Types Of Memory: How Does The Human Brain Store Memories?
What we commonly know as memory (remembering something) is usually a general concept, because we usually talk about memory long-term.
But there are other types of memory, such as short term memory and the sensory memory, which participate in the formation of this more lasting memory. In fact, through several decades of scientific research, it is known that these different varieties of memory follow different logics and are based on different parts of the brain. Let’s see what its characteristics are.
If we start to reflect on the capabilities of the human being, It is very possible that we will come to the conclusion that our species is characterized by having a good memory Every day we learn and memorize things about the environment in which we live: who is the new president of a distant country, where can we find a national park whose photos have surprised us, what is the meaning of a word that we did not know, etc.
Compared to ours, the memory of other animals seems to be smaller. After all, they do not have a language from which to memorize complex concepts that refer to elements that they have not seen directly. But… surely memory is just that?
After all, many migratory birds memorize the places they have to pass through to travel thousands of kilometers each year on their journey from North to South and vice versa. In the same way, salmon memorize the point in a river where they have to spawn and arrive there, after much effort and having spent a lot of time in the sea. Aren’t these examples proof that there are different types of memory?
The types of memory, summarized
The different memory types They have their particular way of functioning, but they all cooperate in the memorization process. Memory helps us adapt to the environment and marks us to define who we are; our identity. Without it we would be incapable of learning, nor could we make sense of our surroundings or ourselves.
On the other hand, the information that the memory “files” is not stored without being altered; It is constantly changing, although we do not realize it. However, the contents that we memorize are altered through somewhat different mental processes, in the same way that they are assimilated and internalized by the brain in different ways.
But, What types of memory exist? What are the phases of memory? Below we will answer these questions and explain how human memory works and how it allows us to remember events, data, experiences and emotions that we have experienced in the past.
First research on memory
The first research on memory has its origin in studies of Hermann Ebbinghaus a German psychologist who at the end of the 19th century attempted to decipher the fundamental laws of memory by studying meaningless syllables (BAT, SIT, HET).
Ebbinghaus’ theory of memory
One of his most notable achievements was the demonstration that higher mental functions could be studied scientifically in the laboratory. He also concluded that there was a “forgetting curve,” which shows the deterioration of memory with the passage of time from the moment of learning. Besides, formulated a theoretical model in which he argued that the memory mechanism requires repetition so that the data we remember are associated with each other.
Bartlett takes the study of memory outside the laboratory
Ebbinghaus had his approach used for many decades, what was called “the verbal learning tradition,” but in 1932, Sir Frederick Bartlett He began his studies on the functioning of memory in natural environments (Ebbinghaus carried out his studies on memory in the laboratory), giving rise to a new paradigm. Bartlett, instead of using meaningless syllables, used stories, and introduced schema theory to his research to explain their influence on memories
Furthermore, he proposed that human beings remember through a general impression with some details, and that from such components they build a version considered close to the original; memory works with schemes, not with faithful replicas. Although it was criticized for its lack of methodological and statistical rigor, it stands out for its adherence to the constructivist theory of memory and for its contributions to the cultural formation of memory.
Miller and the current paradigm on how we store memories
Two decades later, in 1956, George Miller showed that people can retain 5 to 7 items at a time in short-term memory. These elements can be a simple letter, a number, a word or an idea. Currently, there is a certain consensus in cognitive psychology stating that a person interprets information thanks to prior knowledge of it, and thus builds memories of it. That is why it is important to highlight that Not all experienced events are stored, as there is a selection of relevant events, and what is not interesting is eliminated. Furthermore, the events experienced undergo a process of structuring and interpretation and, therefore, what is remembered is a perceived reality.
Experts in the study of memory agree that the memory process involves not only the cerebral cortex but other brain areas also participate in this process, for example the limbic system It has also been shown that the left hemisphere processes verbal information, and the right hemisphere processes visual information. The ability to retain words is less than that of remembering images.
Memory phases: encoding, storage and retrieval
As Brenda Milner demonstrated after her research with patients with memory disorders, it is not located in a specific place in the brain, but rather consists of several systems that allow what is known as the three phases of memory: the codinghe storage and the recovery.
Classification and types of memory
There are different types of memory, and William James (1890) was a pioneer in formulating the distinction between these, since concluded that primary memory and secondary memory existed
Later, the so-called multi-store theory by Richard Atkinson and Richard Shiffrin appeared, which understands that information passes through different memory stores as it is processed. According to this theory, We have three different types of memory: the sensory memory the short term memory (STM) and the long term memory (LTM) James’s primary and secondary memories would refer to the MCP and MLP respectively.
The sensory memory which reaches us through the senses, is a very short memory (lasts between 200 and 300 milliseconds) and immediately disappears or is transmitted to short-term memory.
The memory information remains long enough for it to be selectively attended to and identified so that it can be processed later. Thus, its usefulness has to do with the here and now, everything that happens in the present moment and to which we have to react in real time. The information can be visual (iconic), auditory (echoic), olfactory, etc.
short term memory
When information has been selected and attended to in sensory memory, goes to short-term memory, also called operational memory or working memory Its capacity is limited (7+-2 elements), and it performs two functions. On the one hand, it maintains information in the mind when said information is not present. On the other hand, it can manipulate this information, allowing it to intervene in other higher cognitive processes, and therefore, it is not a mere “memory drawer.”
Baddeley and Hitch, in 1974, instead of calling it “short-term memory”, called it work memory due to its functional importance in cognitive processing, as it allows the fulfillment of cognitive tasks such as reasoning, understanding and problem solving. Through this concept, the idea that long-term memory depends on short-term memory is abandoned, and this type of memory is fragmented into four subcomponents:
long term memory
The long term memory It allows information to be stored permanently, and we can classify it into implicit and explicit memory.
Implicit memory
The implicit memory (also called procedural) is stored unconsciously. It is involved in learning various skills and is activated automatically. Riding a bicycle or driving a car would not be possible without this type of memory.
Explicit memory
The explicit or declarative memory, is associated with consciousness or, at least, with conscious perception. It includes objective knowledge of people, places and things and what they mean. Therefore, two types are distinguished: semantic and episodic memory.
