Informal groups are in the third chapter of pedagogy. Informal group is a group with strong feelings, which is formed through mutual communication within formal groups and linked by personal likes and dislikes and hobbies. This group has no specific group goals and division of responsibilities, and lacks structural stability, but it has unwritten norms and natural leaders. Informal groups in class are mainly peer groups, and friends are more common.

The influence of informal groups on individuals mainly depends on the nature of informal groups and the degree of consistency with the goals of formal groups.

Formal organizations Formal organizations are organizations explicitly stipulated by the administrative department of education. Their members have a fixed establishment, clear rights and responsibilities, and have a certain organizational status. Classes, groups and league branches in the school are all formal groups.

The development of formal groups has gone through three stages: loose groups, joint groups and collective groups. Loose group means that students only form a group in space and time, and there is no purpose and content of common activities among members. Members of the joint group have already had activities with the same purpose, but the activities are only of personal significance. Collective is the highest stage of group development, and the common activities of members are not only of personal significance to each member, but also of important social significance.

We should constantly consolidate and develop formal groups, so that students in the class can form common goals and interests, produce common group norms, coordinate everyone's actions, meet the needs of members' sense of belonging and mutual recognition, and make the class a powerful group.