Since the 1960s or perhaps even before, gerontologists have been developing conceptual frameworks or schema to describe ideal outcomes of the aging process. One of the most commonly used terms to describe a good old age is "successful aging", often attributed to R. J. Havighurst (1961). The concept of successful aging is central to gerontology, and the article by Havighurst appeared as the first conceptual piece in the first issue of the profession's prime publication, The Gerontologist.

Interest in successful aging has remained high through the successive decades, and peaked again with Rowe and Kahn's 1987 article in Science in which they recommended that research on successful aging should focus on people with better than average physiological and psychosocial characteristics in late life, or "successful agers" as opposed to average or "usual agers". In the early 1990s, a major set of studies on predictors of successful aging was commissioned by the MacArthur Foundation and conducted under Rowe's leadership (Berkman, et al., 1993; Seeman et al., 1994). The results have recently been featured in the New York Times (Brody, 1996), diffusing the concept into the public arena.

What do gerontologists mean by successful aging? Not surprisingly, given the ambiguity of the term "success" itself, there is no single well-accepted definition or model of successful aging that has stood the test of time. Havighurst (1961) defined it as "adding life to the years" and "getting satisfaction from life". Rowe and Kahn (1987) defined it in terms of multiple physiological and psychosocial variables. The MacArthur studies looked at outcomes pertaining to physical performance and other indicators of functional status. Ryff (1982), a psychologist, defined successful aging as positive or ideal functioning related to developmental work over the life course. Fisher (1992) interviewed 19 senior center participants age 62-85 and found that they tended to define successful aging in term of strategies for coping. Gibson (1995) stated that successful aging "refers to reaching one's potential and arriving at a level of physical, social, and psychological well-being in old age that is pleasing to both self and others." (p. 279). In the Encyclopedia of Aging, Palmore (1995) says that a comprehensive definition of successful aging "would combine survival (longevity), health (lack of disability), and life satisfaction (happiness)." (p. 914). Additionally, some gerontologists have discussed similar issues using different terms such as "adjustment" or "adaptation" to aging.

The shifting meanings of successful aging have paralleled changes in prevailing theories of social and psychological aspects of aging, because ideas of what constitutes successful aging are implicitly contained in each theory. One of the first theories of aging, Cumming and Henry's "disengagement theory" (1961), proposed that in the normal course of aging, people gradually withdrew or disengaged from social roles as a natural response to lessened capabilities and diminished interest, and to societal disincentives for participation. In this model, the successfully aging person willingly retires from work or family life and contentedly takes to a rocking chair, or pursues other solitary, passive activities while preparing for death. Although the theory seems dated today, it made sense in an era characterized by shorter life expectancy, earlier onset of disability, physically demanding work roles, mandatory retirement and few organized activities for older adults. To social scientists in the 1960s, what was typical or common among older people may have shaped the perception of what was optimal or possible.

A second major theory of aging, referred to as "activity theory", proposed that people age most successfully when they participate in a full round of daily activities, that is, keep busy (Lemon, Bengtson & Peterson (1972). This theory seemed to explain the surge of volunteerism and senior activism in the 1960s and 1970s and may have been partly responsible for public policies which underwrote the development of senior centers and other recreational facilities in that period. Today, the theory has been discarded by gerontologists who view it as too narrow in its implied advocacy of one particular lifestyle. Empirical research has demonstrated the heterogeneity of older people, including many people who prefer less structured lives or do not have the health or means to pursue a full schedule of activities. Nevertheless, activity is widely touted by older adults themselves as the key to successful aging, so much so that gerontologists have dubbed this philosophy "the busy ethic" (Ekerdt, 1986).

A third theory of aging which has been viewed with much favor in recent years is called "continuity theory" (Atchley, 1972). This theory proposes that the people who age most successfully are those who carry forward the habits, preferences, lifestyles and relationships from midlife into late life. This theory has gained considerable support from the results of major longitudinal research studies which have shown that variables measured in midlife are strong predictors of outcomes in later life, and that many psychological and social characteristics are stable across the lifespan. For most people, late life does not represent a radical break with the past; changes often occur gradually and sometimes imperceptibly. Most people ride over or navigate around the bumps and potholes of later life using well-practiced coping skills acquired earlier in life.

Concurrent with these developments in social gerontology, theorists and researchers in the biomedical arena have also been proposing and testing models of successful aging. Until the 1980s, many researchers defined successful aging in terms of length of life. Some studied factors associated with the extraordinarily long lives of some people in remote areas of the world. Others did laboratory experiments exploring the possibilities of lengthening the human life span by carefully controlling such factors as dietary intake. More recently, considerable attention has been given to investigating ways to delay the onset of disability, thereby lengthening the number of years of "active life expectancy", that is, the number of years of life spent without significant disease or disability (Fries & Crapo, 1981; American Federation for Aging Research & the Alliance for Aging Research, 1995). This trend demonstrates the realization among biomedical researchers that quality of life is as important as quantity of life, or is at least a necessary part of successful aging.

Emerging Trends

Another and perhaps more surprising development has been the emergence of schemas for successful aging for those people who experience significant hardship in later life. Although discussion of these issues has occurred for decades among the many care providers who work to enhance the well-being of impaired and institutionalized persons, most gerontologists have neglected these populations in their theories and models of successful aging. Indeed, in a provocative and important article on "aging well", Austin (1991) reminded the gerontological community not to forget those who cannot age well because of social factors over the life course (e.g., poverty, rural residence, poor nutrition, substandard housing, limited educational opportunities, abuse or catastrophic losses) that reduce life chances and limit access to an "aging well lifestyle".

Diverging from works of the 1980s that emphasize "maximizing independence" or "enhancing autonomy" in the frail elderly, Lustbader (1991) described the possibilities for finding satisfaction and meaning even in a state of dependency, including moments of vivid aliveness, true intimacy between family members, and spiritual revival. A recent book on enhancing the spiritual well-being of people with Alzheimer's disease (Gwyther, 1995) also addresses some of the same issues in a severely impaired population.

Taken together, these emerging trends suggest that a two-tiered approach to defining the successful aging (one for healthy older adults and one for the frail) more accurately fits the empirical realities of aging. And, as the older population becomes increasingly diverse, the concept of successful aging may become even more difficult to define without expanding the number of models. One solution may be to return to an early (and continuing) theme in research on successful aging, that is, that successful aging is in the eye of the beholder. In this framework, successful aging is measured with indicators of subjective well-being such as life satisfaction, happiness, morale, contentment, perceived quality of life or other related measures of negativity such as depression, anxiety, etc. New efforts in the measurement of quality of life (Guyatt and Cook, 1994) and personal goals (Bearon et al., 1994), and innovative qualitative studies on older adult perceptions of life satisfaction and successful aging (Fisher, 1992) suggest that there may be new and fruitful avenues for capturing and comparing individualized outcomes and developing a more variegated view of successful aging.

Written by: Lucille B. Bearon, PhD, Adult Development & Aging Specialist, North Carolina Cooperative Extension Service and Assistant Professor, Department of Family and Consumer Sciences, North Carolina State University, Raleigh, North Carolina, lbearon@amaroq.ces.ncsu.edu