THEORY OF POPULATION GROWTH:Theory of Demographic Transition

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Introduction to Sociology SOC101

Lesson 36

THEORY OF POPULATION GROWTH

In pre-modern societies, birth rates were very high by the standards of industrialized world today.

Nonetheless, population growth quite was low until the 18th century because there was a rough overall

balance between births and deaths. The general trend of the numbers was upwards, and there were

sometimes periods of more marked population increase, but these were followed by increase in death rates.

During the period of the rise industrialism, many looked forward to a new age in which scarcity would be a

phenomenon of the past. The development of modern industry, it was widely supposed, would create a new

era of abundance in which standards of living would rise. These ideas were criticized by Thomas Robert

Malthus (1766-1834), a clergyman and an economist.

Malthusian Theory of Population

In 1798 Malthus published an Essay on the Principle of Population. By analyzing the then prevailing situation in

different countries Malthus initiated a debate about the connection between population and food resources

that continues to this day. His premise was that: (1) food was necessary for the continuation of life, and (2)

procreation was also necessary for the continuation of life. Necessity of food for human survival is to

continue, similarly the passions between the sexes are to continue, and both are natural necessities of life.

But the two necessary factors of human life grow at different rate. Whereas population size increases

geometrically (2, 4, 8, 16, 32, 64), the food supply increases arithmetically (1, 2, 3, 4, 5, 6,). Population size,

therefore, always pushes against the limits of food supply needed to support the population. There is a limit

to increase the food supply by bringing more land under cultivation but there is limit to that. With the

existing rate of growth, the population was expected to double every 25 years.

For such a high growth rate of population, human beings should adopt such measures to check the growth

of population. In his opinion the population checks were:

Preventive checks, and

Positive checks.

Among the preventive checks, Malthus recommended (1) to follow celibacy (2) to marry late, (3) abstinence

from entering into sexual unions resulting in procreation. If human beings don't adopt the "preventive

checks", "positive checks" come into operation in the form of famine, epidemics, war, and other natural

calamities, and a lot of population is wiped out. For the remaining population food supply may be

sufficient, though it may be a temporary relief.

There has been lot of criticism of Malthusian theory of population by arguing that:

Malthus did not visualize the power of science and technology with the help of which the food

supply could be revolutionized. Even one country like Canada could produce so much of

wheat that could be sufficient for the whole of the world. But will Canada supply wheat free?

Not at all. Even if it is free some countries may not even have the ability to bear the

transportation costs.

Malthus did not advocate the use of contraceptives as a means of preventive measure, though

these were available during his times. Being a clergyman perhaps he did not consider the

advocacy of the use of contraceptives as appropriate.

Malthus presented a too pessimistic picture of the growth of population. Population of many

technologically advanced countries did not follow his predictions.

Nevertheless, the essay on population growth by Malthus generated lot of discussion on the topic, and

Malthus may rightly be considered as the father of population studies. The more guarded outlook is that we

no longer could use technology as an excuse to ignore Malthus.

Theory of Demographic Transition

Demographic transition theory links birth rates and death rates to a society's level of industrialization 

the process by which a society's economy shifts from a predominantly agricultural and handicraft base to a

predominantly industrial and large scale manufacturing base. There are four stages in the demographic

transition as seen in the figure.

Introduction to Sociology SOC101

During the pre-industrial stage, high birth rates are balanced by high death rates, and population size

remains fairly stable. Today the least industrialized nations of the world are in this demographic stage.

During stage 2, the stage of increasing industrialization, the death rate falls primarily because of the

improved sanitation, hygiene, and medical conditions. The birth rate, however, remains high because of the

continued influence of traditional values favoring large families. Having several children ensures survival of

at least some of them when infant mortality is high. During this stage the imbalance between the falling

death rate and the high birth rate results in high population growth. Pakistan like many other developing

nations is in this stage of transition.

At the third stage the traditional values give way to modern values favoring contraception and family

planning. Birth rates decline as a result of later ages at marriage, urbanization, industrialization, rising

aspirations, and other factors. The mortality rates eventually stabilize at low level and birth rates follow.

The shift from high to low mortality and fertility is known as the "demographic transition". This shift

occurred throughout Europe, North America, and a number of other areas in the 19th and early 20th

centuries, and started in many developing countries in the middle of 20th century. Although the pace and

paths of decline varied tremendously among countries, the demographic transition emerged as the dominant

model of demographic change.

At the fourth stage the birth rates fall to about the same level as mortality rates. With births and deaths at

similar low levels, the equilibrium of slow population growth is regained.

The pace of change in a country varies depending on its culture, level of economic development, and other

factors. As countries pass through the various stages of the transition, population growth from natural

increase (birth rate - death rate) accelerates or decelerates depending upon the gap between birth rate and

the death rate. Many developing countries are in an intermediate stage, in which mortality and fertility are

falling at varying rates but are still high relative to the levels of Europe and other more developed areas.

Many low-fertility countries have entered what some describe as a "second demographic transition" in

which fertility falls below the two-child replacement level as forces of contemporary life interfere with

childbearing. This transition has been linked with greater educational and job opportunities for women, the

availability of effective contraception, a shift away from formal marriage, the acceptance of childbearing

outside marriage, and the rise of individualism and materialism.

Experts disagree about whether all countries will follow the transition experienced in Europe and about

whether there are additional stages of transition that we have not identified long-term population decline,

for example. But the demographic transition theory provides a useful framework for assessing demographic

trends and projecting future population size.

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