Biologists have emphasized the inevitability and unidirectionality of decline (Rockstein and Sussman, 1979; Finch and Schneider, 1985). Psychologists, however, have found that some behavioral capacities are multidirectional: some improve over the life course, some remain stable, and others decline (Woodruff-Pak, 1988). Further, because individuals are adaptive in their behavioral adjustment to biological decline in aging, behavioral decline often is minimal. Moreover, understanding the range of limits of physiological decline and its consequence for behavior is an important priority for future research.
One of the most exciting frontiers involves the examination of the interaction among behavior, central nervous system structure and function, and neuroendocrines and other hormonal factors. Examples include investigation of the relationship between memory function and such central nervous system structures as the hippocampus and cerebellum (Berger et al., 1986) and research on stress-related environmental, psychological, and hormonal factors that lead to anatomic changes in the brain (see cerebral atrophy under extreme stress: Jensen et al., 1982; Finch, 1987). Although extensive descriptive literature exists on both physiological and psychological changes in advancing age, only limited information is available on specific behavioral correlates of specific biological changes. Data on specific interactions between biological and psychosocial factors are even more sparse. It is suspected, for example, that adverse changes in the synchrony between the autonomic and central nervous systems in advancing age may affect intellectual performance, particularly in jobs or tasks requiring complex decision making.
Despite the recognition that the major health problems of older people are chronic, little attention has been paid to behavioral and social interventions to reduce excessive disability and provide new treatment and management strategies. Some key issues for researchers include rehabilitative strategies to maintain or restore function, treatment of the social or emotional barriers to rehabilitation, and compliance with medical regimens. A variety of behavioral interventions—biofeedback in hypertension, for example—appear promising (Zarit, in press). Behavioral interventions also can be used to enhance performance of older people (Rodin, 1986).
The movement from work to retirement is one of the most important life-course decisions facing middle-aged and older workers. It has significant public policy implications, deriving from federal regulations, personnel policies, and decisions of workers. New social and economic surveys need to link business characteristics, such as pension plans and retiree health insurance, with individual career and retirement decisions. It is important to examine the age-