Perception is the beginning of human cognitive development, and then memory, from mechanical memory to abstract memory. According to the growth of people's age, the cognitive stage is divided into four stages:

The first stage: perceptual movement stage, 0-2 years old.

This stage has the following characteristics: the object is permanent (the immediate thing is there), thinking is budding, and intuitive action thinking is the main thinking form.

The second stage: preoperative stage, 2-7 years old.

The cognitive characteristics of this stage are: symbolic function (literacy), irreversible thinking (I have a younger brother and my younger brother has no older brother), egoism, inability to obtain conservation relations (quantity and volume) and animism (animism).

The third stage: specific operation stage, 7- 1 1 year.

The main characteristics of children's cognition at this stage are: reversible thinking (I have a younger brother and my younger brother has a brother), self-centeredness, conservative relationship and concrete logical thinking.

The fourth stage: formal operation stage, after 1 1 year.

At this stage, tangible things are tied with thinking, which frees the form from the content and enters the stage of formal operation. The main features are: understanding the relationship between propositions, hypothetical-deductive reasoning and abstract logical thinking.