GERONTOLOGY

The quest for explanations for why we age is nearly as old as the written record, going back to long before Ponce de Leon's fabled search for the "fountain of youth" in the early 1500s. It was not until the beginning of the twentieth century, however, that the term gerontology emerged. Writing in 1903, the zoologist Élie Metchnikoff noted "it is extremely probable that the scientific study of old age and of death, two branches of science that may be called gerontology and thanatology, will bring about great modifications in the course of the last period of life" (pp. 297–298). Derived from the Greek words geront ("old man") and logia ("the study of"), gerontology is defined as the scientific study of aging and of the older population. This dual focus on processes of aging and on the characteristics, conditions, and circumstances of older people is at the heart of the field of contemporary gerontology.

Although the distinction is not always clear in practice, gerontology's concern with the scientific study of aging and old age differs from a related field—geriatrics. Geriatrics is the branch of medicine concerned with the treatment and management of diseases and illnesses (e.g., hearing loss, osteoporosis, dementia) that are more prevalent in old age than in the early or middle years. Thus, a geriatrician might be concerned with whether surgical procedures will reverse hearing loss or how an assistive device such as a hearing aid can compensate for declines in a person's ability to hear. A gerontologist might be interested in studying the causes of hearing loss, whether it occurs with greater frequency among older men or older women, and understanding the effects that declining auditory acuity have on an individual's mobility, interaction, and enjoyment of life. Put another way, geriatrics focuses on the clinical diagnosis and treatment of medical conditions that typically occur during the later years, while gerontology involves the scientific understanding of the causes, distribution, and consequences of these conditions.

Gerontological perspectives on aging and old age

Gerontology involves gaining a scientific understanding of processes of aging, processes that take place simultaneously on several levels. Aging occurs at the biological and physiological levels, for example, as the ability of cells to replicate themselves decreases with aging or as respiratory and cardiovascular systems typically become less efficient. Aging is also characterized by a series of interrelated psychological processes that may manifest themselves in changes in the speed with which information is processed or in changes in short-term recall. Aging is also a social process reflecting sequences of roles assumed throughout life and transitions from one role to another (e.g., from employee to retiree, from parent to grandparent, from spouse to widow). When we think of someone as "growing old," we are speaking of the outcomes of these and other processes that take place simultaneously, but at different rates for different people. A thirty-five-year-old grandmother or an eighty-year-old "master" athlete whose cardiovascular system is functioning at the level of a forty-year-old illustrate how processes of aging may vary from one individual to another.

Although we most often think of aging as an individual phenomenon—as what happens to persons as they grow older—it is also true that both aging processes and what constitutes old age are socially defined or socially "constructed." They are the product of historical, social, political, and economic forces. For administrative purposes, for example, when someone "becomes" old varies widely. One needs to be at least sixty-five years old to be eligible to receive full Social Security benefits (although this changed in 2002, when the eligibility age began to climb gradually to sixty-seven) and sixty to be eligible for programs and services under the Older Americans Act, but only forty to be covered under the provisions of the Age Discrimination in Employment Act. How we conceive of the capabilities of older persons also varies from one time to another. A sixty-five-year-old might be considered too old to work during a recession when unemployment rates are high, but that same person may be a highly desirable employee when the economy is booming, unemployment rates are low, and labor in short supply. As a stage of the life course, old age during America's colonial period was a far different experience from what it is during the first years of the twenty-first century and from what it probably will be when the entire baby boom generation (born between 1946 and 1964) has reached old age in the year 2030. What it is like to be old also varies from one group to another within a society, just as it varies between societies with different cultural traditions. At any particular time, the financial situation of a typical seventy-five-year-old African American woman will differ dramatically from that of a typical seventy-five-year-old white male. And the intergenerational experience of living in a Japanese family, with its tradition of multigenerational living arrangements, will differ from that of the American family where the norm has been "intimacy at a distance."

Because aging is a multilevel passage and because old age is socially constructed, the study of aging and of old age necessarily relies on the contributions of a number of scientific disciplines. For this reason, gerontology is considered a multidisciplinary and interdisciplinary field of inquiry, and professional organizations such as the Gerontological Society of America count among their members researchers and scholars from a wide variety of disciplines.

In the basic sciences, research on the biological aspects of aging is being conducted in such fields as biochemistry, cellular and molecular biology, endocrinology, genetics, immunology, nutrition, pathology, pharmacology, and physiology. Medical and health scientists from specialties such as cardiology, neurology, oncology, and orthopedics are studying the causes, consequences, and treatment of illness and disease; the epidemiology (distribution) of physical well-being; and factors associated with the use of health services by older persons. Social and behavioral research in gerontology similarly includes contributions from scientists with many different disciplinary backgrounds: anthropology, demography, economics, geography, history, political science, psychology, public health, sociology, and statistics. Our understanding of aging and the experience of being an older person is also enhanced by the work of scholars from humanities disciplines such as art, literature, music, philosophy, and religion. Gerontological knowledge has benefited, too, from research conducted by investigators from a variety of professions, such as architecture, nursing, physical therapy, and social work.

Gerontology, then, is a multidisciplinary and interdisciplinary area of scientific inquiry dedicated to increasing our understanding of aging and old age. But just as gerontology comprises a wide array of disciplines permitting research at the intersections of two or more traditional fields, its boundaries are flexible in another important way. We have learned that the nature of old age is often a product of earlier life experiences and that processes of aging begin long before one is old. This recognition has led gerontologists to begin to take a longer view of factors that affect aging and old age and to attempt to locate and identify influences that occur in earlier stages of life. Such an approach is variously known as a life course, life span, or life cycle perspective, and it has drawn our attention to the ways in which late life characteristics may have their origin in events occurring long before old age. Glen Elder, for example, has shown that the current attitudes and values of older persons were shaped by their experience during the Great Depression. And in a fascinating project known as the Nun Study, autobiographies written by nuns when they first entered a convent, at an average age of twenty-three, were examined for their linguistic ability or idea density. Over sixty years after the autobiographies were written and upon postmortem examination of the brains of deceased nuns, the idea density scores from early life were highly correlated with the presence and severity of Alzheimer's disease in late life (Snowdon, Greiner, and Markesbery). Studies such as these have made gerontologists increasingly aware of the need to examine early antecedents of late-life behaviors, characteristics, and circumstances.

Twentieth-century advances in the gerontological perspective

Foreshadowings of the storyline of twentieth-century gerontology are plentiful. Early Egyptian, Greek, and Roman commentaries on the course of life were known and carefully read by the first of the modern gerontologists. Cicero's De Senectute and Soranus of Ephesus's Gynaecia and his Acute Disease and Chronic Disease were frequently echoed. For example, Jean-Martin Charcot's examination of pathological causes of aging captured in his Diseases of the Elders and Their Chronic Illnesses (1867) (translated into English in 1881) and the early chapters of G. Stanley Hall's Senescence (1922) recounted descriptions from ancient medical tracts.

The decades on either side of the dawn of the twentieth century resounded with innovative efforts to discover first the pattern, then the laws, and finally the causes of aging. Each was seemingly mindful of Adolph Quetelet's 1842 declaration that "Man is born, grows up, and dies, according to certain laws that have never been properly investigated" (quoted in Achenbaum, p. 35). In France, Charcot's search for pathogens associated with aging was particularly influential. In England, Francis Galton sampled nine thousand visitors to the International Health Exposition of the 1880s to identify changes in physical characteristics. In Russia, Botkin surveyed three thousand almshouse residents in an effort to differentiate normal from pathological aging.

In the United States, Charles Minot blended Charcot's focus on cellular changes with those of nineteenth-century cytologist August Weismann and formulated a kind of a proto wear-and-tear theory that saw aging in terms of entropy and fatigue states. The field was given sharper focus with Metchnikoff's 1903 coinage of the word gerontology. Metchnikoff, who was by then director of the Pasteur Institute, focused his own explorations on ways to ward off infectious autotoxicity induced by phagocyte processes (leukocytes that ingest and destroy other cells) carried by intestinal bacteria. He advanced his prescription for hefty helpings of yogurt to quell intestinal disorders thought to engender the debilitations of age in popular and scientific publications and was awarded the Nobel Prize in 1908 for his treatises The Nature of Man (1903) and The Prolongation of Life (1908).

Thus stimulated, basic biological and physiological research proceeded apace, focusing on such disparate topics as environmental and public health issues, physiological changes, lesions, and cellular-level breakdowns. In 1909, Ignatius Nascher broke ranks and proclaimed that however prevalent pathology might be, old age is not defined by pathological change. Nascher was a true interdisciplinary scientist. Stressing the importance of what might now be called social epidemiology, he dispatched teams of investigators in the New York City area to gather data he then analyzed, using statistical averages to define typical conditions and to contrast one social category with another. With G. Stanley Hall's compendium Senescence (1922), the basic parameters of modern gerontology were set as an array of behavior factors and were added to the biological substrate already enunciated. Hall's approach was also significant in that he emphasized positive attributes thought to accompany the aging process (Hendricks and Achenbaum).

Publications: hallmarks and benchmarks

During the early decades of the twentieth century, interest was piqued then quickened again. In 1905, the Journal of the American Medical Association printed Stockton's "The Delay of Old Age and the Alleviation of Senility," and the next year Marshall Price's "Ancient and Modern Theory of Old Age" appeared in the Maryland Medical Journal. The most influential of these early publications was undoubtedly Nascher's 1909 article in The New York Medical Record titled simply "Geriatrics," followed five years later by his volume Geriatrics: The Diseases of Old Age and Their Treatment, Including Physiological Old Age, Home and Institutional Care, and Medico-Legal Relations (1914). He coined the term geriatrics to describe a clinical focus and single-handedly launched a new medical specialty. During the same period, Lee Squier's Old Age Dependency in the United States (1912) joined Nascher's publications and stands as one of the early efforts in the United States to survey the conditions of old age. These watershed contributions helped lead to the inauguration of a regular geriatrics section in the Medical Review of Reviews in 1917 to promote professionalization of the study of aging. Further impetus came when the Scientific American published Genevieve Grandcourt's "Eternal Youth as Scientific Theory" in 1919. Nascher's eye-catching article "Why Old Age Ends in Death" appeared the same year in the Medical Review of Reviews.

With G. Stanley Hall's publication of Senescence, the behavioral sciences were given clarion voice in the discussion of the causes and implications of aging. Hall was noteworthy because he melded basic research with practical interventions and a critique of societal arrangements. With the publication of Edmund Cowdry's edited handbook, Problems of Aging (1939), the broad parameters of gerontological inquiry were pretty well drawn (Hendricks and Achenbaum). Accompanied by financial support by the Josiah Macy Foundation and endorsements from the National Research Council's medical sciences division, Cowdry assembled the best minds of the era to launch a unified fusillade at the problems of aging. Cowdry's encyclopedic reference, which appeared in a second edition in 1942, provided the first widely heard call for a multidisciplinary approach and helped create the collective consciousness of biomedical and behavioral cross-linkages within contemporary gerontology and geriatrics.

Learned societies and other organizational events

A series of organizational events ran parallel to the many scholarly and scientific publications. Together they helped merge gerontology into the scientific mainstream and contributed to the professionalization of the enterprise. No doubt it was fortuitous that Metchnikoff had become affiliated with the Pasteur Institute in Paris in 1888, for his associates there contributed to his thinking just as he contributed to theirs. The seed was fertile and one of his students, V. Korenchevsky, went on to establish the International Club for Research on Ageing in England, succeeded in 1939 by the British Society for Research on Ageing. The club served as a learned society providing scholarly forums to present and exchange ideas. When Korenchevsky came to the United States in 1939 to create a North American branch, his efforts were virtually anticlimactic. Organizational efforts to promote analysis of aging had appeared on the national agenda as early as 1908 as part of President Theodore Roosevelt's conservation agenda as formulated by the Committee of 100. Members of that group later established the Life Extension Institute in 1914 to promote inquiry into the causes of illness and death. The New York Geriatrics Society was founded in 1915 and other comparable state-based organizations proliferated in short order.

Aging sessions in one guise or another appeared as part of the annual meetings of the American Psychological Association by the turn of the century and other learned societies followed suit. In 1917, the National Conference of Social Work scheduled a plenary session and invited Nascher and a number of speakers to participate in a scholarly exchange on pathological models of aging and to suggest appropriate efforts for social workers.

Attention to the implications of aging grew in the period immediately after World War I. A popular magazine, Voix du Retraite, appeared in Paris in 1919 and the Swiss Foundation for the Aging began publishing its Pro Senectute in 1923. In 1928, a Japanese organization for the aged, Yokufukai, launched initially in 1925 to help older victims of a major earthquake, began disseminating the Yokufukai Geriatric Journal, succeeded in 1930 by Acta Gerontologica Japonica. In Eastern Europe, the magazine Problems of Ageing (printed in five languages) appeared in 1935 under the auspice of the International Institute for the Study of Old Age and the Romanian government. Meanwhile, in the Soviet Union, I. Fisher and P. Yengalvtchev launched a series of empirical investigations and publications on the role of physical condition, mental status, and environmental factors in promoting longevity. Their efforts led to a major conference in 1938 in Kiev that stands as a milestone for bringing together researchers from Eastern Europe. International interest was accelerating and the number of contributors and publications spread around the globe.

In the same period a number of philanthropic foundations with interests in public welfare and scholarly advancement sponsored various conferences and workshops that led to some of the publications noted above. Among them the W. K. Kellogg Foundation, the Russell Sage Foundation, the Carnegie Corporation, the Josiah Macy Foundation, and the Rockefeller Foundation stand out. None of the efforts were more luminous that the Woods Hole conference that led to Cowdry's Problems of Aging. The inter-disciplinary message Cowdry and his coauthors promulgated did not gain sweeping acceptance but by 1940, Edward Stieglitz, a newly appointed clinician with the Public Health Service, suggested that the proper study of aging should incorporate no less than geriatrics, the biology of senescence, and sociological perspectives on aging populations. Nathan Shock took over from Stieglitz and continued the same mission for the next thirty years. The same year that Stieglitz began promoting a truly interdisciplinary focus, the National Institutes of Health, founded in 1930, also incorporated a Unit on Gerontology with an edict to enhance knowledge of aging processes.

Although the American Geriatrics Society was founded in midst of World War II (1942), the war years slowed many further developments. However, within a year of war's end, what is now called the Gerontological Society of America was established, with the initial issue of the Journal of Gerontology appearing in 1946. Under the auspices of the International Association of Gerontology, which was founded in 1950, international scientific congresses are held to bring together researchers from around the world in an open exchange of ideas.

Despite the publication in 1945 of two important books—Leo Simmons's The Role of the Aged in Primitive Societies and Oscar Kaplan's Mental Disorders in Later Life —Otto Pollack declared in Social Adjustment in Old Age (1948) that insights into aging from the social and behavioral sciences lagged behind those of medicine and biology. Soon a breakthrough contribution began to change that picture. Together with her colleagues from the University of Chicago, Ruth Cavan surveyed three thousand older persons and published the results in Personal Adjustment in Old Age (1949). It was only the first of the many contributions made by the Committee of Human Development at the University of Chicago. Perhaps not as well remembered as the famous Kansas City Studies of Adult Aging, or many of the early, seminal contributions of Bernice Neugarten, Ethel Shanas, Robert J. Havighurst, Robert Burgess, Elaine Cumming, William Henry, and others, it nonetheless paved the way for the shape of social gerontology. By the time Elaine Cumming and William Henry published their disengagement interpretation of the results of the Kansas City Studies in their Growing Old (1961), gerontology had come of age and advances were occurring along many fronts.

From that point on, the relatively narrow flow of information spread out across the landscape. Programs and certificate training sprang up in California, Michigan, North Carolina and around the country. By the 1960s the Gerontological Society transformed a newsletter into its second journal, The Gerontologist, and the first of the White House Conferences on Aging was held. Out of that conference came the establishment of an Office on Aging (under the leadership of Donald P. Kent), later the Administration on Aging, and the momentum that led to both the passage of Medicare and Medicaid (1965) and support via the Older Americans Act for the development of education and training programs in gerontology in the late 1960s and 1970s. The last of the building blocks came in 1975 with the inauguration of the National Institute on Aging to oversee basic research in a wide array of disciplines and to train future researchers. Significant publications continued to emerge, including Clarke Tibbitts's Handbook of Social Gerontology (1959), the three-volume Aging and Society series under the leadership of Matilda White Riley, and the five editions of the Handbook of the Biology of Aging, Psychology of Aging, and Aging and the Social Sciences under the general editorship of James E. Birren.

Teaching and training

The steadily increasing recognition of the importance of gerontology is reflected in its growing presence in the curricula of institutions of higher education in the United States. In the 1950s, coursework on aging was offered on only a small number of campuses. Data collected in 1957 showed that only fifty-seven colleges and universities offered credit courses in gerontology. The number of campuses with courses on aging increased to 159 in 1967, 607 in 1976, and 1,335 in 1985. By 1992, when the last major survey was conducted, it was estimated that gerontology instruction was offered on 1,639 campuses, or at 55 percent of American institutions of higher education. Of these campuses with credit instruction in 1992, the average number of courses in gerontology was 9.4 and over 40 percent offered a structured program of course-work in gerontology, geriatrics, or aging leading to the awarding of a degree, certificate, specialization, concentration, minor, or some other form of credential (Peterson, Wendt, and Douglass.

An important development in graduate education was the establishment of the first Ph.D. programs in gerontology in the late 1980s and early 1990s. A long and continuing debate has centered on the question of whether gerontology is better viewed as a field of specialization or as an emerging academic discipline. Those taking the position that gerontology is a field of specialization contend that doctoral work should take place in one of the more traditional disciplines (e.g., biology, psychology, sociology), but with an emphasis on aging in coursework and research. Those holding the view that gerontology has reached a stage of maturity in its theories, methods, and content argue that doctoral-level work leading to a Ph.D. in gerontology is justified. The merits of each of these positions aside, academic programs leading to a Ph.D. in gerontology existed at a handful of American universities at the outset of the twenty-first century. The debate about whether gerontology is a specialty or a full-fledged academic discipline will doubtless continue, but the emergence of Ph.D. programs attests to the increasing recognition of its importance.

The most comprehensive list of college and university programs in gerontology, geriatrics, and aging has been compiled by the Association for Gerontology in Higher Education (AGHE, now an Educational Unit of the Gerontological Society of America). In its seventh edition, the Directory of Educational Programs in Gerontology and Geriatrics (Stepp) provides detailed information on the content, focus, and type and level of credential offered in close to eight hundred programs in the United States, Canada, and other countries.

Applied gerontology

Knowledge accumulated from scientific research on the biological, physiological, psychological, and social processes associated with aging adds to our basic understanding of the human condition. But gerontological research serves another essential purpose. By learning about the nature of aging and old age, we are in a position to use the knowledge to improve the quality of the later-life experience. Applied gerontology emphasizes the translation of basic research into the development of services, programs, and interventions for the betterment of the older population. Basic biological research not only illuminates the mechanisms underlying this aspect of the aging process, but also offers clues that have the potential to slow down or reverse deleterious outcomes. Knowing how physiological and sensory processes change with aging provides valuable information that can be used to design environmental modifications to enhance the functional ability of older persons. Gaining a scientifically sound appreciation of the extent and nature of family caregiving can counter the myth of abandonment and allow for the development of an appropriate blend of supportive services to help families cope with the stresses of caring for a frail relative. Studies on the barriers and obstacles people encounter in accessing services and programs enable us to consider ways to restructure their delivery and enable health and human service providers to better meet the needs of target populations.

Gerontology makes a distinction between life expectancy—how many more years one can expect to live at a given age—and "active" life expectancy—or how long one can expect to function well prior to the onset of debilitating conditions. This distinction serves to focus attention on the quality of late life and not simply its quantity. In this sense, the fundamental and complementary objectives of basic and applied gerontology might best be summarized as the pursuit of scientific knowledge to promote and extend the active life expectancy of older persons or, as in the motto of the Gerontological Society of America, "to add life to years, not just years to life."

Stephen J. Cutler Jon Hendricks

See also Aging; Geriatric Medicine; Careers in Aging; National Institute on Aging; Prolongevity.

BIBLIOGRAPHY

Achenbaum, W. A. Crossing Frontiers: Gerontology Emerges as a Science. Cambridge, U.K.: Cambridge University Press, 1995.

Elder, G. H. Children of the Great Depression, 25th Anniversary ed. New York: HarperCollins, 1998.

Hendricks, J., and Achenbaum, W. A. "Historical Development of Theories of Aging." In Handbook of Theories of Aging. Edited by Vern L. Bengtson and K. Warner Schaie. New York: Springer Publishing Co., 1999. Pages 21–39.

Metchnikoff, É. The Nature of Man. New York: Putnam and Sons, 1908. (First published in France, 1903).

Peterson, D. A.; Wendt, P. F.; and Douglass, E. B. Development of Gerontology, Geriatrics, and Aging Studies Programs in Institutions of Higher Education. Washington, D.C.: Association for Gerontology in Higher Education, 1994.

Pollack, O. Social Adjustment in Old Age. New York: Social Science Research Council, 1948.

Snowdon, D. A.; Greiner, L. H.; and Markesbery, W. R. "Linguistic Ability in Early Life and the Neuropathology of Alzheimer's Disease and Cerebrovascular Disease: Findings from the Nun Study." In Vascular Findings in Alzheimer's Disease. Edited by Raj N. Kalaria and Paul Ince. New York: New York Academy of Sciences, 2000. Pages 34–38.

Stepp, Derek D., ed. Directory of Educational Programs in Gerontology and Geriatrics, 7th ed. Washington, D.C.: Association for Gerontology in Higher Education, 2000.

GLAUCOMA

See Eye, aging-related diseases

GERONTOLOGY

Gerontology, the study of aging, has become a major focus of attention in science and the professions. With increasing life expectancy and falling birth rates, populations are getting older. Increases in life expectancy in both developed and developing countries and increased needs for services for older persons have contributed to a growing volume of research and education on both basic and applied aspects of aging. Geriatrics, the branch of medicine that treats the clinical problems of late life, is also an area of expanding professional activity. Both gerontology and geriatrics emerged as disciplines immediately after World War II with the establishment of professional societies and specialized journals. Why it took so long, compared with other fields, for academic and professional interests in aging to emerge is an interesting question to pursue.

There have always been speculation and cultural myths about aging and the association of death with advanced chronological age. Gerald Gruman has described many myths about death and aging from ancient times to about 1800. The common interpretation in the Middle Ages was that death was either the outcome of humankind's fate as punishment for sin or an outcome of cosmic forces that were insurmountable. The growth of science in the nineteenth century was accompanied by the conviction that all phenomena of nature were governed by natural laws, and that these laws can be discovered through scientific investigation. The point of view that aging was not a supernatural phenomenon, knowable and explainable by study, was fully expressed by the Belgian mathematician, statistician, and astronomer Lambert Quetelet (1796–1874). In 1835, Quetelet wrote: "Man is born, grows up, and dies, according to certain laws which have never been properly investigated, either as a whole or in the mode of the mutual reactions" (Quetelet, 1968). Quetelet reviewed data on mortality in relation to age, sex, urban, rural, and national differences and found that the duration of human life varied according to the environments in which people lived.

An international exhibition on health in London in 1884 extended further interest in how differences in age affect human functions. The exhibition was sponsored by Francis Galton (1822–1911), a cousin of Charles Darwin. Galton had a broad background in mathematics medicine, psychology, and anthropology. At the exhibition, he took measurements of seventeen different bodily functions, including hand strength, hearing, vision, speed of movement, and vital lung capacity. Over 9,337 males and females were measured. Since Galton was exposed to a large mass of data, and given his back ground in mathematics, he was able to develop the first quantitative measure of the degree of association between two variables, such as age and strength.

Gerontology requires the support of mathematics and statistics to identify and compare the complex sources of variance that influence human aging. Quetelet and Galton were pioneers in creating a quantitative basis for gerontology and replacing older myths. Another contributor to the quantitative approach to aging was Benjamin Gompertz, a British actuary, who, in 1825, described the relationship of mortality to age as an accelerating curve described by exponential equation. The fact that mortality data could be described as an exponential equation did not itself explain why mortality is related to age. It was, however, an early step toward bringing science into discussions about aging.

Similarly, relating health, disease, and changes in function to chronological age does not reveal the causal variables. Modern gerontology recognizes that organizing data by age is but a first step toward explanation. To understand the process of aging and the changes that occur as people age, the causal variables must be understood.

The term "gerontology" was introduced in 1903 by Elie Metchnikoff, a Nobel laureate and professor at the Pasteur Institute of Paris. In America, the emergence of gerontology as a scientific movement can be traced to a small group of leaders who, in the mid-1930s, recognized that the health of the American population was undergoing a change from domination by infectious diseases to chronic diseases. The Gerontological Society of America was founded in 1945, and the International Association of Gerontology about five years later.

THE BEGINNING OF MODERN GERONTOLOGY

The concerns of public health and medicine in the early years of the twentieth century were focused on the major causes of death at that time, the infectious diseases. Disease was generally regarded as a result of an invasion of the human body by a foreign organism whose influence had to be destroyed. As chronic diseases—heart disease, stroke, cancer, diabetes, and others—began to replace the infectious diseases as the major causes of death, a revision of basic explanatory paradigms had to occur, since the human host was beginning to be regarded as a major element in the cause of the chronic diseases. In the mid-1930s, the Josiah Macy, Jr. Foundation, based in New York, began a series of conferences on aging. The foundation's director was Dr. Ludwig Kast, who believed that degenerative diseases were a manifestation of the process of aging. The foundation had supported studies of degenerative diseases, but Kast encouraged research on aging itself. Thus, work on heart disease was examined in relation to the physiology of aging.

The foundation encouraged E. E. Cowdry, a professor of cytology at Washington University, to organize a book that would embrace not only the biomedical aspects of aging, but include social, psychological, and environmental influences as well. Cowdry's book, Problems of Ageing, was published in 1939. The foundation continued to sponsor conferences on aging, which led to the establishment of The Club for Research on Aging, in New York. By 1940, thinking about aging was becoming more sophisticated. Reflecting the thinking of the times, the U.S. Public Health Service organized a multidisciplinary conference in 1941 on mental health aspects of aging. At the same time, the Surgeon General of the U.S. Public Health Service established the Section on Aging within the National Institutes of Health. Thus, leadership in public health helped to establish aging as an important research topic.

AGING AND EVOLUTION

The nineteenth-century interest in the biological evolution of species, expressed by Charles Darwin (1809–1882), and Alfred Russel Wallace (1823–1913), was also accompanied by an interest of a small number of biologists in fitting aging into an evolutionary paradigm. It is not a simple step to account for the natural selection of late-life features, since they appear past the age of reproduction, and therefore out of direct reach of the pressures of natural selection. In 1957, Peter Medawar (1915–1987) reasoned that selective pressures for survival features were maximum at the time of reproduction and then declined. He described this as a result of selective pressures to create a "precession" of positively selected characteristics toward the age of maximum reproduction and a "recession" after the age of reproduction. Natural selection is therefore presumed not to affect late-life characteristics, and a series of unrelated characteristics may appear (e.g., Alzheimer's disease, Parkinson's disease, and other life-limiting conditions). Such diseases are presumably out of reach of selective pressures. This point of view is associated with the idea that life after reproduction is subject to random degradation of the well-functioning organism.

However, this reasoning need not exclude the possibility of indirect selection in which a late-life trait like intact memory and reasoning could operate to meet threats to tribal survival in preliterate societies. That is, tribes that had long-lived elders with intact memories of meeting the problems of families, floods, and warfare could have greater chances of survival. This has been described as a "counterpart theory," in which late-life characteristics of older persons influence the selective survival of the young and those of reproductive age who are dependent upon them for survival (Birren, 1964).

An impressive amount of data has been gathered on the life spans of a wide variety of different species. The comparative biology of aging suggests that most have relatively fixed upper limits of the lengths of life. Particularly, the lengths of life of vertebrates are relatively fixed in relation to each other (e.g., mice, rats, cats, dogs, horses, and primates). Evidence on the comparative longevity of primates suggests that if the environments are controlled to minimize the influence of predators and other influences, the average length of life, and the maximum length of life of members of a species, can be increased. Thus, while many primates may have life-limiting genetic traits, the expression of inherited traits is modulated by the environments in which they are expressed.

An issue facing the translation of the comparative biology of aging into principles about human mortality and morbidity is why different species have characteristic lengths of life. The quest is to identify common or shared interspecies genetic determinants that may have evolved. In contrast, examining individual differences in longevity within a species (intraspecies variability) can involve different traits, or the interaction of traits with the characteristics of a particular environment. Within a species there appear to be simultaneous positive and negative factors contributing to length of life.

ADVANCES IN LIFE EXPECTANCY

Dramatic advances in life expectancy took place in the twentieth century. Life expectancy at birth for the U.S. population rose from 47 years in 1900 to 77 years in 2000. Clearly, genetic selection could not have operated so quickly, and nongenetic factors had to be the cause of this startling increase in life expectancy. A different pattern of the major causes of death emerged during the century. In 1900 the five major causes of death were: (1) pneumonia and flu, (2) tuberculosis, (3) diarrhea and intestinal disease, (4) heart disease, and (5) stroke and brain lesions. By 2000, the five major causes were: (1) heart disease, (2) cancer, (3) stroke and brain lesions, (4) lung disease, and (5) accidents. Presumably, a cleaner environment, in terms of improved water supplies and improved sewage disposal, together with the discovery and use of vaccines and antibiotics, contributed to the spectacular fall of infectious diseases as causes of death. Also, improvements in the transport of fruits, vegetables, and other foods led to the elimination of seasonal dietary deficiencies. General improvements in diets also contributed to the improvement in life expectancy. But the rise in lung disease and cancer as causes of death suggests there may have been simultaneous environmental deficits occurring parallel to these improvements. At any particular time in history there may be simultaneous positive and negative influences on aging, life expectancy, the incidence of particular diseases, and the quality of life.

One of the largest correlates of life expectancy is food intake. In 1935, MacCay, Crowell, and Maynard reported that dietary restriction promotes longer life in mice. Since that time, the effects of restricted dietary intake have been reported in many studies. Little early attention was given to the fact that in addition to the life extension effects of dietary restriction in small animals, many diseases to which the animals are disposed were delayed in their onset. There being no available explanation or mechanism to explain this delay of appearance of diseases, it received little attention. However, in 1954, Denham Harman proposed that free radicals can contribute to the aging of organisms. Free radicals refer to molecules that have one or more electrons in their outer orbits that can interact with DNA, proteins, and unsaturated lipids in cell membranes. They appear to be very reactive at all levels in an organism. In recent years, the identification of oxidant damage from free radicals has led to acceptance of the view that oxidant damage can modulate the expression of the genetic traits of animals, including humans.

CONTEMPORARY GERONTOLOGY

Undoubtedly there have been many contributing factors to the relatively slow emergence of gerontology as a subject of study. The implications of aging as a natural phenomenon were to some extent threatening to some religious or philosophical convictions. The large number of children born early in the twentieth century gave rise to the professional specialties of pediatrics, child psychology, and child psychiatry. K. F. Riegel (1977) did a quantitative study of publications in the psychology of aging and found that such publications increased exponentially after 1950, fifty years after child psychology became an established academic field of study.

Children's susceptibility to infectious diseases contributed to a health focus on early life, and little attention was given to phenomena of aging and later-life morbidity. Also, the dominant views of medicine in the early twentieth century were focused on single variable explanations of disease and on external causes. When the focus shifted, in the late 1930s, to include the chronic diseases typical of late life, aging tended to be attributed to single causes (e.g., "you are as old as your arteries"). Specific organ failures were examined in detail, and interactive physiological influences were overlooked. In particular, the nervous system was largely neglected in thinking about aging, although it is a basic regulator of bodily functions.

Economic factors undoubtedly played a role in the slow emergence of gerontology as an area of study. In the early twentieth century, few institutions, private or nonprofit, were devoted to the care and treatment of the aged. Pensions, social security, disability insurance, retirement communities, assisted living facilities, adult education programs, and many other programs emerged later, increasing the need for knowledge about the characteristics of the older population. As the institutional lag in serving older persons began to ebb, research on aging began to grow.

The elevation of the Section on Aging to the National Institute on Aging in 1975 by the U.S. Public Health Service within the National Institutes of Health was a landmark in the growing support of research on aging. Gerontology was coming of age. Handbooks on the biological, psychological, and social science aspects of aging made their appearance in 1977, providing further evidence of the significant growth of the study of aging after 1950.

The complexity of aging as a set of interacting phenomena presented early life scientists with questions that could not easily be answered with the methodology of the time. In the past it was much easier to study single organs and their functions in isolation than to study them in an aging human organism. Important shifts in the major causes of death over the last hundred years indicate that aging is a highly dynamic phenomenon. Early studies of heart disease, however, did not recognize the contribution of the social environment and the behavioral dispositions of individuals as contributing factors to disease. For example, bereavement was found to have an effect on the mortality of the surviving spouse, increasing the awareness of the complex interactions in aging.

AGING AS AN ECOLOGICAL PHENOMENON

In the early twentieth century, the realization began to grow that aging is also an ecological phenomenon. Longitudinal studies of human populations in the latter part of the twentieth century have provided considerable evidence of the range and plasticity of human variability in the way aging is manifest. Since experimental studies of human longevity and aging are not morally possible, longitudinal studies have been important in providing evidence of the relative effects of environment and heredity on mortality, morbidity, and functional characteristics. Further advances in our understanding of human aging have been provided by longitudinal studies of identical twins reared together or apart over their life spans. No longer are simple assumptions acceptable about the contributions of "nature" and "nurture" to human aging. Contemporary questions focus on the relative magnitudes of different influences. The lifespan identical twin studies of the Karolinska Institute in Stockholm, Sweden, have provided evidence that both genetic and environmental factors influence individual variability in the expression of late-life characteristics. Such findings make it impossible to explain human aging solely in terms of genetic inheritance or environmental influences.

A strong force in attributing human aging to genetic inheritance is the fact that the various species have characteristic lengths of life relative to one another. Even if one increases the length of life of rats by 100 percent, they still do not live as long as cats or dogs. Thus there is a hierarchy of life spans, which presumably has evolved by natural selection of animals exposed to different environmental pressures such as availability of food, extreme temperatures, and predation.

To answer questions raised by gerontology about how long people live—and how well they live—it is clear that some answers will come from the bottom up; from the study of elemental subcellular and cellular biological processes. Other answers will come from the top down; from the organization of our behavior through experience and the interaction of "software and hardware" in the nervous system. For example, smoking and high alcohol consumption have been found to shorten life and predispose people to diseases of the heart, lungs, and liver. Behavior and lifestyle also have an effect on health. The concept of "selfregulation" has been introduced to express the higher level of control exercised by the nervous system as a result of learning.

People with higher levels of education appear to have a greater capacity for self-regulation, and they live longer, on average. Being aware of different sources of information, they tend to seek medical assistance sooner and have more medical diagnoses than the less educated, and they spend fewer days in hospitals. Those with less education tend to initiate interventions only when there are health crises accompanied by a higher risk to survival. In contrast, the highly educated seek early interventions, when desired outcomes are more likely.

The "software" of the nervous system can also acquire different tendencies to self-destruction through suicide in different societies. Suicide is about the ninth leading cause of death in America, but is more common in Hungary and Finland. In the history of Japan, ritual suicide (hara kiri) was a justified accompaniment of loss of face or disgrace. The tendency to violence and homicides also varies among different cultures, which again illustrates the interaction of the environment and length of life. While the major causes of death are chronic diseases, culture modulates our disposition to such illnesses, as well as to suicide and homicide.

In the past, religions have placed a high emphasis on individual fates being determined by a higher power. Prayer has therefore been assumed to have great intervention potential. In recent years there has been more exchange between the cultures of religion and of science. The result has been research showing that participation in religious activities does indeed have beneficial effect on aging. Some of the benefits may result from selection of the subjects studied—better adjusted and more socialized adults may be more likely to belong to a religious community. Also, a belief in a higher power by itself may reduce stress and promote health. Regardless of the preferred interpretations of causality in the relationships of longevity, health, lifestyle, culture, spirituality, and religion, the fact that information is being gathered and exchanged is likely to be of use in improving human well-being in later life.

This complex picture defines the subject of gerontology. The study of the biology of aging exists at many levels, from cell parts to whole organisms. In the case of humans, the various critical organs, such as the heart, liver, kidneys, immune system, and the nervous system, have often been studied in isolation. There are both interactions and factors, however, that effect all organs. One of the general factors coming into prominence is the energy-producing component of cells, the mitochondria. Energy is needed by the whole organism for the development, maintenance, and repair of organs, tissues, and cells. Aging of the mitochondria can have widespread consequences throughout an organism. Clearly, new knowledge about aging must be sought at all levels—biological, psychological, social, and cultural. Risk factors are being identified that provide insights into the causes of late-life disabilities and provide clues about ways to ameliorate or control their consequences.

New theories of aging are being advanced as our data and our understanding of the human organism improves. One of the earliest theories was that of Raymond Pearl (1879–1940), who, in 1928, held that the metabolic rate of different species underlay the difference in their length of life. Longevity, he proposed, is inversely proportional to the metabolic rate per unit of body mass. Presumably animals are born with a capacity for a fixed amount of irreplaceable energy. Pearl viewed rate of energy expenditure as predictive of the length of life of a species.

Energy is needed at all levels of an organism, and it ultimately depends upon the functioning of the mitochondria. Thus, aging of the mitochondria can have widespread consequences throughout an organism. The fact that the mitochondria has its own DNA that lies outside of the DNA on the chromosomes, is important. The mitochondrial DNA is transmitted to the fertilized ovum solely from the mother. Is has a structure different from the chromosomal DNA, but it too is susceptible to the effects of damage from oxidants. One general consequence of the metabolism of large amounts of food is the production of oxidants that can interfere with the process of energy release in the cells of the body's critical organs and reduce their level of functioning. In a sense, this is a general environmental interference with genetic expression in the cells of vital organs of the body.

The oxidative damage done by free radicals may also interfere with the signaling or communication between biological systems, which may include immune system in older persons, and its failure to recognize the necessary proteins of a body and attack them. Recent work suggests that the body's inappropriate production of oxidants and the capacity of the body to control oxidative stress is a key feature of aging and the length of life (Finkel and Holbrook, 2000). Also, there is the question of the extent to which the life-limiting effect of oxidant damage results from the oxidant level itself, or from a change in the capacity of the organism to manage it. In either case the result may be individual organ failure or a life-limiting disease.

TRENDS

Gerontology continues to be an expanding field of study and a rising area of public interest. Academic positions are increasing, and even more increases are seen in private-sector employment in service areas such as retirement housing, assisted living, exercise programs, health care, adult education, travel, and entertainment. Also expanding are training activities related to aging in the professions; and new academic and professional journals are appearing. One consequence of this rapid growth is a rise in research on specialized aspects of aging. The rapid growth in published literature has been accompanied by a lag in integrating data from different disciplines. There is a need for integration of information within and across academic disciplines. One might expect to see more emphasis on meta-analysis of many studies, not only on narrow topics, but on broader issues related to genetic, environmental, and behavioral factors.

Many of the factors influencing aging have lower and upper limits that have yet to be defined and measured. The benefits of exercise, for example, conceivably have a ceiling beyond which further activity can have negative outcomes. Such a ceiling is in contrast to the "floor" of low physical activity, which leads to disuse atrophies in the organism and can contribute to episodic risk factors such as falling. In a similar manner, cognitive activity and the use of memory have both optimum upper limits of use for maintenance of function and floor effects leading to regression of function.

As a species, humans have undoubtedly been selected for rapid and sustained physical activity to avoid predators and seek food sources. The capacity of the human nervous system for strategic control of the environment has led to a drop in the need for physical activity and for high food availability. Individuals tend to lower their physical activity when it is not needed, and to overconsume food in relation to metabolic needs. Cultural controls have to be cultivated in these areas to maximize potentials for long and useful lives, along with better health promotion and disease prevention efforts.

With the rising interest in promoting the well being of aging populations, new metaphors are being introduced to motivate people to undertake lifestyle changes. Such metaphors appear to be designed to cast a motivating optimistic aura about aging. Terms like "successful aging," "productive aging," and "vital aging" do not in themselves identify the important variables in human aging. Rather, they reflect a rising interest on the part of the research community to attract public interest to areas of research thought to be useful in an aging population. The proliferation of terms used in gerontology and in reference to aging led to the development of a Thesaurus of Aging Terminology by AARP.

The understanding of aging and the analysis of its complexity requires the consideration of many contributing variables and their interactions. It is inherently a multidisciplinary and interdisciplinary field of research. There appears to be little doubt that the twentieth century will introduce new concepts and theories about aging, and that the sciences concerned with gerontology will advance our understanding of aging and lead to further increases in life expectancy and improved quality of life.

James E. Birren

(see also: AARP; Aging of Population; Cohort Life Tables; Cohort Study; Dementia; Epidemiologic Transition; Geriatrics; Life Expectancy and Life Tables; National Institute on Aging; Physical Activity; Rates: Age-Adjusted; Rates: Age-Specific; Widowhood )

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Gerontology

BIBLIOGRAPHY

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 Élie 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.

SEE ALSO Baby Boomers; Demographic Transition; Demography; Maturation; Welfare State

BIBLIOGRAPHY

Cowdry, E. V., ed. 1939. Problems of Ageing: Biological and Medical Aspects. Baltimore, MD: Williams and Wilkins.

De Grey, Aubrey. 2003. The Foreseeability of Real Anti-Aging Medicine: Focusing the Debate. Experimental Gerontology 38 (9): 927–934.

De Grey, Aubrey. 2004. Welcome to Rejuvenation Research. Rejuvenation Research 7 (1): 1–2.

Hayflick, Leonard. 1982. Biological Aspects of Aging. In Biological and Social Aspects of Mortality and the Length of Life, ed. Samuel H. Preston, 223–258. Liege, Belgium: Ordina.

Laslett, Peter. 2005. The World We Have Lost. 4th rev. ed. London: Routledge. (Orig. pub. in 1965.)

Riley, Matilda White, Marilyn E. Johnson, and Anne Foner, eds. 1968–1972. Aging and Society: A Sociology of Age Stratification. 3 vols. New York: Russell Sage Foundation.

Shostak, Stanley. 2002. Becoming Immortal: Combining Cloning and Stem-Cell Therapy. Albany: State University of New York Press.

Bryan S. Turner

Gerontology

Gerontology is the social, biological, and psychological study of the aging process and, specifically, the elderly. It a branch of sociology that studies aging among populations internationally; monitors efforts to deal with problems arising in old age; studies social, mental, and physical changes in people as they age; and applies knowledge to sponsor policies and programs around the world.

Professionals who work in gerontology are called gerontologists. They work to educate the public about aging and to perform research and development within the area of the aging process. Gerontologists often specialize in different subfields. Some perform research on the aging process, including the environments and social structures that involve aging. Others, called applied gerontologists, work directly with the elderly on an individual and group basis to solve problems and provide information for their needs. Still other gerontologists work to coordinate and maintain administration and management programs set up for elder services. A number of gerontologists concentrate on writing books and journal articles about the elderly, along with giving presentations to the elderly. Many are employed within the college and university settings as professors and educators. Generally, however, all gerontologists have educational backgrounds in demography, nursing, psychology, sociology, or other social-type backgrounds.

Gerontology differs from geriatrics the same way that psychology is separate from psychiatry. A psychologist’s inquiries apply to general questions about how the human brain and mind work. A psychiatrist is more concerned with involving patients in a particular course of therapy. Geriatrics is a specialty within medicine concerned with treating illnesses that occur most often in the aged. Gerontology, on the other hand, considers geriatrics as part of a larger spectrum of issues that face older people, their immediate families and society at large.

In the United States, since the 1920s, a shift has been seen in the median age of the total population. On average, there has been a more rapid increase in the percentage of older people than younger ones in the country. One generation that has added many older persons to the U.S. population is the Baby Boom generation of the 1950s and 1960s—the result of soldiers returning home from World War II (1939–1945). In addition, life expectancy in the United States and in many industrialized countries of the world due to better sanitation methods, fewer childhood diseases, and a general improvement in medical care. For instance, according to the U.S. Centers for Disease Control and Prevention (CDC), in 1900 the average life expectancy for a U.S. citizen was 47.3 years, while in 2003 it was 77.5 years, in increase of over 30 years. In 2004, just one year later, the life expectancy had risen another 0.4 year (to 77.9 years) for an average person in the United States. The current world average, according to the World Bank, is about 66 years.

In the past, most elderly remained part of a family unit. However, in the 2000s, elderly persons living in households containing one of their adult offspring is at a percentage of less than 20%. In addition, not all of the elderly are in the same economic bracket, and not all will remain healthy until their deaths. Due to these circumstances and others, many elderly has additional financial problems while in their older years. Gerontologists have been researching the impact that might be felt in a community, and the cost that may be incurred by the federal government, if many of them need institutional care as they grow older. The most recent literature has been produced on developing trends, like those involving AIDS (acquired immunodeficiency syndrome) in older patients. In most industrialized countries of the world, the elderly are treated with national health plans such as Medicare, which is provided in the United States.

Even Aristotle (384–322 BC) observed the differing life spans in the animal kingdom. Since the days of the ancient Greeks, speculation about aging has gone handin-hand with the development of medicine as a science. During the 1800s, certain researchers like Belgium mathematician and sociologist Lambert Adolphe Jacques Quetelet (1796–1874) and Russian therapist and clinicist Sergei Petrovich Botkin (1832–1889)began to study populations and social patterns of aging in a systematic fashion. During the 1930s, the International Association of Gerontology (IAG) was organized. The National Institutes of Health (NIH) joined with other governmental bodies to sponsor conferences on aging during the following decade, and by 1945 the Gerontological Society of America, Inc., was established in Washington, D.C.

Aside from history, politics, and economics, more personal experiences are also investigated by a geron-tologist. The impact of death on a widow or widower,

the interrelationships of different generations within a family, and the circulation of myths about aging are also subject to qualitative research. Qualitative studies rely less on statistics than on interviews and records of emerging situations within a small group of test subjects. Coping strategies and other forms of therapy are assessed in terms of their suitability and success rates. Trends in medical research are also analyzed in terms of their impact on public opinion and their contributions towards scientific understanding of the aging process.

Attitudes toward the elderly have somewhat changed over the last few generations. Although a larger percentage of elderly are present in the population, society has become more oriented to younger people. Consequently, the plight of the elderly has been ignored in large part. Stereotypes are frequently labeled onto the elderly by the media and other groups. However, other groups such as the American Association of Retired Persons (AARP) and the National Coalition on Aging are helping to organize the elderly and to communicate their issues to the government and society in general.

See also Aging and death.

Gerontology

Gerontology is a branch of sociology that studies aging among populations internationally, and monitors efforts to deal with problems arising in old age. It differs from geriatrics the same way that psychology is separate from psychiatry . A psychologist's inquiries apply to general questions about how the human brain and mind work. A psychiatrist is more concerned with involving patients in a particular course of therapy. Geriatrics is a specialty within medicine concerned with treating illnesses which occur most often in the aged. Gerontology, on the other hand, considers geriatrics as part of a larger spectrum of issues which face older people, their immediate families and society at large.

In America the past few decades has seen a shift in the median age of the total population. On the average there have been more and more older people than younger ones in the country as time goes by. Not all of these elderly are in the same economic bracket, and not all will remain healthy until their deaths. Gerontologists have been researching the impact which might be felt in a community, and the cost which may be incurred by the federal government, if many of them need institutional care as they grow older. The most recent literature has been produced on developing trends, like those involving AIDS in older patients.

Even Aristotle observed the differing life spans in the animal kingdom. Since the days of the Ancient Greeks, speculation about aging has gone hand in hand with the development of medicine as a science. During the 1800s, certain researchers like Lambert Quetelet of Belgium and S. P. Botkin in Russia began to study populations and social patterns of aging in a systematic fashion. During the 1930s, the International Association of Gerontology was organized. The National Institutes of Health (NIH) joined with other governmental bodies to sponsor conferences on aging during the following decade, and by 1945 the Gerontological Society of America, Inc., was established in Washington, D.C.

Aside from history, politics and economics, more personal experiences are also investigated by a gerontologist. The impact of death on a widow or widower, the interrelationships of different generations within a family, and the circulation of myths about aging are also subject to qualitative research. Qualitative studies rely less on statistics than on interviews and records of emerging situations within a small group of test subjects. Coping strategies and other forms of therapy are assessed in terms of their suitability and success rates. Trends in medical research are also analyzed in terms of their impact on public opinion and their contributions towards our understanding of the aging process.

See also Aging and death.