and self-efficiency in some older individuals who are deficient in these qualities have had dramatic effects on function and health.
Research in the social and behavioral sciences has emphasized that aging is an interactive and lifelong process. This view also has provoked interest in the associations among biological differences, behavior and psychosocial processes, and alterations in physiological systems in health and disease.
The potential of the aging process to respond to modification provides a unique opportunity for future research. Individuals arrive at the end of life by quite different socially determined, as well as biologically determined, routes. Differentiation in older adults provides some of the best evidence for the modifiability of aging processes and the experience of aging. Differentiation refers to variability in aging, both within and across societies. Studies have found that behavioral capacities are multidirectional over the adult life course: some remain stable, and others decline or improve. Because individuals adjust to biological decline in aging, behavioral decline often is minimal.
Aspects of differentiation in elderly persons also involve variations in individual and cohort lifestyles, risks of illness and dependency, and functional capacity. Cultural and psychological processes influence the aging process in varied and consequential ways. Most studies documenting this influence have focused on reducing agerelated decrements in health. Research is needed to specify the broader areas and limits of the modifiability of aging, emphasizing the enhancement of existing skills and the potential for learning new skills in later life.
Another major perspective in social and behavioral research focuses on the interaction between person and environment. Specific sociocultural contexts influence the aging process differently in specific individuals. Study of these contexts should include how aging differs across societies and across cultural, racial, and ethnic groups; how aging is influenced by differences in work place, treatment environment, living arrangements, and other material and social supports; and how individual capacity and social milieu affect behavior and health outcome.
Three research priorities emerge from these themes.
Investigation of the basic social and psychological processes of aging, including specific mechanisms underlying the interrelation