Younger children are not stupid, they just think completely different ways, there are four stages of mental development in childhood. The sensorimotor stage, from birth to 2 years, the individual's feelings and actions. Understanding the world. Reflection exercise period (0-1 month): In this period the baby will give the response for any excitement like moving the head looking at the nipple and so on. After the child shows the initial reaction cycle, has some habit in the development process of this period, Piaget also proposed the concept of "circular reaction". The child begins to learn how to utter his voice and hold all objects that he can see, tries to calm down by touch and sight. The concept of preserved object began to appear at this stage. The child began to understand the relationship between targets, for example whether the parents always take the toy from the child. the child can shake hands with parents to express needs. In 12-18 mouths the child tries to create new formats, for example put the toy on the other side of the bed, the child will try to take it, but it is too far to take it, the result of this case is that the child gets found and pulls the sheet can help shorten the distance. The final sensorimotor stage is judgment, the child can know something without contact and