The scientific study of the biological, psychological, and sociological phenomena associated with age and aging, gerontology had its origins in the study of longevity from Francis Bacon (1561-1626) onward. While Jean-Martin Charcot (1825-1893) had explored the relationship between old age and illness, the term gerontology was introduced by Elie Metchnikoff (1845-1916), who developed theories of aging based on his work in medicine and biology. Social science perspectives on aging did not emerge until later, when the economic consequences of aging were recognized. Professional associations were created to support research on aging, such as the Gerontological Society of America (1945) and the International Association of Gerontology (1948). In the 1930s the Josiah Macey Jr. Foundation in New York, under the directorship of Ludwig Kast, ran a series of conferences on aging exploring the relationship between degenerative disease and aging. The Foundation encouraged E. V Cowdry, professor of cytology at Washington University, to organize a book that would explore not only the biomedical aspects of aging but also the psychological, sociological, and environmental aspects. These activities resulted in the Club for Research on Aging, which promoted the study of aging as an aspect of public health. Major figures in the development of the social and psychological study of aging included, in the United States, Matilda White Riley (1911-2004), and in the United Kingdom, Peter Laslett (1915-2001). Riley and her colleagues developed the "aging and society paradigm" in her Aging and Society (1968-1972), which examines the interaction between a cohort flow of population and social change, and explains age as an aspect of the social structure. Laslett, the author of The World We Have Lost (1965), challenged many conventional, but dubious assumptions in demography and gerontology, such as the idea that the nuclear family is a modern development. He was a founder of the influential Cambridge Group for the History of Population and Social Structure, which pioneered the methodology of using local records in the historical study of population.
Gerontology has become an increasingly important discipline as the governments of the developed world face up to the problem of aging populations. The causes of population aging are either a rising life expectancy or declining fertility, or both. Increasing longevity raises the average age of the population; a decline in fertility increases the average age of the population by changing the balance between the young and old. In the modern world, declining fertility—in precise terms the actual number of live births per thousand women of reproductive age—is the most significant cause of population aging. In terms of the world population, in the year 2000 approximately 30 percent were under the age of fourteen years, but this is expected to fall to around 20 percent by 2050. In the developed world, the median age of the population rose from 29 in 1950 to 37.3 in 2000, and it is predicted to rise to 45.5 by 2050. For the world as a whole, the figure was 23.9 in 1950, 26.8 in 2000, and is predicted to be 37.8 for 2050. One of the fastest-aging populations is modern Japan; in 1950 there were 9.3 people under the age of 20 for every person over 65 in Japan, but by 2002 this ratio was anticipated to be 0.59 people under 20 for every person over 65 years. Worldwide, there are important regional variations. If we define an aging population as one in which at least 10 percent are over 60, then most of sub-Saharan Africa will only see the development of aging populations after 2040, but North Africa will have them before 2030. Most of the Latin American and Caribbean countries will have aging populations after 2010. Many Asian countries, such as China, Singapore, and South Korea, already do.
The United States and Northern Europe face an acute problem of rapid aging. In the United States, the proportion of the population over sixty-five years of age is expected to increase from 12.4 percent in 2000 to 19.6 percent in 2030. In absolute terms, this means an increase from 35 million over sixty-five in 2000 to 71 million in 2030. In Europe the number of people over sixty-five years will increase from 15.5 percent in 2000 to 24.3 percent in 2030.
The aging of the world population is an aspect of an ongoing demographic transition—a switch from high fertility and high mortality rates to low fertility and delayed mortality. This transition also produces an epidemiological transition—a switch from infectious diseases in childhood and acute illness, to chronic disease and degenerative illness. The principal causes of death in the developed world are cardiovascular disease, cancer, respiratory disease, and injuries.
These demographic changes have major implications for health care, the labor force, welfare, insurance, and pensions. In the United States 80 percent of people over sixty-five years have at least one chronic disease and 50 percent have two. Diabetes now affects one in five Americans. The incidence of Alzheimer’s disease in the United States doubles every five years after the age of sixty-five. The economic consequences of an aging population are various and significant. There will be major increases in health care, nursing care, and retirement home costs. As the ratio of working to retired persons increases, there will be a decline in taxation and an erosion of funds for public expenditure. There is already a significant pension crisis in the United States and the United Kingdom, where the combination of compulsory retirement and increasing life expectancy means that people do not have sufficient savings for old age. The problem is a major policy issue because labor force participation of people over sixty-five years has declined by more than 40 percent worldwide. In the United States, the growth rate of the working-age population is projected to decline from its current level of 1 percent per year to half a percent by 2030.
Life expectancy has increased significantly in the developed world. More people are surviving into old age, and once they achieve old age, they tend to live longer. Over the next half century, global life expectancy at age 60 will increase from 18.8 years in 2000-2005 to 22.2 years in 2045-2050, from 15.3 to 18.2 years at age 65, and from 7.2 to 8.8 years at age 80. In over thirty countries female life expectancy at birth already exceeds 80 years. Can life expectancy increase indefinitely?
Contemporary gerontology as a field of research is changing rapidly under the impact of advances in the biological sciences. In conventional gerontology, living a long life had meant in practical terms living a full life, according to some agreed upon set of cultural and social criteria, and achieving the average expectation of longevity according to gender and social class. More recently however, there has been considerable speculation as to whether medical science can reverse the aging process. Between the 1960s and 1980s, biologists such as Leonard Hayflick (1982) argued that normal cells had what was known as a replicative senescence, that is, normal tissues can only divide a finite number of times before entering a stage of inevitable quiescence. Cells were observed in vitro in a process of natural senescence, but eventually experiments in vivo established an important and far-reaching distinction between normal and pathological cells in terms of their cellular division. It was paradoxical that pathological cells appeared to have no such necessary limitation on replication, and therefore a process of immortalization was the defining feature of a pathological cell line. Biologists concluded that finite division at the cellular level meant that the aging of whole organisms was an inevitable process. These scientific findings supported the view, shared by most religious traditions, that human life had a predetermined limit, and that it was only through pathological developments that some cells might outsurvive the otherwise inescapable senescence of cellular life. Aging was regarded as both natural and normal.
This traditional conception of aging was eventually overthrown by the discovery that human embryonic cells were capable of continuous division in laboratory conditions, where they showed no sign of any inevitable "replicative crisis" or natural limitation. Certain non-pathological cells (or stem cells) were capable of indefinite division, and these new developments in the conceptualization of cellular life have consequently challenged existing scientific assumptions about the distinctions between the normal and the pathological. Stem-cell research is beginning to redefine the human body in terms of renewable tissue, and suggests that the limits of biological growth are not immutable or inflexible. The human body has a surplus of stem cells capable of survival beyond the death of the organism. With these developments in micro-bio-gerontology, the capacity of regenerative medicine to expand the limits of life becomes a plausible prospect of medicine, creating new economic opportunities in the application of life sciences.
The controversies that surround modern gerontology are primarily to do with population aging, resource allocation, and equality. First, can prolongevity be increased almost indefinitely? Secondly, will significant increases in life expectancy severely increase the inequality in the distribution of resources worldwide? Finally, can intergenerational justice be maintained?
In contemporary debates about the legitimacy of the life-extension project, faith-oriented beliefs and moral justifications are prominent. It is clearly the aspiration of furthering biomedical science that is the most common supporting argument in the literature. In general, scientific curiosity and potential health-enhancing discoveries are cited as justifications for life-extension research. The ethical principle of beneficence is also included, because the research, it is argued, can help to decelerate the aging process and diminish the onset of chronic illness. Such a view emerges from a conception of aging as a condition to be cured (that is, as a disease), and it assumes that health and life extension will necessarily evolve together. In these debates on life extension, Gregory Stock, director of the program on Medicine, Technology, and Society at University of California, Los Angeles (UCLA) School of Public Health, argues that we should not accept the natural life span as a fixed state of affairs, because prolonged health is a general good. Because the technological advancements in anti-aging intend to provide more youthfulness to aging people, he contends that life extension is valuable both to individuals and for societies. Similar sentiments are reflected in the posthumanist perspective, which strongly advocates the overcoming of biological limitations through technological progress. One public figure promoting life extension in England is the editor in chief of Rejuvenation Research, Aubrey de Grey at the University of Cambridge, who has vigorously supported the life-extension project.
The arguments against life extension are that, given a scarcity of resources, it will greatly contribute to the depletion of natural resources and significantly increase environmental degradation. It will increase inequality between the Southern Hemisphere and the affluent Northern Hemisphere. It will have an adverse effect on intergenerational justice by further concentrating wealth in the hands of the elderly rich. Finally, it raises important issues about the psychological and spiritual distress that the elderly but disabled cohort of survivors would confront. The prospect of "living forever" would only be tolerable if medical science could guarantee a reasonable level of mobility and well-being (such as freedom from chronic disease). There would also be the prospect of intergenerational conflict, for example in the form of ageism.
The term ageism was first employed by Robert N. Butler, then director of the American Institute of Aging, in 1968. Referring to negative stereotypes of elderly individuals that classify them as senile, dependent, or conservative in their attitudes, ageism has become an important political issue. Against the background of the rapid aging of populations, new ageism refers to intergenerational conflicts of interests where the elderly are criticized for being parasitic on society, that is for being "takers" rather than "givers." Some aspects of ageism can be overcome by making more accurate information about aging available, especially to young people. Another change would be to remove a fixed or compulsory retirement age, thereby allowing fit and able elderly to continue in employment. These strategies will come up against the fact that, given high unemployment, housing shortages, and other scarcities, there will be an inevitable conflict of interests between age groups. There are few convincing social policies to resolve the pension crisis, the impact on health care, and the erosion of the tax base that are outcomes of population aging.
This pessimistic conclusion can be challenged by arguing that technological improvements will continue to increase the productivity of those who remain at work, and that flexible retirement regulations will allow people to remain employed on a voluntary basis past sixty-five. We cannot assume that the values and attitudes of old people in the past will be characteristic of future generations. The postwar Baby Boomers who are now close to retirement are socially and culturally very different from their parents and grandparents. The social character of aging and the cultures of the elderly will continue to change and evolve over time, thereby making pessimistic extrapolations from past generations unreliable, and often prejudicial.
