Group behavior characteristics 1, group members have the same needs and goals. 2. Group members have the same norms and behavior patterns. 3. Group members have the same sense of belonging. 4. Team members should communicate with each other. 5. Group members are organized. Group classification 1. According to the principles and methods, it can be divided into formal groups and informal groups. 2. According to the connection and development, it can be divided into loose groups, consortia and collectives. 3. According to the degree of openness, it can be divided into open groups and closed groups. 4. According to the size of social roles, it can be divided into reference groups and general groups. 5, according to the size can be divided into large groups and groups. 6. According to whether it actually exists, it can be divided into hypothetical group and actual group.