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and the activities of individuals. Sociologists extended more general theoretical
frameworks already used widely in the discipline, such as functionalism and
symbolic interactionism, as foundations for development of what they hoped
would be general theories of aging. Individuals were the unit of analysis, predic-
tion centered around optimal and dysfunctional adjustment to old age (Hen-
dricks & Achenbaum, 1999), and social factors were taken for granted rather than
analyzed in the models (Hendricks, 1992).
Empirically testing the competing micro-level theories created something of a
growth industry in a spate of studies of aging individuals in the 1960s and 1970s;
disparate findings and rival theoretical frameworks encouraged more careful
theory building and launched increasingly sophisticated studies. As interest in
social gerontology grew, accompanied by a growing awareness of the demo-
graphic phenomenon of aging populations and public policies geared toward
meeting the needs of the elderly, sociologists recognized that exclusively micro-
level theories offered an incomplete picture of social aging. They expanded their
repertoire to develop meso-level (or middle-range) theories that explored the
linkages between individuals and society, and macro-level theories that specified
the structural relationships between society and individuals in the context of the
changing age structure of national populations. The three analytic levels of analy-
sis provided the foundations for the sociological study of aging, but more re-
cently, critical gerontology and life course studies have shown potential for
specifying linkages across levels of analysis. These overlapping critical and life
course theoretical orientations, combined with new methodological techniques
and the increasing availability of rich longitudinal data sets, show promise for
the continued centrality of sociological contributions in the study of aging (e.g.,
O’Rand & Campbell, 1999).
As discussed earlier, one useful way to think about theories of aging is to clas-
sify them by what each takes as its central puzzle: the subject of research interest
(individuals, relationships, institutions, or society) and the focus of each theory.
For example, micro-level theories of aging, such as disengagement theory, activity
theory, and continuity theory, center on the individual as the subject of interest
and explore the psychosocial and sociological factors that improve understanding
of variations in outcome for elderly individuals. Micro-level theories owe much to
theories of psychological development (see Chapters 2 and 3) for their conceptual
consistency and signal one family of sociological theories that bridge disciplines.
Meso-level theoretical approaches, such as subculture theory and exchange
theory, incorporate concepts that specify the relationships between individu-
als and social systems. For example, formation of subcultural groups of old
people can occur both through positive (e.g., similar interests, friendships)
and negative (e.g., exclusion from social participation) social processes. In con-
trast, exchange theory emphasizes relationships modeled after microeconomic
exchanges, characterizing the experiences and behaviors of aging individuals
as efforts to maximize their rewards and minimize costs. Meso-level theories
are, in one sense, bridging theories within the discipline (see Marshall, 1999),
encompassing at least some of the core conceptual categories of both micro-
and macro-level theories.
From a more structural vantage point, sociologists use macro-level theories to
understand aging at the societal level. Early macro-level studies of aging in-
cluded modernization theory and age stratification theory. As another manifes-