Till recently, population studies were generally regarded as a branch of sociology, or economics, or even geography. Most of the variables and the theories which explain demographic Phenomena originate in the social sciences.
The theory of demographic transition is based on an understanding of such other disciplines as economics, sociology, political science, psychology, anthropology and geography. Many of the fertility theories are based on biology, sociology and economics.
The changes in the birth rate cannot be explained as independent phenomena. Rather, their Plan nations have to be sought in the changing economic, social, rural, psychological and political situations in which they occur. “Nearly, the levels and trends in mortality are related to socio factors.
In recent times, another dimension has been added study of population: demographic questions, such as those related to fertility regulation, are examined with reference to humanistic issues such as human right and the status of women.
Though it is possible to speak broadly of the inter-relationship between population studies and the social and the behavioural sciences considered together, it would be useful to consider each of the social and behavioural sciences separately to understand their inter-relationships.
(a) Population Studies and Sociology:
Davis has referred to the following areas of study which require a combination of demographic and sociological skills: “(1) Fertility in connection with attitudes and social institutions; (2) Population changes in relation to social and economic change; (3) The labour force with respect to population structure and social organisation; and (4) The family with regard to demographic behaviour.”
International and internal migration is two other areas of study mentioned by Davis, where knowledge of sociology and demography need to be combined.
Even in the study of mortality, age and sex differentials, though biologically determined, may have sociological bases, and, therefore, need to be recognised as such.
Broom Selznick treat population as one of the nine principal “elements of sociological analysis” for the discussion of six special topics, that is, family, city, minorities, industrial sociology, political sociology and criminal behaviour.
It, therefore, appears that along with social organisation, culture, socialisation, primary groups, social stratification, associations, collective behaviour and ecology, populations is an important element in sociological analysis.
(b) Population Studies, Psychology and Social Psychology:
Several questions connected with family planning and fertility regulation can be answered only when the reproductive behaviour of individuals is understood in the context of the social standards cultural norms which influence and govern such behaviour.
For instance some questions, which are often asked, are: “What is the family size norm in a community? How is it determined? Is it possible to modify this norm by stimulating planned change?”
Even in the field of mortality, utilisation patterns of health care services can be understood only when individual behaviour is explored and the relevant social norms are studied. Movements from rural to urban areas can also be studied only by understanding the motivation behind such migrations.
(c) Population Studies and Economics:
The study of population is an important area of investigation in the field of economics, specially since problems of economic development and development planning have come to the forefront in most developing countries.
In order to gain a better understanding of the relationship between population trends and economic growth the following topics have emerged over the years and continue to occupy an important place, both in economics and population studies: population and development; manpower studies; the economics of fertility; and comprehensive economic-demographic models.
It has been even claimed that the number and quality of the population that can exist on the earth in the future will depend on, among other factors, economic opportunities and economic organisation.
“Population growth, size and distribution cannot be discussed rationally except in the context of economic growth or change.”
Population Studies and Geography: Students of population studies are usually interested in the geographical distribution of the population and its movements between rural and urban areas.
Those geographers, who are interested in geography not only as an academic discipline but as a geographic point of view to understand the world, point out that it is useful to know how the various issues facing the world for instance, rapid population growth, urbanisation, race relations, etc. assume different forms in different regions or contents.