Equally important is clarification of mechanisms of recovery from and resistance to adversity. It is important to give equal consideration to positive aspects of people's lives and particularly to accumulation of advantage. The components leading to cumulative advantage may come in the form of starting resources (e.g., growing up in an intact family), personal capacities and abilities (e.g., intelligence, coping strategies), positive behavioral practices (e.g., exercise, proper diet), the realization of expected life transitions (e.g., job promotions, marriage), or having positive evaluations of one's life (e.g., job satisfaction, marital quality, and positive personal relationships with children, siblings, and friends).
Simultaneous consideration of cumulative adversity and advantage as they pertain to understanding health outcomes, including resilience, has been the theme of several recent investigations (Ryff et al., 1998). In understanding pathways into and recovery from episodes of depression, for example, the cumulative processes of both negative and positive valence must be identified (Singer et al., 1998). The basic point is that pathways to diverse health outcomes depend on an interplay of both positive and negative experiences across multiple life domains. (See also Chapter 3.)
At the level of physiology, an indicator of the long-term physiological response to stress conceptualized as allostatic load (McEwen, 1998; McEwen and Stellar, 1993) provides the important beginnings of a bridge between measures of cumulative psychosocial adversity relative to advantage and their biological signature. The conceptualization and measurement of this construct are described in detail in Chapter 2. Representing an index of risk across multiple physiological systems, allostatic load has been found to predict later-life incident cardiovascular disease, decline in physical and cognitive functioning, and mortality (Seeman et al., 1997). Allostatic load also represents a physiological signature of cumulative adversity relative to advantage in the domains of economic resources and social relationship (Singer and Ryff, 1999). An important research topic for the future is further investigation of linkages between cumulative SES-related adversity and cumulative physiological risk, represented by allostatic load, as well as assessment of psychosocial and behavioral factors that can offset the accumulation of such load.
There are few longitudinal data sets that both cover long stretches of lives (e.g., 35 plus years) and include both psychosocial and physiological risk factors as well as health outcomes. National surveys of the birth cohorts of 1946 and 1958 in England (Power and Matthews, 1997; Wadsworth and Kuh, 1997) represent valuable sources of psychosocial