Phulel is a German physiologist and experimental psychologist. He systematically observes his children every day, from birth to three years old, and sometimes carries out experiments. He sorted out these records and wrote a famous book, Child Psychology, which was first published in 1882. The publication of this book laid the initial cornerstone for scientific child psychology.

Phulel's book is divided into three parts: the first part is about the development of sensation (about the development of vision, hearing, skin sensation, smell, taste and body sensation); The second part talks about the development of will (mainly about the development of action); The third part talks about the development of intelligence (mainly about the development of language). Until now, this classic book of children's psychology still has certain vitality and reference value.

The reason why Poole is regarded as the father of child psychology;

① In terms of time, the first edition of Child Psychology was published in 1882, which was the first book to study children's psychological development.

(2) Judging from the purpose and content of the book, scholars before Phulel did not take children's psychological development as the main research topic, but, like Darwin, studying children's psychology only provided the basis for evolution. The purpose of Child Psychology is to study children's own psychological characteristics and make a special discussion on children's physical development and psychological development.

(3) In terms of research methods and means, Phulel not only systematically observed and recorded his children every day from birth to the age of three, but also conducted scientific psychological experiments such as introspection.

(4) From the perspective of influence, Child Psychology was published. It has been highly valued by international psychologists and favored by peer scholars. Psychologists all over the world have translated it into more than a dozen languages and promoted it all over the world. Since then, children's psychology has developed. It can be seen that Phulel's child psychology has a far-reaching influence on the development of scientific child psychology.