aging and the life course, theories of 75

Riley and her colleagues (e.g., Riley et al.
1994) proposed a theory of structural lag in
the 1990s, which argued that changing demo
graphic patterns associated with increased
active life expectancy and the delayed onset
of disability (among other factors) have made
age based public policies associated with work
and retirement obsolete and counterproductive
for society. However, even more compelling
was their argument that the life course is shift
ing in nearly every respect away from age dif
ferentiation to age integration. Figure 1 is an
expanded version of the Riley age integration
model of the new life course. It portrays the
shift from an age differentiated conception of
the life course, in which social statuses in
youth, middle age, and old age are strictly
separated, to an age integrated life course over
which statuses and status transitions can recur
and co occur across ages and domains of life.
Work and parenthood can occur early in life;
education may continue later in life; parent
hood may also extend to later life and be
accompanied by family roles associated with
assisting elderly parents; remarriage and new
family formation can continue well into older
ages. In addition, changes occurring in one
domain of life at any time (e.g., divorce in
middle age) can trigger changes in other
domains of life (e.g., returning to school,
entering the labor force, a decline in mental
health). The figure captures the dynamics
among the three principles of the life course
perspective noted earlier: age stratification,
heterogeneity, and demographic pressure.

These basic elements of the life course per
spective are products of the convergence of
several sociological traditions over the last
three decades. Since Ryders classic essay
(1965), social demography has steadily con
tributed to the life course perspective through
the development of dynamic models of life
transitions such as marriage, fertility, and
employment and their interdependence across
historical contexts (e.g., Oppenheimer et al.
1997). Status attainment theory has moved in
the same direction by steadily elaborating the
relationship between social origins and later life

Figure 1 Expanded age integration model of the life course.