We may classify social groups from various viewpoints. If we consider size as the criterion, the single person as a focus of group relationship is 'monad' two involved in interaction to affect its organization is 'dyad' and 'triad' with the participation of three. If we consider the nature of social contact and intensity of social interaction the types of social group will be as such:
The primary group is primary in the sense that the members are emotionally attached together sharing their basic ways of life with one another. In the basic affairs of life which are most essential for a social life those who fall into mutual sharing of one another form a group prime in importance called primary group. Emotions, attitude, ideas and habits of individuals develop within here.
The people within their contact second to the primary form secondary group no matter whatever the type of relationship is there. The intimacy is relatively lower than that in primary. The relations of teacher and student, buyer and seller, voter and candidate, are secondary. The frequency, duration, intensity and focus in interaction may be there but their degree being lower than the one in primary group. This is second in importance of life to the participants. He is first affected by the primary group members and later by those in the secondary.
In-Group and Out-Group
These types were given by W. C. Sumner.
During the processes of our daily life we divide people into 'we and they'. The interest of the individual rests within those people with whom he is closely affiliated and places his confidence in them. They may be Members of his family, neighborhood, play-group or immediate or close relatives. He develops his subjective attitude and forms opinion about the acceptance or rejection of a certain object or idea through his in-group members. Consciousness kind also falls in this type of social group. The members are tied in the bonds of 'we feel', It is the group to which the individual is member.
'Out group' members are considered in relation to in-group. Those not included in 'we' and fail in `they' are the members of out-group, its members are not members of individuals self. We (in-group) the Russians, they (out-group) the Americans: we the Pathans and they the Sayyed are the examples. It means a person member of a certain group falls in its in-group and a person not member to a group falls in his out-group.
Formal and Informal Groups
Here membership is defined. Those who fulfil the conditions can become member. The entry is made under written rule and the membership can be cancelled on violation of its rules and regulations. The offices are distributed according to the rules. The students in a class are a formal group, other example is the Union Council, people enjoying a match on tickets. United Nations Organization (U.N.O.), SAARC, Punjab Professors and Lecturers Association (PPLA), Youth Club in a mohalla, are also formal groups.