Kingsley Davis

Kingsley Davis (August 20, 1908 – February 27, 1997) was an esteemed sociologist and demographer, contributing to our understanding of human societies worldwide. In addition to his international work, he also made detailed studies of American society, particularly the changes in family structure due to increasing rates of divorce and the consequent weakening of the institution of marriage. Additionally, he studied the effects of extreme isolation on human growth and development, showing that environmental stimulation, particularly from another human being, is essential to psychological development. A Hoover Institution Senior Research Fellow, Davis was the first sociologist to be elected into the United States National Academy of Sciences and is credited with the coining of the terms "population explosion" and "zero population growth." His prediction of world population growth was remarkably accurate, and his recognition of the need to balance population with the ability of the environment to sustain that population was a significant insight.


Davis developed a pessimistic outlook on the future of industrialized societies, based on his own research, and theories. However, if other factors, such as the spiritual advancement of humankind leading to our successful stewardship of the environment, are taken into account, a more optimistic view is tenable.


Kingsley Davis, grand-nephew to the confederate President Jefferson Davis, was born in 1908 in Tuxedo, Texas. After graduating from the University of Texas in 1930, with a B.A. in English, Davis continued his education earning a M.A in philosophy from the university in 1932, and a M.A. in sociology from Harvard University in 1933. Three years later, while an assistant sociology professor at Smith College, Davis earned a Ph.D. from Harvard University.

Shortly after, Davis began an esteemed teaching career accepting positions at Clark University, Pennsylvania State University and serving as an associate professor of anthropology and sociology at Princeton University. While there, Davis completed and published his first work, Human Society (1949), and was later invited to direct the Bureau of Applied Social Research at Columbia University.

Davis’ mastery of demography would later lead him to the University of California at Berkeley, where he remained for more than twenty years as a professor of sociology and comparative studies. In 1977, Davis accepted his final professorship within the sociology department of the University of Southern California.

In 1997, Davis would eventually succumb to Parkinson’s disease in his home in Stanford, California. He was the father of four.


Throughout his career, Davis led a number of Carnegie sponsored teams throughout areas of Africa, India, Europe, and Latin America to gather research and direct international studies of societies. It was while on these expeditions that Davis developed his social theories for a general science of human society. During this time, Davis published a range of studies including The Population of India (1951) and the two-volume World Urbanization (1972).

Davis’ mastery of international demographics and sociological phenomena inspired him to produce a number of publications encompassing global population problems, international migration, world urbanization, and population policies. His international knowledge of world population growth and resources also lead him to promote the global use of fertility control.

As well as studying demographics worldwide, Davis also focused his attention on specific sociological trends within the United States. He was disturbed to note that marriage, which he viewed as an essential societal institution, was becoming weakened by changing attitudes towards divorce, leading to changes in family structure and kinship patterns.

Davis is well known for his coinage of the terms zero population growth and population explosion.

Zero Population Growth

Zero Population Growth (ZPG), a concept defined by Davis, is a condition of demographic balance where the population in a specified group neither grows nor declines. Zero population growth is achieved when the birth rate of a population equals the death rate of the population. This state is often a goal of demographic planners and environmentalists who believe that reducing population growth is essential for the health of the ecosphere. Achieving ZPG is difficult, however, as a country's population growth is determined by a variety of causes, including economic factors.

Population Explosion

According to Davis, a "population explosion" refers to an increase in the population of some plant, insect, or animal. In many circumstances, conditions of population explosion lead to the inability of the environment to properly sustain that population. Without the necessary environmental conditions, groups experiencing population explosions can face decimation. When applied to human society, such an eventuality naturally leads to serious concern. Davis' promotion of fertility control policies was his response to this possibility.

Extreme Isolation

Davis also published a series of studies regarding severe isolation, including a study of the physical and mental progression of a six-year old girl, Anna. Anna was discovered by a social worker after suffering extreme social and sensory deprivation since birth. After significant rehabilitation, Anna made progress in early stages of walking and speech, reaching the level of a two and a half to three year-old child, when she died at the age of ten. He also studied another girl, Isabella, who was raised for six years by her deaf mother in a dark room. She, however, fared better than Anna when rescued from this isolated environment, passing sixth grade in school by the age of fourteen at the time Davis concluded his observations. Davis published two studies that detailed his studies of extreme isolation: The Extreme Social Isolation of a Child (1960), and its follow-up, A Final Note on a Case of Extreme Isolation (1993).


In 1981, Davis was honored with a Hoover Research Fellowship and was appointed the institution’s senior research fellow. In 1982, Davis received the Career of Distinguished scholarship Award from the American Sociological Association. He was later named president of both the Population Association of American and the American Sociological Association. Davis served as the United States representative on the United Nation’s Population Committee, and was a member of NASA’s Advisory Council. In addition to scholarly journals, Davis’ work appeared in the popular press, including New York Times Magazine.

Davis is credited with the development of a complex social theory defining the general science that encompasses human societies. He maintained a lifelong interest in the comparative studies of population structure and change. His studies of family structures in America and the institution of marriage led to his belief that factors of contraception, divorce, and gender equality were leading to the weakening of matrimonial bonds.

Davis’ studies of industrial and non-industrial societies also led to his 1957 prediction that the world’s population would reach six billion in the year 2000. This proved remarkably accurate, as world population reached six billion in October of 1999.


  • Davis, Kingsley. "Extreme Social Isolation of a Child" in American Journal of Sociology. 1940.
  • Davis, Kingsley. Human Society. MacMillan, 1949.
  • Davis, Kingsley. The Population of India and Pakistan. Princeton University Press, 1951.
  • Davis, Kingsley. Cities: Their Origin, Growth and Human Impact. W.H. Freeman, 1973.
  • Davis, Kingsley. World Urbanization: 1950-1970. Berkeley Institute of International Studies, 1972.
  • Davis, Kingsley. Contemporary Marriage: Comparative Perspectives on a Changing Institution. Russell Sage Foundation, 1986. ISBN 0871542218
  • Davis, Kingsley. Final Note on a Case of Extreme Isolation. Irvington Publishers, 1993. ISBN 0829037896
  • Davis, Kingsley. A Structural Analysis of Kinship: Prolegomena to the Sociology of Kinship. Arno, 1980. ISBN 0405129629


  • Horaney, Michelle. "Kingsley Davis Obituary" in Stanford University News Service. Stanford, CA, 1997.


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