There are also other agents for intercultural contacts and diffusion such as war, trade, media, and tourism. On the other hand, isolated areas are generally centres of stability, conservatism, and resistance of change.
Ethnographic evidences show that the most primitive tribes have been found among the most isolated communities. Discoveries and inventions have contributed much to the process of social change. This truth is increasingly realised in modern times after the introduction of modern technological know-how. Discoveries and inventions are processes of innovations that can alter society. While discoveries are the act of finding something that has always existed but that was not known earlier, inventions on the other hand are devices constructed by putting two or more things together in a new way.
The discovery of America led to the massive migrations from Europe and the creation of a new state the United States of America. The discovery of penicillin also prevented from various diseases. Again, the discovery of oil, and other minerals have also brought great social changes in the locality where it is found. In the same way, the inventions of alphabet, modern state, etc. (social inventions), automobile, telephone, etc.
(material inventions) have caused enormous social changes. Diffusion, the process of the spread of culture from group to group, has been considered as one of the main causes of social change. Diffusion takes place within societies and between societies through contact. This is why the process of diffusion becomes difficult to penetrate in a situation of isolation. Jazz, which was originated among black musicians of New Orleans diffused to other groups within the society, and then later spread to other societies as well and to different parts of the world. Social movement is certainly one of the most important factors of social change. We can understand social movement into two different forms one those movements organised to create some new social forms that are usually radical and liberal in nature; and two, those movements concerned with maintaining or recreating older social forms that are generally conservative reactionary.
However, in both these cases, social change will depend much on the success of the movements and the impact it could cause to the society. Revolutionary movement may be considered as a kind of social movement. Revolutionary movements also cause social change. The French Revolution of 1789 witnessed the rise of French democracy, rise of modern civilian army, and was a great eye-opener and model for many peoples in different parts of the world who are struggling for liberation and justice. The Russian Re- ion is also another example of revolutionary change that brought an end to monarchical government and class stratification in Russia.