Migration and Population Change. Push and Pull Factors. Search Space and Place Utility

So far, our discussion of population has focused on birth rates, death rates, and population change. We now turn our attention to the process of migration—a very important component of population changes throughout the world.

Most people migrate from one place to another several times over the course of their lifetimes. Why do people move? Some move as a result of political or religious persecution. Others move in order to improve their economic or social status. Still others move in association with changes in the life cycle—marriage, childbirth, or retirement.

Push and Pull Factors. In general, the many reasons that individuals move can be grouped into two broad categories — push factors and pull factors. The migration process consists of two discrete decisions: the decision to leave one's current residence, and the choice of a new residence. Push factors are those that encourage people to move away from their current homes. Racial discrimination, poverty, unemployment, religious persecution, natural disasters, wars, family problems, and political events are important push factors.

Pull factors are those that encourage the selection of specific destinations. Examples include employment possibilities, climate, recreational opportunities, and the presence of close friends and relatives. Many recent college graduates flock to cities where job opportunities are plentiful. Of course, not all pull factors are directly related to economic opportunity. Many people choose destinations because of climate, recreational opportunities, or other amenities. Victims of political or religious persecution choose destinations where their values are accepted. Retirees often evaluate migration destinations on the basis of crime rates, cost of living, and the availability of medical care.

Search Space and Place Utility. In general, a person deciding to migrate chooses a destination after evaluating potential residences on the basis of how well each suits his or her individual needs. First, the migrant identifies a search space — that set of places to be considered and evaluated. Having identified the search space, the migrant compares the places within it. This comparison involves the evaluation of place utility. The migrant moves to the place with the highest place utility.

Suppose that you are offered a well-paying job in your major field after graduation. The company employing you has offices in several different states and foreign countries. Which office would you choose to work in? In order to make this decision, you might consider such criteria as cost of living, opportunity for professional advancement, climate, recreational opportunities, and social possibilities. In this example, the search space consists of the places in which the company's offices are located, and the criteria we have mentioned form the basis of place utility. You would use these criteria to compare the office locations. That location whose characteristics were closest to your ideal would have the highest place utility, and that would be the one you would choose.

Of course, examining migration from the perspective of search space and place utility presumes that migration is a voluntary decision process. In fact, many people have no choice about whether to move or where to move. For example, the spread of European culture around the world resulted in the large-scale resettlement of many indigenous populations. Native Americans, the Australian aborigines, and the Maoris of New Zealand were forced to move to reservations.

In the Americas. European colonists arranged for the importation of slaves to provide a supply of labor in their newly established colonies. Africa soon became a source of slave labor. Over a period of several centuries, at least 10 million Africans were captured and sold into slavery throughout North and South America. Descendants of Afro-American slaves remain an important component of the population of the United States, the Caribbean islands, and many countries in Central and South America.