Why do some memories last a long time and others disappear easily? We will explore the mystery of the expiration date through the mechanism of memory formation and storage.
People say, “Man is an animal of forgetfulness. Some memories stay deep in someone’s mind, but some disappear in a few hours. This is a phenomenon that can be easily observed in our daily lives. For example, the content memorized just before a test disappears from one’s mind as soon as the test paper is received, and on the other hand, trivial memories from several years ago suddenly come to mind. Thus, memory is so variable that it is impossible to predict, and this characteristic has a significant impact on all aspects of human life.
Humans can learn because they can remember, and because they can learn, they can live like humans. Memory and learning are intimately linked and deeply related to our survival. For example, the ability to remember certain risk factors or survival skills is an important tool for keeping our lives safe. If you ask people to specifically recall what it is like to remember, they will find that it is not an easy task. Someone with a strong literary imagination might think of a drawer in their head, while someone else might think of their brain. But if you go beyond that, most will find themselves limited in their understanding of the specific mechanisms of memory.
So what is the principle of how humans can remember something, and why is there a difference in the validity period of memory? To understand this question, we must first look at the structure of the brain and nervous system. Before we look at the mechanisms of learning and memory, we need to look back at the simple biology we learned in high school. Everyone would agree that memories are stored in the brain. Since the brain is part of the central nervous system of our body, we need to know about the “nervous system”. The nervous system is a system in the body that receives internal or external stimuli, transmits signals, and is responsible for making judgments and responses. It is through the nervous system that memories are processed and stored.
The structural and functional unit cells that make up the nervous system are called “neurons,” and in simple terms, it can be said that signals travel through pathways called neurons. In front of the neuron there is a neuronal cell body that is involved in the metabolism of the neuron, and there are dendrites that receive signals in the neuronal cell body, and at the back of the neuron there are axon processes that extend like a tail. This structure allows signals to travel quickly and efficiently, and as a result, humans can remember and store different types of information.
Signals for stimuli travel in a chain, being conducted within a single neuron and then transmitted to the next neuron. Within a single neuron, electrical signals travel due to the difference in ion concentration between the inside and outside. What we should pay attention to this time is the transmission process between neurons. The gap between the axon hillock of the pre-neuron (sleeper neuron) and the dendrite of the next neuron (post-neuron) is called “synapse”. The transmission process that takes place at the synapse is one of the key mechanisms of memory formation, and if this process is not carried out efficiently, the memory can quickly disappear or be distorted.
The scientist who discovered the mechanism of memory is Eric Richard Kandel, who won the Nobel Prize in Physiology or Medicine for his work. His research showed that memory involves more than just storing information. Kandel used an animal with a simple neural circuit, the sea hare, as an experimental subject and analyzed the process of memory formation from a molecular biology perspective. This experiment clearly demonstrated the difference between short-term and long-term memory. Kandel discovered that learning and memory can be strengthened by simple repetitive training.
In short, short-term memory is merely a functional change related to chemical secretion, while long-term memory is an anatomical change in which the shape of the cell itself changes. It can also be seen that in order to turn short-term memory into long-term memory, the same stimulus must be repeated, just as the tail of the sea hare was stimulated many times. In other words, this proves that “repetition learning” is scientifically effective. When we learn something repeatedly, the information is stored in long-term memory and remains there for a long time. This explains why repetition is important when studying for exams or learning a foreign language.
Because long-term memory increases the number and structure of synapses, we can now imagine a network of neurons that becomes increasingly complex as we remember. Like a branching tree, our memory grows and changes with repetition and stimulation. Memory is not just a process of storing information, but an important phenomenon that shows how our experiences and knowledge evolve and strengthen over time.
