Child Psychology is an important work written by Piaget and Englishman Guerder. In this book, starting from "genetic epistemology", the author systematically investigates and studies the formation and development process of children's knowledge, and divides this process into perception; There are three stages in succession: exercise, surgery and pre-puberty.

The author makes a detailed analysis of various internal and external factors that affect children's psychological development at each stage, and has a large number of detailed perceptual experimental materials for demonstration. At the same time, it also points out the bias of traditional ideas in expounding their own views.

Piaget's research on cognitive development concluded that:

1, human knowledge originated from activities, and activities were internalized into reversible computing activities (inner activities).

2. There is a transitional stage of thinking in images and intuitive thinking between activities and specific operations.

3. The development of language and thinking goes hand in hand. The finer the thinking structure, the more language is needed. High-level operation structure is expressed in language.