In this article, You will read Theories of Migration – for UPSC (Population and Settlement Geography – Geography Optional).
Migration, fertility, and mortality are the basic fundamental elements determining the population growth and demographic structure of a country.
The most striking feature of migration is that it can increase or decrease the population size and change its structure drastically at a given point in time. It also has a drastic impact on the fertility and mortality of a place. For example, when the male population migrates, the females are left alone which will bring down the fertility rates.
The Multilingual Demographic Dictionary in collaboration with the International Union for the Scientific Study of Population (IUSSP) describes migration as a form of spatial mobility, involving a change in the usual place of residence and that implies a movement beyond an administrative boundary.
As per the UN, migration is a form of spatial mobility of population between one geographical unit and another involving a permanent or semi-permanent change in residence.
- However, a certain type of movements are conventionally not qualified under migration like:
- Circulation (transferable jobs)
- Transhumance (seasonal movements of up and down the valley by tribes in mountain areas like Gaddis (Sheep bearers) in Himanchal Pradesh and Bakkarwals (cattle bearers) in Jammu and Kashmir)
- Refugees are also not considered as migrants. They are rather a population of concern, very vulnerable to human trafficking and labour abuse. They are not given the right to citizenship.
Migration is a very complex phenomenon. Apart from a set of social, economic, political, and environmental factors, migration of population in any region is determined, to large extent, by the perception and behavior of individuals concerned. Therefore, there is no comprehensive theory of migration, although attempts have been made, from time to time, to integrate migration into economic and social theory, spatial analysis, and behavioural theory.
Theories of Migration
Migration can be broadly divided on the basis of two analytical models – the macro and micro analytical models.
Some of the prominent models involved in the Macro analysis include the Ravenstein Model (Gravity Model), Zipf Model (Model of Least Effort), and Stouffer Model (Intervening Opportunity Model). The Major Micro Analytical model is Lee’s Model.
Some of these models are an extension and up-gradation of basic models such as that of Ravenstein, Zipf, Lee, Todaro, etc.
Ravenstien’s law on migration
- Ravenstein studied patterns of migration in the UK in the 1880s using the Census birth-place data. Ravenstien took into the analysis of international migration trends across the North Atlantic (based on his studies in the UK) between 1885 to 1889.
- In his model, Ravenstein talked about ‘migration phenomena’ which revolves around the streams of migration. According to him, migration is a continuous process resulting in the more balanced redistribution of the population. However, for each migration stream, there is a counter stream. The model is actually based on a series of predictive statements.
- The basic example of the streams of migration is when an individual migrates from his/her place of origin to a specific destination; he/she forms a link between the two places and then the other people from the same place start to come to the same destination, leading to social capillary movement.
- Based on these analyses he outlined some theories on migration including:
- There should be a reason to migrate
- The majority of migrants travel short distances (distance decay effect). For example migrants from Mexico migrate to South USA, not to Canada.
- Most migrants move relatively short distances creating an inverse relationship between the number of migrants and distances traveled.
- People who move long distances are largely unaware of opportunities available at the destinations and tend to move to larger urban centers.
- The main cause of migration is economic due to which most of the migrants are directed towards commercial centers (especially long-distance migrants)
- Adults migrate more than families, especially male adults.
- Men are more likely to emigrate than women. Most migrants are adults.
- Females migrate short distance (e.g. marriage) whereas male venture beyond ( for commercial reasons)
- According to Ravenstein, women are more likely to migrate within their country for a relatively shorter distance than men.
- Big towns grow more due to in-migration than due to natural factors.
- With technological advancement magnitude of migration increases.
- Every migratory current has a weak and opposite counter current. Both currents display similar characteristics.
- People in urban areas migrate less than that of people in the rural area (most migrate from agriculture to industrial areas)
- Most migrants are in the 20 to 35 years of age group.
- Migration occurs in stages, leading to stepwise migration. Ravenstein Migration occurs in stages, leading to stepwise migration.
- Migration increases along with the development of industry, commerce, and transport.
- Every settlement has an attractive field that is directly proportional to its size and inversely proportional to the square of the distance (gravity law)
- Urban housing is almost inadequate to accommodate the influx of migrants, so the obvious consequence of migration is the growth of slums and shantytowns (unauthorized towns with a lack of proper infrastructure).
Evert Lee model on migration
- This model involves the consolidation of fragmented theories outlined by Ravenstien.
- Lee emphasized that migratory decisions are regulated by 4 sets of factors:
- Factors operational at the place of origin (push factors)
- Factors operational at the place of destination (pull factors)
- Factors operating as intervening obstacles
- Factors specific to individuals
- For migratory decision to take place the pull factors are required to be strong enough to suppress place belongingness acting in place of origin satisfying the individual requirement and overcoming intervening obstacles (lack of connectivity, large distance, etc.)
- Intervening obstacles may prevent migration from taking place or may reduce the number of people moving away. The intervening obstacles/ factors could be negative, positive as well as neutral in nature such as religion, services, misinformation, political differences, government policies, immediate job opportunity, travel cost, language, etc.
- Lee found that in the place of origin as well as the destination, intervening obstacles, life cycle, social as well as personal characteristics of individuals are the main factors leading to migration or spatial mobility. His hypothesis was that migration depends upon volume and stream of migration as well as characteristics of migrants.
- Pull factors for migration:
- People with advanced technology has historically invaded and conquered new areas e.g. Romans in the ancient period, Europeans in the modern period.
- Less advanced people got attracted to developed societies which led to their migration. For example migration of Asians to the USA.
- Economic factors:
- It is the primary factor leading to migration. For example the migration of plantation labours from Africa to the Virgin land in America.
- The unemployed agricultural labours migrated to the neighbouring fertile tracts.
- It also includes the settlement of Europeans in prairies.
- Pressure on land resource and lack of employment opportunities leads to migration especially from rural to urban areas. For example migration from South Asia to the USA and West Asia, migration of labourers to Punjab.
- Push factors for migration:
- Overpopulation influences the standard of people living in an area. Therefore, people tend to migrate to places where there is better job opportunities and a high standard of living.
- For example migration of people from East to West i.e. from highly populated developing countries of East to developed countries of West.
- Socio religion causes: it includes the migration due to
- Persecution of minorities (Jews, Muslims, Hindus etc.) in the source area.
- Lack of health, education and other basic facilities in the source area.
- Other social factors such as caste discrimination, taboos, etc.
- Political causes: It includes-
- Factors like the partition of country (Indo-Pak)
- War (Arab-Israel led to the migration of Palestinians)
- Expulsion of minorities.
- Demographic factors and population pressure:
- Age is an important demographic factor controlling the degree of desire to move.
- Migration from densely populated regions like Kerala, Bihar, West Bengal
- Movement of Europeans from Europe across the Atlantic.
- Diffusion of information:
- Availability of information through education, cultural contacts, etc has increased the chances of migration.
- For example migration of Sikhs to West America, the UK, even to Bolivia, Honduras etc.
- General rise in the level of aspiration
- As technology advances and the standard of living rises in some areas, people in less advanced areas aspire to such living.
- Both educated and uneducated are tempted in spite of the fact that they are better off than their father.
- Example- doctors, engineer move to the USA, migration of labourers to West Asia.
- Wars have been a major cause of migration.
- For example migration during the Second Word War, an exodus of Tamils from Sri Lanka.
- Government policies:
- Governments across the world make policies that are either favourable or against migration.
- For example US immigration policies, migration policies of USSR, Siberia, Indonesia.
Zipf’s inverse distance law
- Zipf’s model of migration states that the volume of migration decreases with distance from the origin, resulting from the obstacle between the place of origin and that of the new destination (Zipf, 1946). Zipf defined these obstacles as a simple inverse function of distance.
- Obstacles of West African migration are difficulties and the red tapes involved in migrating to Europe and the United States.
- As a result of these obstacles, potential West African immigrants are left with South Africa as the best available option.
- Unlike the Gravity model, Zipf’s model failed to map the direction of the migration flow, and, it is however doubtful if the number of West African immigrants heading to South Africa decreases in any significant way before their arrival in South Africa.
Stouffer’s Law of Intervening Distances
- As per Stouffer, migration is not related to the distance and population size of the city as the gravity model claimed but it is depended on the number of opportunities available in that location.
- Stouffer in his ‘Intervening Opportunity Model’ argued that distance is a surrogate for the effect of intervening opportunities. The migration stream from the place of origin to the place of destination is assumed to be inversely related to the number of intervening opportunities.
- In other words, the number of persons moving for a given distance is directly proportional to the number of opportunities at the destination and inversely proportional to the number of intervening opportunities.
- So, the nature of a place is more important than distance. Stouffer further revised his own model as the ‘Competing Migrant Model’.
- According to Stouffer, the number of migrants moving from one point (A) to another (C) is directly related to the opportunities available at point (C) but inversely proportional to the number of intervening opportunities between point (A) and point (C).
- A large number of Indian migrants to West Asia/Europe/USA as compared to central Asia/China/Russia because of the number of opportunities available in West Asia/Europe/USA is more as compared to central Asia/China/Russia.
- Students from India will not go abroad to study if they get admissions to IIT/AIIMS.
- The NCR planning and development of satellite towns around Delhi is to decongest Delhi, is based on Stouffer’s principle.
- Intervening opportunities are those factors persuading a migrant to settle at a place between the place they left and the place they intended to go. It occurs when a person likes the facilities of an area and decided to reside there permanently, although they did not plan it to be their final destination.
- Intervening opportunities offer opportunities, such as jobs, land, education, and political freedom complementary to the ones originally required at the planned destination.
- Intervening obstacles such as language barriers, international boundaries, or anxieties affect the migrants negatively, while an intervening opportunity affects people positively.
The Gravity Model is based on Newton’s Law of Gravitation and was expanded by William J. Reilly in 1931. As per the model, the number of people moving between places ‘A’ and ‘B’ is equal to the population of ‘A’ multiplied by the population of ‘B’ divided by the square of the distance between them.
In other words, the movement of persons between two urban centers would be proportional to the product of their population and inversely proportional to the square of the distances between them. The potential number of migrants will be bigger where the population of the place of departure and arrival are large. This model was further modified to include social factors.
This theory states that larger towns are more attractive to migrants than smaller towns (Bogue, 1969). Though it mostly applies for internal migration, it can also be applied in international migration notably, more developed countries will be more attractive to immigrants than less developed countries. Hence, it would explain why in Africa most West Africans are attracted to South Africa, which is relatively more developed than elsewhere in Africa.
But, it does not account for what makes South Africa more attractive, and what makes immigrants’ country of origin less attractive. The model also fails to predict future migration patterns, and the trajectories involved in migration.
However, the model correctly predicts the direction of the migration flow, from less developed to more developed countries. The latter having generally more and larger towns.
Zelinsky’s Mobility Transition Model
- In the year 1971, Zelinsky attempted integration of migration in the demographic transition model identifying the influence of the growth of population, cultural-economic advancements on migratory decisions, he analyzed the transition in migratory movements at 4 variable scales:
- International and regional migration
- According to Zelinsky’s model, international and regional migration represents the highest level after expanding early stage.
- This is primarily due to the increase in population as well as the capacity of people to move from one location to other.
- The difference in volume is primarily attributed to involved distance in international and intra-national migrations.
- In the international category, the decline in migration in spite of the growing population is correlated to in-migration norms that become more rigid with the advancement of culture and modernization.
- In the case of regional migration, the decline in migration is registered due to the positive outcomes of the regional development programs which minimize both real and perceptional differences between regional and ‘rural-urban scales’.
- The continuation of dominating the pace of migration for a longer time period is due to the delayed implementation of rural development.
- Level of urban to urban migration depicted as a special case that involves continuous rising trends as per functional capacity differences between different urban places.
- It is this difference that makes town dwellers always attracted to city and city dwellers to megacity.
- The significance of the Mobility Transition Model relates to fact that this model helps in interpreting an entire range of migratory movements in the global and international levels that have resulted in the genesis of dominating cultural or economic identity of the population.