The history of migration dates back as far as the African inhabitants moved to Eurasia 40,000 years ago. Americas were inhabited a little later, about 20,000 years ago, but still, the US is a bright example of human migration and settlement. Sociologists underline that relationships within the tribal groups which migrated were more intimate as people knew each other well. As the communities developed from the traditional to modern societies, most people experienced migration during this transition. Migrants were mentioned in the Karl Marx’s works as he commented on peasants who worked in agriculture turning into the wage-laborers. Marx wrote that these people were definitely the migrants from rural areas.
Migration studies were strongly advanced by the research of geographers and economists. Apparently, one of the first scholarly articles on migration was written by geographer Ravenstein who concentrated upon the migration laws in England. Another well-known geographer Wilbur Zelinsky proposed a theory of mobility transition which enlightened five stages of human mobility according to their development. Soon, his colleagues determined migration as an age and class dependent social behavior. The age pattern of migration was proven to be universal, and only rates of migration usually differ from one country to another.
The contribution of the economists to the migration studies was made in form of the micro-economic theory of human migration developed in 1969. According to this theory, humans move to the places where they can be the most productive. A decade later, the neoclassical macro-economic theory pointed out the importance of wage differentiation which boost migration between the regions. According to the latest research, the wage gap is an important stimulus for migration, but it does not exceed social stability and safety issues.