It is the most basic aspect. We all are a part of the society and it is this society that does the conditioning of migration socially. The society as whole demands and strives for change for its upliftment. This common purpose makes the society well-knit and it evolves as a unified single entity. They follow their own principles and beliefs. According to the sociological theories of Emile Durkheim, society encapsulates social facts and these facts hold the society together. There exists a collective conscious.
Durkheim argues that they base their lifestyle on such strong social facts and collective conscious that they function as independent individuals but revolving and evolving around the established set of beliefs.
When even a single person or say a small population decides to leave their place of origin, it means they will step outside their cultural- economic society. That they no longer will be forced to follow those principles and it becomes their choice if they wish to continue living by them no matter where they live in.
Then on they will adopt the way of living of their host country which just likes ones native country will have a unified society. Their lifestyle, values, and culture will differ to great extent sometimes and in order to become a part of it one has to adapt their practices and adapt to the conditions. Psychology has two terms which explain this: adaptability and flexibility. In order to become adaptable, one has to learn to face and manage stress well. It is related to a scientific term stimulus which means how sensitive does one become to its environment. And the success of a person all depends on how adaptable he becomes because then the pressure of being an alien goes off and it increases the efficiency of the person. On the other hand to be flexible means to be adjustable. This also depends on how well is one received.
Approaches to sociocultural evolutions have been observed since 19th and 20th centuries while the evolution in practice has been observed right from the primitive times, as primitive as the stone age or bronze age or the iron age. Change has been constant and different societies have gone through different stages of headway. Talking of spatial and social mobility, at one time a class of people might try to fit into its sociocultural, socioeconomic and socio-political environment but at the same time, it might also aspire to upgrade and optimize its indulgence through mobility.