6 By this very circumstance, the traditional local communities such as families, clans, tribes, villages, various groups and associations stemming from social contacts, experience more thorough changes every day. The industrial type of society is gradually being spread, leading some nations to economic affluence, and radically transforming ideas and social conditions established for centuries. Likewise, the cult and pursuit of city living has grown, either because of a multiplication of cities and their inhabitants, or by a transplantation of city life to rural settings. New and more efficient media of social communication are contributing to the knowledge of events; by setting off chain reactions they are giving the swiftest and widest possible circulation to styles of thought and feeling. It is also noteworthy how many men are being induced to migrate on various counts, and are thereby changing their manner of life. Thus a man's ties with his fellows are constantly being multiplied, and at the same time "socialization" brings further ties, without however always promoting appropriate personal development and truly personal relationships. This kind of evolution can be seen more clearly in those nations which already enjoy the conveniences of economic and technological progress, though it is also astir among peoples still striving for such progress and eager to secure for themselves the advantages of an industrialized and urbanized society. These peoples, especially those among them who are attached to older traditions, are simultaneously undergoing a movement toward more mature and personal exercise of liberty.
Source: Gaudium et Spes (Vatican.va)