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.