, representation and retrieval of knowledge."

Memory is divided into three memory systems or subtypes: sensory memory, short-term memory, and long-term memory.

- Sensory memory

Sensory memory is responsible for registering the sensations that are perceived through the senses and for superficially recognizing the perceived stimuli.

This memory system has a great processing capacity, as it is responsible for recognizing perceived sensations and recognizing the physical characteristics of perceived stimuli such as lines, angles, brightness or tone.

Sensory memory is a memory system or subtype that in turn is made up of two other subtypes:

• Iconic Memory: it is the memory system in charge of recording visual stimuli and has a retention capacity of around 300 milliseconds.
• Ecoica memory: it is the memory system in charge of temporarily storing auditory stimuli when they disappear and has a greater retention capacity, around 10 seconds.

Although sensory memory is a transitory system, of very short duration, thanks to this system you are able to remember the sounds you have just heard and the details of the images you have just seen.

- Short memory

Within short-term memory we find two memory systems: short-term memory and working memory or working memory.

Short term memory

It is a passive storage memory system that is characterized by the ability to retain information for short periods of time.

Its storage capacity is limited, approximately 7 plus minus 2 items for 18-20 seconds if the retained information is not reviewed. For this reason you are able to remember a phone number for a few seconds and after a few moments you forget it.

The number of elements can be expanded if simple elements are grouped into higher order organization units, that is, you can remember more elements if you regroup simple elements together, if you make groups of elements.

In this way, you will remember seven groups of elements that in turn contain simple elements, so the number of elements remembered will be greater.

In order for information to remain in short-term memory for more than ten seconds, you must review the information. If it is not reviewed, the information will end up disappearing and you will be unable to remember it.

However, when the review is sufficient, the information found in short-term memory is transferred to long-term memory.

So if you want to remember a phone number that you have just been told, or any other item, you must review it mentally until you learn it, which will mean that the information has been transferred to long-term memory.

Working memory or operational memory

It is an active memory system that maintains information temporarily during the organization and execution of a task.

That is to say, working memory allows you to retain and manipulate the necessary information so that you can face the demands or tasks required.

Although its storage capacity is limited, thanks to this memory system you can perform several mental tasks at the same time, such as understanding, reasoning, retaining information, acquiring new knowledge and solving problems, among others.

Working memory or operative memory is closely related to long-term memory, which provides you with the information you need to perform tasks.

If you stop to think, working memory is involved in any type of mental activity, such as reading comprehension, mathematical operations, the organization of tasks, the establishment of objectives…

As with sensory memory, working memory is also made up of memory systems or subtypes, specifically it is made up of the central executive and two subordinate systems: the phonological loop and the visuospatial agenda.

a) Central executive: it is the most important system in working memory, it is the system that is in charge of supervising, planning, organizing, storing, processing, making decisions, executing tasks…

The central executive is also responsible for coordinating the phonological loop and the visuospatial agenda, at the same time that he is in charge of manipulating the information in order to be able to face the demands, the tasks that you have to carry out at all times.

The central executive is the type of memory that allows you to set goals, plans, change tasks, select a stimulus, inhibit a response…

b) Phonological loop: also called verbal working memory, it is the memory system specialized in storing and manipulating the verbal information

that you receive.

Thanks to this system you have learned to read, you have learned to understand the meaning of what you read, you have learned new words, a new language…

c) Visuospatial agenda: it is the memory system specialized in storing and manipulating the visual or spatial information that you receive, that is, the visuospatial agenda is in charge of creating and manipulating mental images.

Thanks to this memory system you can orient yourself geographically, plan spatial tasks and understand texts.

Both the phonological loop and the visuospatial agenda have a limited storage capacity and are capable of modifying the information received.

Working memory helps us to carry out many of the tasks of our daily life, such as: to organize the tasks that you have to carry out each day, to check if you have been charged well for coffee, to read the signs while driving…

- Long-term memory

When you talk about memory in general, you mean long-term memory, which is responsible for storing your memories, the knowledge you have about the world, the images you have seen, the concepts you have learned…

Within long-term memory we find declarative memory or explicit memory and procedural memory or implicit memory.

Declarative or explicit memory

This memory system refers to the events that you can consciously and intentionally remember and is divided into two new subtypes:

a) Episodic memory: also called autobiographical memory, it is in charge of storing your own experiences, what happens to you.

When a friend asks you what you did last weekend and you tell him all the plans you made, who you were with and how you spent it, you are using episodic memory to answer because you are talking about what you have experienced in the first person.

This memory system is the first to be damaged in older people.

b) Semantic memory: it is responsible for storing the knowledge you acquire about the world, the knowledge you possess in general.

When they show you an apple and they ask you what kind of fruit it is, you are using semantic memory to answer, you are using the knowledge that you have acquired throughout your life to answer the question that has been asked of you.

Thanks to semantic memory you are able to associate words, symbols and concepts, you are able to know the capital of your country and the name of the president of the government.

Procedural or implicit memory

This memory system is in charge of storing the information regarding the skills or abilities acquired

Once a skill is acquired and consolidated in procedural memory, you move on to perform that skill unconsciously.

Motor skills, such as riding a bicycle or driving, can be stored in this memory system; cognitive skills, such as mental math; habits, like brushing your teeth; emotions, like a phobia…

As you can see, memory is made up of a complex network of memory systems or subtypes that interact with each other to acquire, store and remember all the information you receive.

How are memories formed?

You have just seen the different memory systems that exist. Now I am going to explain to you how they interact with each other in order to form memories.

When faced with an external stimulus, the first memory system that is put into operation is sensory memory, which is responsible for perceiving the sensations and physical characteristics of the stimulus with which we are interacting.

At this point, the iconic memory for the recognition of visual stimuli and the echoic memory for the recognition of auditory stimuli are put into operation.

The information received by sensory memory is sent to short-term memory, where it will be kept passively for a short period of time. So that the information is not forgotten at this point, it must be repeated.

In the event that we have to perform a mental task, the operative memory or working memory will enter the scene, which will be in charge of carrying out all the necessary tasks to meet the demands.

If the working memory is activated, the central executive, the phonological loop and the visuospatial agenda will be activated.

If information is repeated in short-term memory, it will be transmitted to long-term memory, where it will reside permanently as a memory. In this system the information can be altered, as we have seen previously.

This is the path that the information provided by external stimuli travels until it becomes memories in our memory.

Curiosities about memory

The German philosopher Hermann Ebbinghaus devoted many years of his life to the study of memory, reaching very interesting conclusions.

According to this author, forgetting occurs progressively, in such a way that a few days after having studied a material you only remember a small part of what you have studied, having forgotten most of the information learned.

Specifically, in the first 24 hours you can remember approximately 50% of the information learned; after 48 hours you can remember 30% and, after a week, you will only remember 3% of all the information you had learned a few days before.

To avoid this phenomenon, you must review the information studied with the aim of properly transferring it to long-term memory, thus avoiding its forgetfulness and consolidating its learning.

For this reason, it is advisable to study spaced out in time rather than studying intensively in a short period of time.

Another curiosity about memory is the primacy effect and the recency effect.

The primary effect and the recency effect refer to the fact that what comes first and last is more easily remembered.

That is, people remember the beginning and end of things better, forgetting more easily the intermediate content. This can be modified if the content in between has great emotional significance for the person.

For this reason we better remember the beginning and end of a telephone conversation, a reading, a song, a movie…

Conclusions

As you have seen, memory is not a single and indivisible unit, but a complex network of memory systems that interact with each other to acquire, store and retrieve knowledge, skills and past experiences.

Thanks to memory we can make sense of the world around us, remember past experiences, plan for the future and carry out all the tasks that give meaning to our day to day.

References

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5. Henson, RN Gagnepain, P. (2010). Predictive, Interactive Multiple Memory Systems. Hippocampus, 20, 1315-1326.