For many people, remembering one thing is not difficult. But it is strange that in a person’s life, whether you like it or not, the two sides of your memory will be at a blank stage, one is amnesia in old age, and the other is amnesia in adult childhood. Amnesia in old age is easy to understand. After all, many physiological functions will be degraded after entering old age, but it is difficult to understand when children also suffer from amnesia.
Everyone knows that childhood can be said to be the most precious period of learning. Complex skills such as language and walking are learned during this period. Studies have even shown that babies start thinking training in their mother’s womb. Therefore, it should not be difficult for children to remember some things, not to mention that these things are precious. Who doesn’t want to remember the first words he said, or the first friend he made? So, where are our childhood memories lost?
There was a long-standing view that children cannot form stable memories before the age of 7, so forgetting is inevitable. But a series of experiments after 1980 showed that children started to remember things as early as 3 years old. At 6 months of age, the baby’s memory can last at least one day; by the age of two, it can remember things from a year ago.
In 2005, researchers discovered that children as young as four and a half years old can recall in detail a trip to Dinis 18 months ago; at five and a half years old, they can remember 80% of three-year-old memories. It’s about 7 and a half years old that children begin to forget many early memories, and can only remember 40% of their childhood life.
These studies show that children are not unable to remember because they do not have developed memory skills, they can also create memories and can retrieve memories. But it is strange that these memories will disappear quickly after the age of 7. As a result, researchers began to focus their research on what makes memories disappear, rather than whether children can remember things. They found some influencing factors, such as language ability and self-awareness.
Researchers have found that language ability can affect childhood memory. An experimental team once interviewed children in the accident and emergency department. These children did not suffer from any serious illness, but were slightly abrased during play. The researcher asked them how they bruised at the time and recorded the children’s responses. Five years later, the researchers interviewed these children again, and found that those children who were able to describe what happened in words at the time can recall them again after five years. Those children who couldn’t tell the whole thing at that time had trouble remembering it, or simply forgot about it. This research shows that if early experiences are not translated into language, they may be lost. From 1 to 6 years old, children have made major breakthroughs in language skills from being able to speak a single word to being able to speak fluently. At this time, children’s memory abilities are also increasing.
Related to language is another ability-self-awareness. Children start to say “you” and “me” when they are about 18 months to 24 months old, indicating that they have initially formed a sense of self and realize that they are different from others. Researchers found that in cultural environments that pay more attention to themselves (North America and Europe), these cultural traditions pay more attention to children’s personal experiences, preferences and emotions, rather than their relationships with others, or social rules and behavior standards. Of adults will have earlier and more detailed childhood memories than adults in Asia and Africa. For example, the average age of the earliest memory of European descent is 3.5 years old, Maori in New Zealand is 2.7 years old, and East Asians are 4.8 years old.
There is no doubt that good language and self-awareness can enhance memory ability. But beyond that, what else will affect our childhood memories?
Researchers have noticed a phenomenon that people do not forget all the things in childhood. For example, in childhood, if they learn to walk, swim and ride a bicycle, they will not forget them. In contrast, what people tend to forget are those episodic memories related to long-term memory, such as past experiences and events. In the long-term brain memory, the hippocampus plays an important role. The hippocampus is located in the temporal lobe of the brain and is closely connected to the limbic system of the brain. Filtered information is temporarily stored in the hippocampus for a few minutes to a few weeks, and important sensory information is transmitted by neurons in the hippocampus To the long-term memory area.
Babies will form 700 new neuron connections every second. So, is there something wrong with these neurons?
To study the correlation between neurogenesis and forgetting, a research team at the University of Toronto conducted a test. First of all, rats will be trained to be very scared of mild electric shocks. Then, some adult rats will be placed in an environment where they can step on the wheels. When they return to the electric shock environment again, the adult rats have largely forgotten their fear of electric shock; but those rats that have not stepped on the wheels still remember. Live the connection between the shock environment and fear. So why did adult mice forget their previous fears? This is because pedaling on wheels has been shown to increase the activity of neurons. In other words, new neurons in adult mice may interfere with previous memories.
The researchers conducted another experiment with young mice. Young rats will take some drugs every day that slow down the growth of neurons. According to the first experimental result, if memory is related to the growth rate of neurons, after the young rats swallow the drug, as the growth of the neurons is inhibited, they should have better memory than the young rats without the drug. Finally, the research results confirmed this hypothesis.
These studies have found the real culprit for stealing childhood memories-the new neurons.
Researchers speculate that as mammals grow up, there are two areas of the brain that are not found in other animals that continuously produce neurons. The dentate gyrus in the hippocampus is one of them, and new neurons are continuously generated in the dentate gyrus. , These new neurons fiercely compete for territory, change pre-existing neuronal connections, establish new neural connections, and severely disrupt the brain circuits that store old memories. Most of these early connections will eventually be “pruned”. Cause it to be destroyed, so that this part of the memory is forgotten.
Before the age of 7, this “turf battle” was particularly fierce, but as we age, nerve formation will slow down. Around 7 years old, the hippocampus of the brain has achieved a relatively stable neuronal connection, and people can begin to save Episodic memory.
So, can we retrieve our childhood memories? It seems unlikely at the moment. Some old neuron connections may have been “pruned away” and cannot be restored. Even if some early memories have withstood the cyclical turbulence of brain growth and decline, they may also be deformed. We should not trust these memories too much. In 1995, researchers conducted an experiment in which they told volunteers some of their own childhood stories (these stories were collected from volunteers’ relatives and friends). What the participants didn’t know was that there was a story in it. It is a fictitious researcher. This story tells that they once lost in the mall before the age of 5. However, a quarter of the participants believed that this was what happened in their childhood, and even though they were told that the story was fabricated, some volunteers still insisted. This experiment shows that the childhood experiences that some people think they can recall may be mixed with many other people’s stories or fantasy elements and are not real.
As neurons are constantly being added, it is impossible to prevent some existing memories from being forgotten, and we may inevitably lose childhood memories. But if you lose, you will gain. Without such a flexible and malleable brain, young children will not be able to show amazing learning and memory abilities.