Physiologically, LucianFreud called this desire "infantile amnesia" in which children's memories disappeared before they were three years old, which was actually caused by immature brains.

Hippocampus is mainly responsible for memory in the brain, but before the child is three years old, the cerebral cortex and hippocampus are not mature, and the main storage of memory depends on the connection between neurons. The number of neuronal connections in children can only reach its peak at the age of two or three, which can be said to be twice that of adults, but a large number of neurons will only consume the energy of the body. In order to keep a balance, children after the age of four will lay off employees, and those unnecessary contacts will be clearly omitted.

The storage capacity of hippocampus is also limited, and new memories will overwrite old memories, which is also the reason why children can't remember memories before the age of three.

2. language.

Children's memory is closely related to language and logic. Before the age of three, children can't speak fluently, express clearly, let alone logically, so it is difficult to preserve their memories.

This is because children don't fully understand words, can't understand mistakes before the age of three, and can't objectively describe events, so they can't mark these things as memories in their own minds, and eventually they will lose these memories.

3. Personality.

As children grow older, they will also realize that they have experienced many things, and their self-awareness begins to sprout, but it is the awakening of self-awareness that will stimulate them to store memories.

In fact, everyone will experience this kind of thing. A thing that has nothing to do with yourself will not be remembered for long, but a thing that has something to do with yourself will be remembered deeper. Therefore, after one and a half years old, they do have memories, but these memories are limited and self-centered, which is also the basis of children's personality development.

Restriction means that children do have memories before the age of three, but they will begin to forget when they are six. Egoism means that with the awakening of self-awareness, children will begin to build autobiographical memories, which can be preserved for a long time.

Although a child's memory will disappear before the age of three, experience will have an impact on the child. In this regard, Dr. Montessori once pointed out that human beings have two fetal periods. The 1 fetal period in the mother's womb is called the physical fetus, but the second one is called the "mental fetus" in the early postnatal period, which is also the key stage of children's mental formation.