Emerging Trends in The Social and Behavioral Sciences

Aging and the Life Course

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Aging and the Life Course

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Aging and the Life Course
ANGELA M. O’RAND

Abstract
This essay reviews major elements of aging and life course research, its foundations, frontiers, and research challenges. This research examines how human lives
are organized and manifested across the life span in different environments. The first
foundation of life course research is the historical observation of the institutionalization of the life course; that is, how it became standardized in industrialized contexts
through the operation of work, family and state institutions and how it is increasingly
destandardized in the new global economy. The second foundation is the examination of the life course as a process that is manifold and cumulative: manifold because
it consists of intertwining roles and events over time and cumulative because it consists of sequentially contingent transitions and path-dependent processes. The third
foundation is the recognition of the formative and enduring impact of exposures to
severe life conditions or major sustained macro events such as wars or disasters. The
stress process is the fourth foundation that addresses how stresses over the life course
shape its trajectory. Finally, cognition and emotion over the life span serve as a foundation for the major psychological experience of aging. Three frontiers of life course
research are highlighted: the individualization of the life course and the devolution
of risk; cumulative advantage and cumulative disadvantage as major processes of life
course inequalities; and biological processes and the life course. The essay ends with
consideration of life course data and methods and the challenges of interdisciplinary
research.

INTRODUCTION
The question of how human lives are organized and manifested over the
life span has occupied scholars from many disciplines including gerontology, demography, psychology, sociology, history and other social science
specialties, the humanities, and some biological sciences. These disciplines
have focused on different aspects of aging or the successive phases of the
life course, which constitutes a manifold process comprised of interwoven
components that are distinct but interdependent in complex ways over
time. As such, human biographies are products of the multiplex interactions
among biological, psychological, social-structural, and cultural-historical
factors as individuals age from birth to death. Biological aging formatively
Emerging Trends in the Social and Behavioral Sciences. Edited by Robert Scott and Stephen Kosslyn.
© 2015 John Wiley & Sons, Inc. ISBN 978-1-118-90077-2.

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proceeds toward the limit of human life spans, but is constrained in the
process by psychosocial differences, opportunity structures and life chances,
cultural schema, and historical conditions that produce differences in human
lives across and within age-groups. These constraints differentiate the life
courses of human cohorts in ways that result in cumulative disparities in
psychological and physical health and mortality, socioeconomic inequalities
spanning childhood and adulthood, and diverse psychosocial cognitions
and identities, among other differences.
The life course framework has emerged over the past six decades as a
product of the convergence of several traditions in US and European social
sciences concerned with common or related problems. The doubling of
life expectancy around the world over the past 200 years has established
aging as a central existential phenomenon that drives historical and social
change and which, in turn, is a result of social forces related to the control
of diseases of various kinds in different periods, economic development
and global restructuring, and social institutions regulating normative life
transitions, life scripts, social inequalities, and life-and-death processes.
At the population level, aging is defined by the demographic transition
from high mortality and high fertility to steeply declining rates of both in
relationship to differential economic development across countries over
this long period. The demographic transition has been accompanied in
recent decades by an epidemiologic transition in which chronic disease has
superseded infectious disease as the dominant cause of poor health or death
in the most advanced countries where population aging has reached its
highest levels.
At the individual and cohort levels, the aging experience is defined by life
course processes that reflect the interactions among biological, institutional,
economic, historical, and psychosocial factors. Cohorts consist of individuals
who encounter history at the same ages together, but who have differential
experiences that result from these encounters.
This essay will emphasize aging at the individual and cohort levels of
analysis, although aging at the population level provides a historical context
that has independent effects on the individual life course and the aggregate
experiences of cohorts, especially on social patterns related to differential
employment opportunities across ages and retirement policies for the old.
The confluence of foundational research from several traditions has identified five general factors that shape and condition the length of and quality
of life for individuals and cohorts: the institutionalization of the life course;
the manifold, cumulative life course; fundamental causes and situational
imperatives; the stress process; and cognition and emotion over the life span.
The identification of these factors has propelled life course research and

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generated several current research fronts or cutting-edge research agendas
that will be identified later in this essay.
FOUNDATIONAL RESEARCH
INSTITUTIONALIZATION OF THE LIFE COURSE
The major foundation of aging and life course research focuses on the institutional and cultural origins, and ongoing construction and reconstruction,
of the phases of life defined by age-related roles, institutional policies, and
long-lived traditions. The institutional tradition identifies social regularities
in the aging process and their bases in social structure and culture. It maps
the domains of life, including family, education, work, health, citizenship,
and leisure, among others, defined by institutions, and investigates their synchronization or interconnectedness over time. It also examines the processes
of inclusion and exclusion that allocate populations across institutional sectors and into status groups by age, gender, race/ethnicity, citizenship, nativity, and other socially meaningful categories with differential social obligations and rights with age.
The tripartite life course has been described by Martin Kohli as the dominant standardized form in industrial (or work) societies with age-related
roles organized for the young around education, for adults around work
and family, and for the old around retirement. State, market, civic, and other
institutions complement each other to construct and reinforce this configuration. Educational systems, age laws protecting youth from social risks (e.g.,
child labor, alcohol, and driving), and auxiliary civic programs developed
to support children’s development and socialization, among other institutions, define the first tripartite phase. The adult phase is also constructed by
legal and traditional systems regulating marriage, parenthood, the employment sector (employers and workers), social protections of individuals and
families, civil activities, and social behaviors. Finally, retirement institutions
define the last phase, including its timing, social and economic entitlements,
and cultural status.
Much research has focused on major transitions in the tripartite life course,
particularly the transition to adulthood and the transition to retirement. The
transition to adulthood is observed as a demographically dense sequence
of multiple transitions from adolescence to adulthood that signify movement towards social independence from the family of origin. These transitions include finishing or leaving school, leaving home, entering the military,
starting work, marriage, and pregnancy and childbirth. The sequencing of
these transitions was normatively regulated for several generations, but is

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undergoing change across countries. Demographic researchers have characterized this change as “the second demographic transition,” which includes
remaining in education until later ages, delaying marriage or never marrying, cohabitation, and childbirth outside of marriage and childlessness.
Changing gender roles are implicated in this transition as women complete
higher education at higher rates and enter and stay in the labor market during
longer periods in their lives. One welfare state theorist, Gösta Esping Anderson, refers to this process as defamilization.
The transition to retirement includes the exit from income from paid work
to income from a pension. Retirement institutions have varied across countries in their regulation of the age(s) of retirement of different subgroups;
however, the fiscal pressures of population aging in advanced countries,
where the ratios of workers to retirees have declined, have impelled efforts
to extend the retirement age to later years. Retirement institutions have also
varied in the mix of social, occupational, and private sources of pensions.
Social pensions are usually based on rules of entitlement not necessarily
connected to employment. Countries with more liberal welfare institutions
(e.g., USA, and UK) have historically favored occupational and private
sources of pension income, while social democratic (e.g., Norway, and Sweden) and corporatist governments (e.g., Germany, and The Netherlands),
respectively, have provided higher ratios of social benefits to retirees. However, population aging and global macroeconomic forces have encouraged
the latter to shift in the direction of occupational and private savings regimes
similar to liberal states to offset the rising costs of social pension systems that
are less sustainable than in the past. Proposals for gender-neutral benefit
policies and for later ages of normal retirement are spreading throughout
the advanced and developing world.
THE MANIFOLD, CUMULATIVE LIFE COURSE
The second foundation of life course research focuses on the more finely
gauged temporal dynamics of aging beyond the simpler phasic approach
summarized above. In this line of research the life course is examined as a
manifold phenomenon of intertwining cumulative processes. The two major
components of this research include the ideas that (i) lives are lived simultaneously across multiple domains (education, work, family, health) where
experiences in co-occurring roles or with co-occurring events are mutually
influential or interdependent and (ii) lives are path-dependent and comprised of chains of sequentially contingent transitions. The first component
emphasizes the manifold structure of lives over time. It addresses the phenomena that individuals have multiple “careers” as they age—educational
careers, family careers, work careers, health histories, and so on—that are

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mutually influential. Extended educational careers tend to delay work,
marriage and childbearing, that early exits from education are associated
with earlier childbearing for women and earlier work for men. Loss of a
job can precipitate returning to schooling or a decline in mental health. The
onset of a physical disability increases the likelihood of loss of employment
and/or exposure to poverty. Long-term unemployment increases the onset
of cardiovascular diseases, and so on.
This component also includes the idea of “linked lives” based on the work
of Glen H. Elder, Jr. and his colleagues over several decades. The manifold
life courses of related individuals influence each other. Hence, the loss of a job
by a working father can have an impact on the course of his children’s lives.
Alternatively, the early parenthood of a single mother significantly predicts
the repetition of this pattern in the next generation.
The second component emphasizes the cumulative processes that lead
to stratification and individualization in aging cohorts. Later statuses and
events in the life course are contingent on earlier statuses and events.
Sequential contingency reflects aging as a social selection process across
individuals, with increasing intra-individual continuities as they age.
However, the temporal characteristics of sequential contingency are complex. First, the order and timing of some transitions in the life course are
consequential for later life outcomes, especially if order or timing has strong
normative underpinnings or institutional requisites. For example, adolescent childbirth outside of marriage is associated with the lower likelihood
of high school completion and higher risks for poverty later. Second, the
temporal proximity of earlier and later transitions can have quite different
effects. The loss of a job that is rapidly replaced by a new one increases the
probability of future job and income stability. Alternatively, the duration of
unemployment negatively affects reemployment and increases the risk for
poverty.
Sequential contingency generates differentiation in aging cohorts as individual lives become increasingly distinct. Glen H. Elder, Jr has identified the
“accentuation principle” in life course research that observes that individuals’ earlier behaviors and preferences are not only continued but often amplified across succeeding transitions. The famous Bennington Study follow-up
by Duane F. Alwin, Ronald L. Cohen, and Theodore M. Newcomb demonstrates this principle in the longitudinal study of women’s political attitudes
over time and their selections of spouses with similar attitudes.
FUNDAMENTAL CAUSES AND SITUATIONAL IMPERATIVES
In countries and regions with weaker institutional protections against life
course risks such as poverty or illness inequality is pervasive in aging

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cohorts, beginning with childhood. Research on numerous manifest life
course outcomes, including health disparities and economic inequalities,
repeatedly demonstrates the enduring impacts of childhood conditions and
opportunity structures for young adults on health, mortality and economic
well-being in later life. Early exposures to poverty and poor health exert a
social gravity on the later life course through observable processes of exclusion from or limited access to resources such as education. Fundamental
cause theory argues further that much of the effect of early poverty and
poor health is latent and not readily observable until later in life. The long
latency of these exposures exists cognitively and physiologically, masking
scars or hidden injuries that are nevertheless consequential. As such, this
body of work is interested in the question of how adversity “gets under
the skin.” Further, the theory argues that statistical mediation of the effects
on childhood adversity by intervening variables does not diminish the
fundamental and pervasive impact of these conditions throughout life.
In a similar vein, Glen H. Elder, Jr argues that negatively disruptive life
events such as job loss as well as severe and sustained large-scale events
such as economic depressions and wars have enduring manifest and latent
impacts on lives. These situational imperatives can redirect lives or amplify
earlier behaviors and perceptions that have developed over the life course.
THE STRESS PROCESS
The stress process is a widely used model in medical sociology developed
by Leonard I. Pearlin that focuses on individuals’ responses to primary life
stressors (traumatic life events, hardships, challenges) and secondary stressors (role strain and diminished self-concept) that are conditional on social,
economic and personal resources and prior exposures to stressors. The stress
process is cumulative and can be initiated by traumatic experiences and cascade into serial episodes and encounters with new stressors over the life
course. The chief outcome of interest is mental health and its effects on physical health and the general well-being of aging populations and those who
care for them. Successful coping mechanisms and access to social supports
are chief mediators in the stress process.
COGNITION AND EMOTION OVER THE LIFE SPAN
Cognitive aging has been observed for decades by researchers and aging
individuals alike. What has been established in the research is that cognition
is multidimensional; declines in measured cognitive function are significant
and manifestations of a more general neurological decline; and they begin
early in adulthood. Variability in cognition over the life span is traceable

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to childhood conditions and their impact on cognitive and socioemotional
development. At the population level, patterns of cognitive decline appear
to be constant across succeeding twentieth-century cohorts, a counterintuitive finding largely attributable to “survival effects” or the ability of lower
cognitive functioning individuals to survive in more recent cohorts as a result
of economic and technological development. The chief conundrum is to separate age effects from the effects of other (sometimes unmeasured) variables,
especially in cross-sectional research.
Cognitive functioning and socioemotional development are associated
over the life course, with the latter strongly implicated in motivation.
Laura Carstensen’s socioemotional selectivity theory argues that over
the life course time horizons shrink and aging individuals are motivated
by different goals than younger individuals. Younger individuals have
longer time horizons and are motivated by knowledge-related or rational
goals associated with developing skills, career aspirations, and instrumental relationships. Older individuals have shorter time horizons and are
motivated more by emotion-related goals associated with the quality of
present-centered social relationships and interactions. The latter age group
also prefers positive over negative information in their observations and
recollections.
CUTTING-EDGE RESEARCH
INDIVIDUALIZATION OF THE LIFE COURSE AND THE DEVOLUTION OF RISK
Globalization processes characterized chiefly by the ascendance of market
and financial practices that generate economic uncertainties are eroding
the twentieth-century state, employment, and family institutions that
constructed the standardized tripartite life course. Employment security has
declined across economic sectors (first in manufacturing, then in service and
other sectors) as market enterprises engaged in price competition seek to
reduce labor costs and increase shareholder returns; advocate deregulation,
privatization and liberalization policies; depend on information and communication technologies for management and information diffusion; and
are increasingly vulnerable to random shocks with distal origins. Arguably,
employment security has been the fulcrum of the tripartite life course by
providing predictable and protected economic resources for workers and
their families, often through corporatist arrangements among employers,
unions, and governments. These resources accompanied by publicly supported educational, health, and retirement policies have anchored the life
course.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Research over the past decade reveals the strongest emergence of globalization forces that make employment security highly problematic. These forces
also have centrifugal impact on the life course since the erosion of social institutions protecting against life course risks leads to the devolution of risk. The
devolution of risk refers to the shift of responsibility for the management of
life course risks to individuals and their families and away from collective
institutions associated with state policies and earlier employment institutions. Shared resources and shared entitlements are disappearing, albeit more
quickly in more liberal regimes than others.
Research reveals that the shift transcends the employment sector to include
educational institutions, which are becoming more decentralized and privatized in liberal states, and family institutions, which are vulnerable to the
centrifugal effects of economic insecurity and the loss of welfare protections.
In the case of the former, education has become less equally accessible across
countries. Family income is affecting educational life chances. In the case of
the latter, family dynamics related to everything from fertility to divorce and
children’s educational opportunities are sensitive to macroeconomic changes
that are not buffered by social protections.
The convergence of globalization with population aging has had particular
impact on the life course, especially in its major transition phases to adulthood and to retirement. Many studies of these transition periods across countries demonstrate growing insecurity for young and older workers alike. The
flexCAREER Project funded by the German Research Foundation and led by
Hans-Peter Blossfeld has compared the changing features of these transitions
across OECD countries. The key concept in this project is the spread of flexible employment (also referred to as precarious work by Arne Kalleberg) characterized by short-term, part-time, and contingent work that is more likely
to be encountered by new labor market entrants, women and racial/ethnic
minorities. This work is characterized by low wages, nonstandard hours, and
little to no benefits. The duration of this exposure in employment careers is
consequential for later employment security. Random shocks such as recessions affect this labor market sector first. Accordingly, research on the transition to adulthood across countries finds observable delays among the young
in entering fulltime stable employment that, in turn, has delayed parental
home-leaving, fertility and family formation in this group. What remains
unclear is the extent to which these patterns are long- or short-lived for these
younger cohorts.
Mid-career and older workers are typically more secure in employment as
a result of their cumulative careers. Indeed, many advanced countries implemented early retirement policies in the twentieth century in order relieve
national labor markets. In the current context, the challenges are different
and contradictory. Early retirement policies present new challenges as life

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expectancy increases in the retired population and the ratio of retirees to
younger workers increases. Demographic and policy research over the past
decade reveals the efforts of different countries to diminish the burden of
pension and related costs through legislation for later eligibility for retirement benefits and incentives for the privatization of retirement savings for
younger cohorts. Although pension politics vary across countries given their
political, economic and cultural histories, the shift is clearly towards occupational pensions and private savings regimes, especially but not exclusively
among liberal market states.
Still even mid-career and older workers are being affected by random
shocks and contracting employment opportunities across sectors. Normal
volatility in stock markets has typically had less effect on older workers’
continued employment than extended recessions with sustained high
unemployment. The latter increases the rate and duration of unemployment
among mature workers, decreases the likelihood of reemployment (especially with increased duration of unemployment), increases the likelihood
of flexible employment, and leads to intermittent work careers (careers that
mix part-time and full-time employment with unemployment, underemployment, and disability) that can last for many years before retirement
eligibility.
Research is demonstrating that this stratification of the labor force increases
income inequality in aging cohorts, especially in societies with less regulated economies. The devolution of risk promotes what some researchers
refer to as a free-agent mentality, or an isolated market participant identity
of individualization that challenges earlier notions of class, occupation or
union membership as the strong basis of economic identity. The free agent
mentality also introduces variability in the choices made by individuals that
range from school choices for children, to family migration decisions, to the
retirement transitions. As such, diverse temporal pathways across the transition to adulthood and retirement have been observed. The accumulation of
highly individualized decisions increases the likelihood of increased inequality, especially in the absence of equalizing institutions.
CUMULATIVE ADVANTAGE/DISADVANTAGE
After controlling for the impact of equalizing institutions, the individual
mechanisms whereby economic and health or mortality inequalities in
aging cohorts emerge are the foci of considerable research across countries.
Overall, research across countries and cohorts demonstrates two general
patterns: that inequality pervades the life course, especially in liberal welfare
contexts, and that it is generally cumulative, with successive statuses significantly predicted by earlier statuses. These patterns are labeled as cumulative

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advantage and cumulative disadvantage. Research is uncovering three
principal loci of these inequalities—inter-cohort variations, childhood
conditions, and educational attainment—although some disagreements
persist in the literature on the relative priority of social selection versus
social causation in the distribution of economic and health disparities.
COHORT VARIATIONS
Recent research has made much ground in disentangling the effects of age,
period and cohort in longitudinal and pooled cross-sectional data. These
innovations have assisted in determining whether social (sex, class, and
race) disparities in outcomes such as health and mortality follow similar
cumulative patterns across birth cohorts. While cumulative patterns are
identified across cohorts, cohort-related changes have also been uncovered:
trajectories of different health conditions (e.g., heart attacks) vary across
cohorts; social inequalities exist in the levels of some health conditions
but not in the growth rates of health conditions; and the widths of social
disparities in health vary across cohorts.
Similar cohort variations have been observed in education. Generally, successive cohorts have increased levels of educational attainment in a nonlinear pattern revealing a slowing of growth. A major cohort-related change is
the change in educational attainment by gender, with women in the most
recent cohorts in advanced countries completing secondary and higher education at higher rates than men. Research suggests that one explanation is that
women’s market roles require more educational credentialing than men’s.
The full explanation has not been uncovered.
CHILDHOOD CONDITIONS
The availability of longitudinal datasets with baseline observations in
childhood and adolescent samples and reliable retrospective survey items
about childhood health and economic adversity have energized scholarship
on the impact of childhood on later life well-being. This research is adding
greater specificity and complexity to the more general fundamental cause
and situational imperative traditions outlined above. Childhood conditions
are associated with later life outcomes through processes of accentuation,
amplification, and mediation depending on the outcome of interest (e.g.,
mortality) and on the intervening life conditions studied (e.g., educational
attainment, employment stability, and marital history) and the temporal properties (trajectories) of these intervening conditions (e.g., timing,
sequence, and duration).

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BIOLOGICAL PROCESSES AND THE LIFE COURSE
Once an unorthodox and largely infeasible line of research in the life course,
the examination of biological processes involved with the life course has
emerged as a frontier. This is driven by some long-standing and some
recently emergent research concerns. A long-standing question in the
demography of the life course regards the health-survival paradox in gender
life expectancy. Researchers have been challenged to explain the female
advantage in survival in spite of women’s poorer health over the life span.
Observable gender-related patterns of health behaviors and social relationships have been implicated in this paradox: men engage in more risky
health behaviors and women maintain more salient and supportive social
ties. However, underlying biological processes have been suspected to be
interdependent with these more readily observable patterns. Similarly, the
variable onset and courses of mental and physical diseases and disabilities
have been tied to observable behaviors, but the contributions of biological
processes to these trajectories have only recently been implicated in these
life course processes. The actual mechanisms of interdependence have only
begun to be specified.
Some longitudinal studies have thus turned to collecting biomarker data
from study participants to study biological markers of physiological and
endocrinological responses to environmentally mediated experiences such
as stress (cortisol) that bear upon the life course. Neuroscience methods
(e.g., fMRA scans) are also increasingly integrated into social psychological
processes of aging including cognitive decline, depression and other mental
health conditions. Finally, heritability and gene–environment interactions
have become the newest candidates for studying the life course from
childhood to old age. Twin studies were the initial method for conducting
experimental and panel research on heritability and gene–environment
interactions in intellectual development and social behaviors. In addition,
recently the life course literature has grown substantially with studies of heritability in such behaviors as alcoholism, church attendance, coping styles,
educational attainment, impulsivity, self-esteem, among other measureable
behaviors with life course implications. Following twin studies, target gene
studies [which examine specific genes associated with diseases such as
Alzheimer’s (APOE) or Parkinson (GBA)] have proliferated to improve
prediction of the risks for and onset of diseases associated with aging.
Similarly, studies focused on DNA sequence variations between individuals
(single-nucleotides polymorphisms—SNPs) use technologies similar to
DNA fingerprinting to look for multiple genetic variations correlated with
observable behaviors and health conditions over the life course. Questions
of feasibility and reliability dominate this research, but this frontier is

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perhaps the most interdisciplinary growing tip of life course research in the
twenty-first century.
KEY ISSUES FOR FUTURE RESEARCH
STEADFAST MAINTENANCE OF COMPARABLE LONGITUDINAL STUDIES
Although an important place remains in life course research for case studies
and qualitative examinations, frontier research strongly depends on longitudinal data and analytical methods that capture dynamic processes. The life
course consists of events, transitions, and trajectories and sequences that,
when monitored as close as possible in “real” time, permit the tracking of
lives being lived through history. Longitudinal data also can incorporate
causal factors, from retrospective accounts of the earlier biography and
also in “real” time as lives proceed across the multiple domains of family,
education, work, health, leisure, and so on. Hence, the manifold, cumulative
life course becomes observable.
Since the late 1960s, in the United States, Britain, and Europe, longitudinal databases for life course research have proliferated. Today publicly
available databases for aging-related secondary analyses in this area are
available in multiple countries. The US National Institutes of Health
maintains updated listings of and links to many of these data sources (see
http://www.nia.nih.gov/research/dbsr/publicly-available-datasets).
Notably, over the past two decades efforts towards the development and
maintenance of comparable databases across countries have succeeded.
Following the US Health and Retirement Study (HRS) initiated in 1992
and continuing biennially to the present (http://hrsonline.isr.umich.edu),
longitudinal databases using identical and comparable survey items have
been initiated in several countries:
SHARE in Continental Europe and Israel (http://www.share-project.org)
ELSA in England (http://www.ifs.org.uk/elsa/)
KLoSA in South Korea (excl Jeju) (http://klosa.re.kr/KLOSA/default.asp)
MHAS in Mexico (http://www.mhas.pop.upenn.edu/English/home.htm)
All of these databases follow mature samples over the age of 45 at the
first wave. Other national databases developed more recently include: the
Japanese Health and Retirement Study (JHRS) with first wave in 2007;
The Chinese Health and Retirement Longitudinal Survey (CHARLS) with
first wave in 2010; the Longitudinal Aging Study in India (LASI) with first
wave in 2010 or 2011; and the WHO Study of Global Ageing and Adult
Health (SAGE). Many of these surveys include collection of biomarker data

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and linkages to health and earnings records that permit a triangulation of
data and the examination of biological and social processes as well as the
reconstruction of past work and health histories.
Databases with more age-heterogeneous and younger samples are also
useful for longitudinal analysis. The Panel Study of Income Dynamics
(PSID) initiated in the United States in 1968 and the German Socio-Economic
Panel (GSOEP) with cross-national equivalence files initiated in 1984 are
often used in comparative life course research to examine labor market and
family dynamics in the life course. Newer longitudinal datasets of younger
populations provide the promise of direct examination of conditions during childhood and adolescence that have consequences for later life. The
National Longitudinal Study of Adolescent Health (Add Health) initiated in
the 1994–1995 school year in a nationally representative sample of seventh
to twelfth graders continues to the present (with the sample reaching ages
24–34 in the 2008 wave) and serially triangulates individual survey data
with social environmental and biological data to capture manifold processes
of aging.
The steadfast maintenance of such datasets is required for life course
research to proceed, to provide solidly grounded explanations of the
life course process and to inform policies that influence the quality of
life. However, the same globalization processes that are implicated in
destandardizing life courses and increasing socioeconomic inequalities
across countries threaten the continuation of the studies mentioned above
and the initiation of new studies in parts of the world where they are needed.
COMPARATIVE STUDIES OF THE LIFE COURSE
Context matters in human development. In addition, theory is advanced only
in the context of comparisons. Two major sources for comparisons of the
life course are history, primarily through cohort studies, and nation-state or
region or meaningful subgroupings within these geographical units such as
race/ethnic, class, or gender groupings. The proliferation of comparable longitudinal databases is facilitating both temporal and contextual comparison.
However, data must be accompanied by analytical tools that can exploit them
and, over time, improve them. Fortuitously, new statistical techniques have
coincided with the spread of long-running longitudinal studies.
Life table methods helped to enhance and expand life course research over
four decades ago. These dynamic methods have been extended to deal with
the diverse properties of samples and variables, including their temporal
characteristics, in order to arrive at reliable causal relationships. These methods were developed further to examine survival (or duration) processes and
instantaneous transition rates and their causes over time. Their capacity to

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track multiple transitions over time (trajectories), including reversible processes (as in the case of leaving school and then returning to school; marrying, divorcing, and remarrying; or becoming ill, recovering, or dying) have
pushed life course research to the frontiers discussed earlier.
Other analytic methods have been developed to move beyond examination
of average tendencies to capture the underlying diversity of aging populations. Latent class and latent trajectory models (or mixture models) can sort
populations into clusters of individuals with similar temporal characteristics
of the life course to capture heterogeneity in populations. Multi-level models
that nest transition or event trajectories within higher level units (individuals; families; schools; nation-states; etc.) can accommodate for the impact of
unmeasured factors associated with contexts. Such methods help to account
for unmeasured or latent heterogeneity in populations that would otherwise
be unobservable using different methods.
INTERDISCIPLINARY COLLABORATION IN A DATA-RICH ENVIRONMENT
The challenges are for data to fit the requirements of existing analytic methods and for new methods to be developed to handle the idiosyncracies of
new and different data. In a data-rich environment, the need for interaction with computational disciplines is more and more pressing. Quantitative
social scientists have played important roles over four decades of research
on the life course, but the explosion of data and the possibilities for linking diverse databases, including longitudinal surveys with administrative,
political, geographic information systems (GIS), DNA databases, census, epidemiologic data, among others, requires a broader base of collaboration. The
incentives for such collaboration have traditionally come from governmental
agencies or private enterprises who are convinced of the value of such work.
However, the life course project will also need the researchers themselves to
reach out to other scientists to move its frontiers forward.
SUMMARY AND CONCLUDING COMMENTS
Aging and life course research can be viewed as a progressive research program that has developed steadily since the 1960s with strong foundations
that have motivated several frontiers of research. These foundations have
generated new questions. Similarly, data on the life course have accumulated over the same period and culminated in comparable long-running
longitudinal datasets that make the observation of the life courses of
different historical cohorts and different national and cultural populations
possible. Life courses have been changing as biographies have encountered history. Globalization forces over recent decades have exerted forces to

Aging and the Life Course

15

de-standardize the life course and to introduce growing inequalities between
and within cohorts. Population aging has coincided with globalization to
influence the capacities of nation-states to provide life course protections
against the hazards of globalization and random shocks. Matching rich
longitudinal data with robust analytic techniques and comparing these
observations across countries constitutes the current strength of life course
research that is advancing theory.
FURTHER READING
Alwin, D., McCammon, R. J., Wray, L. A., & Rodgers, W. L. (2008). Population processes and cognitive aging research. In S. M. Hofer & D. F. Alwin (Eds.), Handbook
of cognitive aging—Interdisciplinary perspectives (pp. 69–89). Thousand Oaks, CA:
Sage Publications.
Blossfeld, H.-P., Buchholz, S., & Kurz, K. (Eds.) (2011). Ageing populations, globalization
and the labor market: Comparing late working life and retirement in modern societies.
Cheltenham, England: Edward Elgar.
Carstensen, L. (2006). The influence of a sense of time on human development. Science, 312, 1913–1915.
DiPrete, T., & Eirich, G. (2006). Cumulative advantage as a mechanism for inequality:
A review of theory and evidence. Annual Review of Sociology, 32, 291–197.
Mayer, K. U. (2004). Whose lives? How history, societies and institutions define and
shape life courses. Research in Human Development, 1, 161–187.
Mayer, K. U. (2009). New directions in life course research. Annual Review of Sociology,
35, 413–433.
O’Rand, A. M. (2011). The devolution of risk and the changing life course. Social
Forces, 90, 1–16.
Shanahan, M. J., & Macmillan, R. (2008). Biography and the sociological imagination:
Contexts and contingencies. New York, NY: W. W. Norton & Company.
Shostak, S., & Freese, J. (2011). Gene-environment interaction and medical sociology.
In C. E. Bird, A. M. Fremont, S. Timmermans & P. Conrads (Eds.), Handbook of
medical sociology (6th ed., pp. 418–434). Nashville, TN: Vanderbilt University Press.

ANGELA M. O’RAND SHORT BIOGRAPHY
Angela M. O’Rand is Professor of Sociology and former Dean of Social
Sciences at Duke University, Durham NC, USA. She has authored and
coauthored books, chapters, and articles on several topics related to the life
course, including: the comparison of US baby boomer life trajectories to
earlier cohorts; the impact of childhood conditions on later life economic and
health statuses; race-ethnic differences in late-life health trajectories; factors
influencing reentry into formal education among mid-life adults; factors

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

influencing diverse retirement patterns among working couples; the spreading privatization of retirement systems in advanced countries; the impact of
globalization and changing pension institutions on the retirement trajectory;
and the growing impact of financial literacy on retirement security. She was
honored in 2008 with the Matilda White Riley Award for her exceptional
contributions to research on aging and the life course by the Section on
Aging and the Life Course of the American Sociological Association. Her
current project focuses on financial literacy as a life course risk.
Personal webpage: http://sociology.duke.edu/people?Gurl=%2Faas%
2FSociology&Uil=aorand&subpage=profile
RELATED ESSAYS
Learning Across the Life Course (Sociology), Jutta Allmendinger and Marcel
Helbig
Close Friendships among Contemporary People (Sociology), Matthew E.
Brashears and Laura Aufderheide Brashears
Patterns of Attachment across the Lifespan (Psychology), Robyn Fivush and
Theodore E. A. Waters
Lifecourse and Aging (Anthropology), Haim Hazan
Social, Psychological, and Physiological Reactions to Stress (Psychology),
Bruce S. McEwen and Craig A. McEwen
Health and Social Inequality (Sociology), Bernice A. Pescosolido
Social Relationships and Health in Older Adulthood (Psychology), Theodore
F. Robles and Josephine A. Menkin
Modeling Life Course Structure: The Triple Helix (Sociology), Tom Schuller
The Role of Cultural, Social, and Psychological Factors in Disease and Illness
(Sociology), Robert A. Scott
Crime and the Life Course (Sociology), Mark Warr and Carmen Gutierrez



Aging and the Life Course
ANGELA M. O’RAND

Abstract
This essay reviews major elements of aging and life course research, its foundations, frontiers, and research challenges. This research examines how human lives
are organized and manifested across the life span in different environments. The first
foundation of life course research is the historical observation of the institutionalization of the life course; that is, how it became standardized in industrialized contexts
through the operation of work, family and state institutions and how it is increasingly
destandardized in the new global economy. The second foundation is the examination of the life course as a process that is manifold and cumulative: manifold because
it consists of intertwining roles and events over time and cumulative because it consists of sequentially contingent transitions and path-dependent processes. The third
foundation is the recognition of the formative and enduring impact of exposures to
severe life conditions or major sustained macro events such as wars or disasters. The
stress process is the fourth foundation that addresses how stresses over the life course
shape its trajectory. Finally, cognition and emotion over the life span serve as a foundation for the major psychological experience of aging. Three frontiers of life course
research are highlighted: the individualization of the life course and the devolution
of risk; cumulative advantage and cumulative disadvantage as major processes of life
course inequalities; and biological processes and the life course. The essay ends with
consideration of life course data and methods and the challenges of interdisciplinary
research.

INTRODUCTION
The question of how human lives are organized and manifested over the
life span has occupied scholars from many disciplines including gerontology, demography, psychology, sociology, history and other social science
specialties, the humanities, and some biological sciences. These disciplines
have focused on different aspects of aging or the successive phases of the
life course, which constitutes a manifold process comprised of interwoven
components that are distinct but interdependent in complex ways over
time. As such, human biographies are products of the multiplex interactions
among biological, psychological, social-structural, and cultural-historical
factors as individuals age from birth to death. Biological aging formatively
Emerging Trends in the Social and Behavioral Sciences. Edited by Robert Scott and Stephen Kosslyn.
© 2015 John Wiley & Sons, Inc. ISBN 978-1-118-90077-2.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

proceeds toward the limit of human life spans, but is constrained in the
process by psychosocial differences, opportunity structures and life chances,
cultural schema, and historical conditions that produce differences in human
lives across and within age-groups. These constraints differentiate the life
courses of human cohorts in ways that result in cumulative disparities in
psychological and physical health and mortality, socioeconomic inequalities
spanning childhood and adulthood, and diverse psychosocial cognitions
and identities, among other differences.
The life course framework has emerged over the past six decades as a
product of the convergence of several traditions in US and European social
sciences concerned with common or related problems. The doubling of
life expectancy around the world over the past 200 years has established
aging as a central existential phenomenon that drives historical and social
change and which, in turn, is a result of social forces related to the control
of diseases of various kinds in different periods, economic development
and global restructuring, and social institutions regulating normative life
transitions, life scripts, social inequalities, and life-and-death processes.
At the population level, aging is defined by the demographic transition
from high mortality and high fertility to steeply declining rates of both in
relationship to differential economic development across countries over
this long period. The demographic transition has been accompanied in
recent decades by an epidemiologic transition in which chronic disease has
superseded infectious disease as the dominant cause of poor health or death
in the most advanced countries where population aging has reached its
highest levels.
At the individual and cohort levels, the aging experience is defined by life
course processes that reflect the interactions among biological, institutional,
economic, historical, and psychosocial factors. Cohorts consist of individuals
who encounter history at the same ages together, but who have differential
experiences that result from these encounters.
This essay will emphasize aging at the individual and cohort levels of
analysis, although aging at the population level provides a historical context
that has independent effects on the individual life course and the aggregate
experiences of cohorts, especially on social patterns related to differential
employment opportunities across ages and retirement policies for the old.
The confluence of foundational research from several traditions has identified five general factors that shape and condition the length of and quality
of life for individuals and cohorts: the institutionalization of the life course;
the manifold, cumulative life course; fundamental causes and situational
imperatives; the stress process; and cognition and emotion over the life span.
The identification of these factors has propelled life course research and

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3

generated several current research fronts or cutting-edge research agendas
that will be identified later in this essay.
FOUNDATIONAL RESEARCH
INSTITUTIONALIZATION OF THE LIFE COURSE
The major foundation of aging and life course research focuses on the institutional and cultural origins, and ongoing construction and reconstruction,
of the phases of life defined by age-related roles, institutional policies, and
long-lived traditions. The institutional tradition identifies social regularities
in the aging process and their bases in social structure and culture. It maps
the domains of life, including family, education, work, health, citizenship,
and leisure, among others, defined by institutions, and investigates their synchronization or interconnectedness over time. It also examines the processes
of inclusion and exclusion that allocate populations across institutional sectors and into status groups by age, gender, race/ethnicity, citizenship, nativity, and other socially meaningful categories with differential social obligations and rights with age.
The tripartite life course has been described by Martin Kohli as the dominant standardized form in industrial (or work) societies with age-related
roles organized for the young around education, for adults around work
and family, and for the old around retirement. State, market, civic, and other
institutions complement each other to construct and reinforce this configuration. Educational systems, age laws protecting youth from social risks (e.g.,
child labor, alcohol, and driving), and auxiliary civic programs developed
to support children’s development and socialization, among other institutions, define the first tripartite phase. The adult phase is also constructed by
legal and traditional systems regulating marriage, parenthood, the employment sector (employers and workers), social protections of individuals and
families, civil activities, and social behaviors. Finally, retirement institutions
define the last phase, including its timing, social and economic entitlements,
and cultural status.
Much research has focused on major transitions in the tripartite life course,
particularly the transition to adulthood and the transition to retirement. The
transition to adulthood is observed as a demographically dense sequence
of multiple transitions from adolescence to adulthood that signify movement towards social independence from the family of origin. These transitions include finishing or leaving school, leaving home, entering the military,
starting work, marriage, and pregnancy and childbirth. The sequencing of
these transitions was normatively regulated for several generations, but is

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

undergoing change across countries. Demographic researchers have characterized this change as “the second demographic transition,” which includes
remaining in education until later ages, delaying marriage or never marrying, cohabitation, and childbirth outside of marriage and childlessness.
Changing gender roles are implicated in this transition as women complete
higher education at higher rates and enter and stay in the labor market during
longer periods in their lives. One welfare state theorist, Gösta Esping Anderson, refers to this process as defamilization.
The transition to retirement includes the exit from income from paid work
to income from a pension. Retirement institutions have varied across countries in their regulation of the age(s) of retirement of different subgroups;
however, the fiscal pressures of population aging in advanced countries,
where the ratios of workers to retirees have declined, have impelled efforts
to extend the retirement age to later years. Retirement institutions have also
varied in the mix of social, occupational, and private sources of pensions.
Social pensions are usually based on rules of entitlement not necessarily
connected to employment. Countries with more liberal welfare institutions
(e.g., USA, and UK) have historically favored occupational and private
sources of pension income, while social democratic (e.g., Norway, and Sweden) and corporatist governments (e.g., Germany, and The Netherlands),
respectively, have provided higher ratios of social benefits to retirees. However, population aging and global macroeconomic forces have encouraged
the latter to shift in the direction of occupational and private savings regimes
similar to liberal states to offset the rising costs of social pension systems that
are less sustainable than in the past. Proposals for gender-neutral benefit
policies and for later ages of normal retirement are spreading throughout
the advanced and developing world.
THE MANIFOLD, CUMULATIVE LIFE COURSE
The second foundation of life course research focuses on the more finely
gauged temporal dynamics of aging beyond the simpler phasic approach
summarized above. In this line of research the life course is examined as a
manifold phenomenon of intertwining cumulative processes. The two major
components of this research include the ideas that (i) lives are lived simultaneously across multiple domains (education, work, family, health) where
experiences in co-occurring roles or with co-occurring events are mutually
influential or interdependent and (ii) lives are path-dependent and comprised of chains of sequentially contingent transitions. The first component
emphasizes the manifold structure of lives over time. It addresses the phenomena that individuals have multiple “careers” as they age—educational
careers, family careers, work careers, health histories, and so on—that are

Aging and the Life Course

5

mutually influential. Extended educational careers tend to delay work,
marriage and childbearing, that early exits from education are associated
with earlier childbearing for women and earlier work for men. Loss of a
job can precipitate returning to schooling or a decline in mental health. The
onset of a physical disability increases the likelihood of loss of employment
and/or exposure to poverty. Long-term unemployment increases the onset
of cardiovascular diseases, and so on.
This component also includes the idea of “linked lives” based on the work
of Glen H. Elder, Jr. and his colleagues over several decades. The manifold
life courses of related individuals influence each other. Hence, the loss of a job
by a working father can have an impact on the course of his children’s lives.
Alternatively, the early parenthood of a single mother significantly predicts
the repetition of this pattern in the next generation.
The second component emphasizes the cumulative processes that lead
to stratification and individualization in aging cohorts. Later statuses and
events in the life course are contingent on earlier statuses and events.
Sequential contingency reflects aging as a social selection process across
individuals, with increasing intra-individual continuities as they age.
However, the temporal characteristics of sequential contingency are complex. First, the order and timing of some transitions in the life course are
consequential for later life outcomes, especially if order or timing has strong
normative underpinnings or institutional requisites. For example, adolescent childbirth outside of marriage is associated with the lower likelihood
of high school completion and higher risks for poverty later. Second, the
temporal proximity of earlier and later transitions can have quite different
effects. The loss of a job that is rapidly replaced by a new one increases the
probability of future job and income stability. Alternatively, the duration of
unemployment negatively affects reemployment and increases the risk for
poverty.
Sequential contingency generates differentiation in aging cohorts as individual lives become increasingly distinct. Glen H. Elder, Jr has identified the
“accentuation principle” in life course research that observes that individuals’ earlier behaviors and preferences are not only continued but often amplified across succeeding transitions. The famous Bennington Study follow-up
by Duane F. Alwin, Ronald L. Cohen, and Theodore M. Newcomb demonstrates this principle in the longitudinal study of women’s political attitudes
over time and their selections of spouses with similar attitudes.
FUNDAMENTAL CAUSES AND SITUATIONAL IMPERATIVES
In countries and regions with weaker institutional protections against life
course risks such as poverty or illness inequality is pervasive in aging

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

cohorts, beginning with childhood. Research on numerous manifest life
course outcomes, including health disparities and economic inequalities,
repeatedly demonstrates the enduring impacts of childhood conditions and
opportunity structures for young adults on health, mortality and economic
well-being in later life. Early exposures to poverty and poor health exert a
social gravity on the later life course through observable processes of exclusion from or limited access to resources such as education. Fundamental
cause theory argues further that much of the effect of early poverty and
poor health is latent and not readily observable until later in life. The long
latency of these exposures exists cognitively and physiologically, masking
scars or hidden injuries that are nevertheless consequential. As such, this
body of work is interested in the question of how adversity “gets under
the skin.” Further, the theory argues that statistical mediation of the effects
on childhood adversity by intervening variables does not diminish the
fundamental and pervasive impact of these conditions throughout life.
In a similar vein, Glen H. Elder, Jr argues that negatively disruptive life
events such as job loss as well as severe and sustained large-scale events
such as economic depressions and wars have enduring manifest and latent
impacts on lives. These situational imperatives can redirect lives or amplify
earlier behaviors and perceptions that have developed over the life course.
THE STRESS PROCESS
The stress process is a widely used model in medical sociology developed
by Leonard I. Pearlin that focuses on individuals’ responses to primary life
stressors (traumatic life events, hardships, challenges) and secondary stressors (role strain and diminished self-concept) that are conditional on social,
economic and personal resources and prior exposures to stressors. The stress
process is cumulative and can be initiated by traumatic experiences and cascade into serial episodes and encounters with new stressors over the life
course. The chief outcome of interest is mental health and its effects on physical health and the general well-being of aging populations and those who
care for them. Successful coping mechanisms and access to social supports
are chief mediators in the stress process.
COGNITION AND EMOTION OVER THE LIFE SPAN
Cognitive aging has been observed for decades by researchers and aging
individuals alike. What has been established in the research is that cognition
is multidimensional; declines in measured cognitive function are significant
and manifestations of a more general neurological decline; and they begin
early in adulthood. Variability in cognition over the life span is traceable

Aging and the Life Course

7

to childhood conditions and their impact on cognitive and socioemotional
development. At the population level, patterns of cognitive decline appear
to be constant across succeeding twentieth-century cohorts, a counterintuitive finding largely attributable to “survival effects” or the ability of lower
cognitive functioning individuals to survive in more recent cohorts as a result
of economic and technological development. The chief conundrum is to separate age effects from the effects of other (sometimes unmeasured) variables,
especially in cross-sectional research.
Cognitive functioning and socioemotional development are associated
over the life course, with the latter strongly implicated in motivation.
Laura Carstensen’s socioemotional selectivity theory argues that over
the life course time horizons shrink and aging individuals are motivated
by different goals than younger individuals. Younger individuals have
longer time horizons and are motivated by knowledge-related or rational
goals associated with developing skills, career aspirations, and instrumental relationships. Older individuals have shorter time horizons and are
motivated more by emotion-related goals associated with the quality of
present-centered social relationships and interactions. The latter age group
also prefers positive over negative information in their observations and
recollections.
CUTTING-EDGE RESEARCH
INDIVIDUALIZATION OF THE LIFE COURSE AND THE DEVOLUTION OF RISK
Globalization processes characterized chiefly by the ascendance of market
and financial practices that generate economic uncertainties are eroding
the twentieth-century state, employment, and family institutions that
constructed the standardized tripartite life course. Employment security has
declined across economic sectors (first in manufacturing, then in service and
other sectors) as market enterprises engaged in price competition seek to
reduce labor costs and increase shareholder returns; advocate deregulation,
privatization and liberalization policies; depend on information and communication technologies for management and information diffusion; and
are increasingly vulnerable to random shocks with distal origins. Arguably,
employment security has been the fulcrum of the tripartite life course by
providing predictable and protected economic resources for workers and
their families, often through corporatist arrangements among employers,
unions, and governments. These resources accompanied by publicly supported educational, health, and retirement policies have anchored the life
course.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Research over the past decade reveals the strongest emergence of globalization forces that make employment security highly problematic. These forces
also have centrifugal impact on the life course since the erosion of social institutions protecting against life course risks leads to the devolution of risk. The
devolution of risk refers to the shift of responsibility for the management of
life course risks to individuals and their families and away from collective
institutions associated with state policies and earlier employment institutions. Shared resources and shared entitlements are disappearing, albeit more
quickly in more liberal regimes than others.
Research reveals that the shift transcends the employment sector to include
educational institutions, which are becoming more decentralized and privatized in liberal states, and family institutions, which are vulnerable to the
centrifugal effects of economic insecurity and the loss of welfare protections.
In the case of the former, education has become less equally accessible across
countries. Family income is affecting educational life chances. In the case of
the latter, family dynamics related to everything from fertility to divorce and
children’s educational opportunities are sensitive to macroeconomic changes
that are not buffered by social protections.
The convergence of globalization with population aging has had particular
impact on the life course, especially in its major transition phases to adulthood and to retirement. Many studies of these transition periods across countries demonstrate growing insecurity for young and older workers alike. The
flexCAREER Project funded by the German Research Foundation and led by
Hans-Peter Blossfeld has compared the changing features of these transitions
across OECD countries. The key concept in this project is the spread of flexible employment (also referred to as precarious work by Arne Kalleberg) characterized by short-term, part-time, and contingent work that is more likely
to be encountered by new labor market entrants, women and racial/ethnic
minorities. This work is characterized by low wages, nonstandard hours, and
little to no benefits. The duration of this exposure in employment careers is
consequential for later employment security. Random shocks such as recessions affect this labor market sector first. Accordingly, research on the transition to adulthood across countries finds observable delays among the young
in entering fulltime stable employment that, in turn, has delayed parental
home-leaving, fertility and family formation in this group. What remains
unclear is the extent to which these patterns are long- or short-lived for these
younger cohorts.
Mid-career and older workers are typically more secure in employment as
a result of their cumulative careers. Indeed, many advanced countries implemented early retirement policies in the twentieth century in order relieve
national labor markets. In the current context, the challenges are different
and contradictory. Early retirement policies present new challenges as life

Aging and the Life Course

9

expectancy increases in the retired population and the ratio of retirees to
younger workers increases. Demographic and policy research over the past
decade reveals the efforts of different countries to diminish the burden of
pension and related costs through legislation for later eligibility for retirement benefits and incentives for the privatization of retirement savings for
younger cohorts. Although pension politics vary across countries given their
political, economic and cultural histories, the shift is clearly towards occupational pensions and private savings regimes, especially but not exclusively
among liberal market states.
Still even mid-career and older workers are being affected by random
shocks and contracting employment opportunities across sectors. Normal
volatility in stock markets has typically had less effect on older workers’
continued employment than extended recessions with sustained high
unemployment. The latter increases the rate and duration of unemployment
among mature workers, decreases the likelihood of reemployment (especially with increased duration of unemployment), increases the likelihood
of flexible employment, and leads to intermittent work careers (careers that
mix part-time and full-time employment with unemployment, underemployment, and disability) that can last for many years before retirement
eligibility.
Research is demonstrating that this stratification of the labor force increases
income inequality in aging cohorts, especially in societies with less regulated economies. The devolution of risk promotes what some researchers
refer to as a free-agent mentality, or an isolated market participant identity
of individualization that challenges earlier notions of class, occupation or
union membership as the strong basis of economic identity. The free agent
mentality also introduces variability in the choices made by individuals that
range from school choices for children, to family migration decisions, to the
retirement transitions. As such, diverse temporal pathways across the transition to adulthood and retirement have been observed. The accumulation of
highly individualized decisions increases the likelihood of increased inequality, especially in the absence of equalizing institutions.
CUMULATIVE ADVANTAGE/DISADVANTAGE
After controlling for the impact of equalizing institutions, the individual
mechanisms whereby economic and health or mortality inequalities in
aging cohorts emerge are the foci of considerable research across countries.
Overall, research across countries and cohorts demonstrates two general
patterns: that inequality pervades the life course, especially in liberal welfare
contexts, and that it is generally cumulative, with successive statuses significantly predicted by earlier statuses. These patterns are labeled as cumulative

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

advantage and cumulative disadvantage. Research is uncovering three
principal loci of these inequalities—inter-cohort variations, childhood
conditions, and educational attainment—although some disagreements
persist in the literature on the relative priority of social selection versus
social causation in the distribution of economic and health disparities.
COHORT VARIATIONS
Recent research has made much ground in disentangling the effects of age,
period and cohort in longitudinal and pooled cross-sectional data. These
innovations have assisted in determining whether social (sex, class, and
race) disparities in outcomes such as health and mortality follow similar
cumulative patterns across birth cohorts. While cumulative patterns are
identified across cohorts, cohort-related changes have also been uncovered:
trajectories of different health conditions (e.g., heart attacks) vary across
cohorts; social inequalities exist in the levels of some health conditions
but not in the growth rates of health conditions; and the widths of social
disparities in health vary across cohorts.
Similar cohort variations have been observed in education. Generally, successive cohorts have increased levels of educational attainment in a nonlinear pattern revealing a slowing of growth. A major cohort-related change is
the change in educational attainment by gender, with women in the most
recent cohorts in advanced countries completing secondary and higher education at higher rates than men. Research suggests that one explanation is that
women’s market roles require more educational credentialing than men’s.
The full explanation has not been uncovered.
CHILDHOOD CONDITIONS
The availability of longitudinal datasets with baseline observations in
childhood and adolescent samples and reliable retrospective survey items
about childhood health and economic adversity have energized scholarship
on the impact of childhood on later life well-being. This research is adding
greater specificity and complexity to the more general fundamental cause
and situational imperative traditions outlined above. Childhood conditions
are associated with later life outcomes through processes of accentuation,
amplification, and mediation depending on the outcome of interest (e.g.,
mortality) and on the intervening life conditions studied (e.g., educational
attainment, employment stability, and marital history) and the temporal properties (trajectories) of these intervening conditions (e.g., timing,
sequence, and duration).

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BIOLOGICAL PROCESSES AND THE LIFE COURSE
Once an unorthodox and largely infeasible line of research in the life course,
the examination of biological processes involved with the life course has
emerged as a frontier. This is driven by some long-standing and some
recently emergent research concerns. A long-standing question in the
demography of the life course regards the health-survival paradox in gender
life expectancy. Researchers have been challenged to explain the female
advantage in survival in spite of women’s poorer health over the life span.
Observable gender-related patterns of health behaviors and social relationships have been implicated in this paradox: men engage in more risky
health behaviors and women maintain more salient and supportive social
ties. However, underlying biological processes have been suspected to be
interdependent with these more readily observable patterns. Similarly, the
variable onset and courses of mental and physical diseases and disabilities
have been tied to observable behaviors, but the contributions of biological
processes to these trajectories have only recently been implicated in these
life course processes. The actual mechanisms of interdependence have only
begun to be specified.
Some longitudinal studies have thus turned to collecting biomarker data
from study participants to study biological markers of physiological and
endocrinological responses to environmentally mediated experiences such
as stress (cortisol) that bear upon the life course. Neuroscience methods
(e.g., fMRA scans) are also increasingly integrated into social psychological
processes of aging including cognitive decline, depression and other mental
health conditions. Finally, heritability and gene–environment interactions
have become the newest candidates for studying the life course from
childhood to old age. Twin studies were the initial method for conducting
experimental and panel research on heritability and gene–environment
interactions in intellectual development and social behaviors. In addition,
recently the life course literature has grown substantially with studies of heritability in such behaviors as alcoholism, church attendance, coping styles,
educational attainment, impulsivity, self-esteem, among other measureable
behaviors with life course implications. Following twin studies, target gene
studies [which examine specific genes associated with diseases such as
Alzheimer’s (APOE) or Parkinson (GBA)] have proliferated to improve
prediction of the risks for and onset of diseases associated with aging.
Similarly, studies focused on DNA sequence variations between individuals
(single-nucleotides polymorphisms—SNPs) use technologies similar to
DNA fingerprinting to look for multiple genetic variations correlated with
observable behaviors and health conditions over the life course. Questions
of feasibility and reliability dominate this research, but this frontier is

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

perhaps the most interdisciplinary growing tip of life course research in the
twenty-first century.
KEY ISSUES FOR FUTURE RESEARCH
STEADFAST MAINTENANCE OF COMPARABLE LONGITUDINAL STUDIES
Although an important place remains in life course research for case studies
and qualitative examinations, frontier research strongly depends on longitudinal data and analytical methods that capture dynamic processes. The life
course consists of events, transitions, and trajectories and sequences that,
when monitored as close as possible in “real” time, permit the tracking of
lives being lived through history. Longitudinal data also can incorporate
causal factors, from retrospective accounts of the earlier biography and
also in “real” time as lives proceed across the multiple domains of family,
education, work, health, leisure, and so on. Hence, the manifold, cumulative
life course becomes observable.
Since the late 1960s, in the United States, Britain, and Europe, longitudinal databases for life course research have proliferated. Today publicly
available databases for aging-related secondary analyses in this area are
available in multiple countries. The US National Institutes of Health
maintains updated listings of and links to many of these data sources (see
http://www.nia.nih.gov/research/dbsr/publicly-available-datasets).
Notably, over the past two decades efforts towards the development and
maintenance of comparable databases across countries have succeeded.
Following the US Health and Retirement Study (HRS) initiated in 1992
and continuing biennially to the present (http://hrsonline.isr.umich.edu),
longitudinal databases using identical and comparable survey items have
been initiated in several countries:
SHARE in Continental Europe and Israel (http://www.share-project.org)
ELSA in England (http://www.ifs.org.uk/elsa/)
KLoSA in South Korea (excl Jeju) (http://klosa.re.kr/KLOSA/default.asp)
MHAS in Mexico (http://www.mhas.pop.upenn.edu/English/home.htm)
All of these databases follow mature samples over the age of 45 at the
first wave. Other national databases developed more recently include: the
Japanese Health and Retirement Study (JHRS) with first wave in 2007;
The Chinese Health and Retirement Longitudinal Survey (CHARLS) with
first wave in 2010; the Longitudinal Aging Study in India (LASI) with first
wave in 2010 or 2011; and the WHO Study of Global Ageing and Adult
Health (SAGE). Many of these surveys include collection of biomarker data

Aging and the Life Course

13

and linkages to health and earnings records that permit a triangulation of
data and the examination of biological and social processes as well as the
reconstruction of past work and health histories.
Databases with more age-heterogeneous and younger samples are also
useful for longitudinal analysis. The Panel Study of Income Dynamics
(PSID) initiated in the United States in 1968 and the German Socio-Economic
Panel (GSOEP) with cross-national equivalence files initiated in 1984 are
often used in comparative life course research to examine labor market and
family dynamics in the life course. Newer longitudinal datasets of younger
populations provide the promise of direct examination of conditions during childhood and adolescence that have consequences for later life. The
National Longitudinal Study of Adolescent Health (Add Health) initiated in
the 1994–1995 school year in a nationally representative sample of seventh
to twelfth graders continues to the present (with the sample reaching ages
24–34 in the 2008 wave) and serially triangulates individual survey data
with social environmental and biological data to capture manifold processes
of aging.
The steadfast maintenance of such datasets is required for life course
research to proceed, to provide solidly grounded explanations of the
life course process and to inform policies that influence the quality of
life. However, the same globalization processes that are implicated in
destandardizing life courses and increasing socioeconomic inequalities
across countries threaten the continuation of the studies mentioned above
and the initiation of new studies in parts of the world where they are needed.
COMPARATIVE STUDIES OF THE LIFE COURSE
Context matters in human development. In addition, theory is advanced only
in the context of comparisons. Two major sources for comparisons of the
life course are history, primarily through cohort studies, and nation-state or
region or meaningful subgroupings within these geographical units such as
race/ethnic, class, or gender groupings. The proliferation of comparable longitudinal databases is facilitating both temporal and contextual comparison.
However, data must be accompanied by analytical tools that can exploit them
and, over time, improve them. Fortuitously, new statistical techniques have
coincided with the spread of long-running longitudinal studies.
Life table methods helped to enhance and expand life course research over
four decades ago. These dynamic methods have been extended to deal with
the diverse properties of samples and variables, including their temporal
characteristics, in order to arrive at reliable causal relationships. These methods were developed further to examine survival (or duration) processes and
instantaneous transition rates and their causes over time. Their capacity to

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

track multiple transitions over time (trajectories), including reversible processes (as in the case of leaving school and then returning to school; marrying, divorcing, and remarrying; or becoming ill, recovering, or dying) have
pushed life course research to the frontiers discussed earlier.
Other analytic methods have been developed to move beyond examination
of average tendencies to capture the underlying diversity of aging populations. Latent class and latent trajectory models (or mixture models) can sort
populations into clusters of individuals with similar temporal characteristics
of the life course to capture heterogeneity in populations. Multi-level models
that nest transition or event trajectories within higher level units (individuals; families; schools; nation-states; etc.) can accommodate for the impact of
unmeasured factors associated with contexts. Such methods help to account
for unmeasured or latent heterogeneity in populations that would otherwise
be unobservable using different methods.
INTERDISCIPLINARY COLLABORATION IN A DATA-RICH ENVIRONMENT
The challenges are for data to fit the requirements of existing analytic methods and for new methods to be developed to handle the idiosyncracies of
new and different data. In a data-rich environment, the need for interaction with computational disciplines is more and more pressing. Quantitative
social scientists have played important roles over four decades of research
on the life course, but the explosion of data and the possibilities for linking diverse databases, including longitudinal surveys with administrative,
political, geographic information systems (GIS), DNA databases, census, epidemiologic data, among others, requires a broader base of collaboration. The
incentives for such collaboration have traditionally come from governmental
agencies or private enterprises who are convinced of the value of such work.
However, the life course project will also need the researchers themselves to
reach out to other scientists to move its frontiers forward.
SUMMARY AND CONCLUDING COMMENTS
Aging and life course research can be viewed as a progressive research program that has developed steadily since the 1960s with strong foundations
that have motivated several frontiers of research. These foundations have
generated new questions. Similarly, data on the life course have accumulated over the same period and culminated in comparable long-running
longitudinal datasets that make the observation of the life courses of
different historical cohorts and different national and cultural populations
possible. Life courses have been changing as biographies have encountered history. Globalization forces over recent decades have exerted forces to

Aging and the Life Course

15

de-standardize the life course and to introduce growing inequalities between
and within cohorts. Population aging has coincided with globalization to
influence the capacities of nation-states to provide life course protections
against the hazards of globalization and random shocks. Matching rich
longitudinal data with robust analytic techniques and comparing these
observations across countries constitutes the current strength of life course
research that is advancing theory.
FURTHER READING
Alwin, D., McCammon, R. J., Wray, L. A., & Rodgers, W. L. (2008). Population processes and cognitive aging research. In S. M. Hofer & D. F. Alwin (Eds.), Handbook
of cognitive aging—Interdisciplinary perspectives (pp. 69–89). Thousand Oaks, CA:
Sage Publications.
Blossfeld, H.-P., Buchholz, S., & Kurz, K. (Eds.) (2011). Ageing populations, globalization
and the labor market: Comparing late working life and retirement in modern societies.
Cheltenham, England: Edward Elgar.
Carstensen, L. (2006). The influence of a sense of time on human development. Science, 312, 1913–1915.
DiPrete, T., & Eirich, G. (2006). Cumulative advantage as a mechanism for inequality:
A review of theory and evidence. Annual Review of Sociology, 32, 291–197.
Mayer, K. U. (2004). Whose lives? How history, societies and institutions define and
shape life courses. Research in Human Development, 1, 161–187.
Mayer, K. U. (2009). New directions in life course research. Annual Review of Sociology,
35, 413–433.
O’Rand, A. M. (2011). The devolution of risk and the changing life course. Social
Forces, 90, 1–16.
Shanahan, M. J., & Macmillan, R. (2008). Biography and the sociological imagination:
Contexts and contingencies. New York, NY: W. W. Norton & Company.
Shostak, S., & Freese, J. (2011). Gene-environment interaction and medical sociology.
In C. E. Bird, A. M. Fremont, S. Timmermans & P. Conrads (Eds.), Handbook of
medical sociology (6th ed., pp. 418–434). Nashville, TN: Vanderbilt University Press.

ANGELA M. O’RAND SHORT BIOGRAPHY
Angela M. O’Rand is Professor of Sociology and former Dean of Social
Sciences at Duke University, Durham NC, USA. She has authored and
coauthored books, chapters, and articles on several topics related to the life
course, including: the comparison of US baby boomer life trajectories to
earlier cohorts; the impact of childhood conditions on later life economic and
health statuses; race-ethnic differences in late-life health trajectories; factors
influencing reentry into formal education among mid-life adults; factors

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

influencing diverse retirement patterns among working couples; the spreading privatization of retirement systems in advanced countries; the impact of
globalization and changing pension institutions on the retirement trajectory;
and the growing impact of financial literacy on retirement security. She was
honored in 2008 with the Matilda White Riley Award for her exceptional
contributions to research on aging and the life course by the Section on
Aging and the Life Course of the American Sociological Association. Her
current project focuses on financial literacy as a life course risk.
Personal webpage: http://sociology.duke.edu/people?Gurl=%2Faas%
2FSociology&Uil=aorand&subpage=profile
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