 Dear students, in this module, we are going to talk about the different theories of migration that explain this important aspect of human life, that why do people tend to migrate from one place to another place. Migration is a very complex phenomenon and it is determined by the set of economic, political, social as well as environmental factors. So it is also determined by the perception and behavior of the individuals concerned. First of all, let's talk about the Ravenstein's laws of migration. Interestingly, there is an inverse relationship between the migration and distance. For example, the longer the distance, the minimum are the chances to migrate and majority of migrants move to the shorter distances only. The migration proceeds step by step. It is not usually being performed just in a one go and inhabitants of rural areas have the greater chances of mobility for migration because as you know, in urban areas, we have a lot of amenities and facilities of life available. So these can be a source of attraction for the people from rural areas. As soon as their economic situation gets better, they tend to migrate to the urban areas. And migration is highly age-selective. For example, younger people are more likely to migrate as compared to the older people. And migration occurs mainly due to the economic reasons. However, in the modern days, we do find that migration due to the education purposes is also pretty much prevalent among the youth. And then we have the gravity model. It means that the migration between any two interacting centers is the function of their population size. Underpopulation determines the immigration. If a certain area possesses the high population density, people would tend to migrate. Usually it occurs in the urban areas. Underpopulation determines the immigration. So this model was proposed by the exponents of social physics in the 19th century. Usually the gravity model has been considered applicable until the 20th century, but now since new innovations and new amenities of life are available in the urban area. So people usually tend to stick to these urban areas because they find attraction in these amenities of life. And they do not usually find the alternative sources which could compel them to go to the other areas. The Stufas theory of mobility suggests that there is no necessary relationship between mobility and distance. So he agrees with the theory that the distance and mobility are inversely relatable. Availability of opportunities determines the migration. Actually, where you find more opportunities, you tend to migrate. And economic factors and ideas of their fulfillment are very forceful motivation behind the migration. And also we have the Lee's theory of migration that says that migration is the natural result of interplay between pull and push factors. That's a very prevalent theory in the modern migration literature. And pull factors are the factors that attract a migrant to come to a certain destination such as the economic opportunities, health opportunities, business opportunities or maybe education opportunities. And then we have the push factors that are the factors that compel an individual to migrate to the new destination that might be a war or a natural catastrophe or a calamity or maybe the absence of certain life facilities. For example, if you are finding it difficult to find water or food in a certain area, so you tend to migrate to another area. The volume of migration varies with the degree of diversity in the area of destination that where there are more facilities, people tend to go over there. The volume of migration varies with the fluctuation of economy as well. So it is not always fixed that people would always be migrating to a certain area. It would depend on the circumstances as well as the situation of facilities available over there. So more the facilities are available and more people tend to migrate to that area. And migration also tends to take place within the well-defined streams. For example, where there is a lot of trend, as we have seen that during the 70s and 80s, there was a very current trend of that time to migrate to Europe or European countries or maybe in the Middle Eastern countries to go to search for the opportunities of livelihood. And migrants responding to the pull factors at the destination tend to be positively selected. And also we have the neoclassical theory. It assumes that the labor markets and economies move towards a state of equilibrium. It means that it considers the migrants as the rational actors. They are not just acting based on weather pusher pull factors. So they rationally decide about the possibilities of migration by calculating their chances of acquiring the benefits of migration on a certain place. And migrants move from societies where labor is abundant and wage is low. So as you have seen that there is a greater trend in the modern world to migrate to the developed countries as compared to the developing and underdeveloped countries because there are more opportunities, more economic opportunities available. So the decision to migrate are taken usually at an individual level as compared to what is reflected in the other theories. And also we have the migration systems and network theory that focuses on the nexus between people at the origin and at the destination. For example, if a person has gone to Europe, he is more likely to call his other relatives to Europe as well. So this creates a nexus of communities. And migratory movements are often connected to prior longstanding links between the sending and receiving territories. These connections give birth to the migration system and people move where they can rely on someone they already know. For example, people do migrate to other countries if they are usually being called by the people who are already there or maybe they are becoming the spouses to go over there. And finally, we have the word system theory that emphasizes on the migration from the peripheral to core countries. By peripheral countries, it means that those countries who are economically dependent or who are economically less stable as compared to the core countries which are economically developed and more modernized countries. So migrants move from periphery to core while the goals, capital and machinery flow from core to peripheral countries. So these countries are considered usually the economic hubs where most of the innovation is being produced where most of the innovative technology is available. So they are usually attracting more and more migrants because of having a lot more economic opportunities. And migration occurs due to the shortage of labor in those developed countries as well.