The factor which influences human life more than any other is that man lives in groups. He is the product of a group (mother and father); he is nurtured by a group (family or family substitute); and he spends all his life, unless he chooses to be a hermit (隐士), interacting with and within groups of various kinds.
The type of group most important to man is one in which the members are personally involved with each other on both an emotional and physical level, in which relations are characterized by informality, and in which these relations are stable and durable. Such a group is known in sociological terms as a primary group, and its foremost example is the family.
In small, non-technological, homogeneous societies, with members ranked on a more or less equal footing as to wealth, status, and privilege, the type of relations prevalent within a primary group exist at the level of the entire society. Such a society is referred to as a communal (共同的) society.
In large, heterogeneous (混杂的), technologically advanced, competitive societies, where division of labor is practiced, and where consequent inequalities exist in wealth, status, and privilege, it becomes necessary for individuals to expand their interaction to secondary groups. Members of a secondary group do not tend to be emotionally involved with each other. Relations are mostly formal and partial since the members come together for a definite and temporary reason. Teacher and student, merchant and customer, doctor and patient are examples of secondary groups. A society in which these relationships prevail is termed an associational society.
Man’s physical and emotional needs are best satisfied within societies, and the individual develops a sense of well-being, of belonging and fitting in. But, if they are not satisfied, the individual’s normal development is hampered, and he tends to suffer feelings of not belonging.
Because of the nature of life in technologically advanced societies, man has had to rely increasingly on secondary group relationships. In the meantime, some facets of his primary group life have been gradually disintegrating (瓦解). The extended family, which was still very much a feature of American life at the turn of the century, consisted of grandparents, unmarried aunts and uncles, and various other relatives who lived either under the same roof or in the same community, and gave mutual aid and comfort to each other (along with occasional conflict).
Today’s family, however, is reduced to the nuclear father, mother, and children, and with increased mobility access to grandparents and relatives is something impossible. The physically and emotionally supportive role which the extended family played has not been replaced by relationships within the secondary group. In a communal society, members （）.