Interest in adult development and the aging experience is a relatively new area of inquiry. Throughout the first half of the twentieth century, the study of human development was largely the study of child development. Growing awareness of the dramatic global growth in the older population and rising life expectancies led to the emergence of the field of social gerontology. In 1900 people over sixty-five accounted for approximately 4 percent of the U.S. population—less than one in twenty-five. At that time, the average life expectancy (i.e., the average length of time one could expect to live if one were born that year) was forty-seven years. In 2000 adults between twenty and forty-four years of age comprised 36.9 percent of the U.S. population; adults between forty-five and sixty-four made up 22 percent; and those over the age of sixty-five represented 12.8 percent. Today, life expectancy at birth in the United States has risen to 72.5 years for men and 79.3 years for women (U.S. Census Bureau 2000a).
All world regions are experiencing an increase in the absolute and relative size of their older populations. There are, however, substantial differences in the current numbers and expected growth rates of the older population between industrialized and developing countries. For example, 15.5 percent of the population of Europe is aged sixty-five and older. In contrast, only 2.9 percent of sub-Saharan Africa's population is over age sixty-five. The less-developed regions of the world, however, are expected to show significant increases in the size of their older populations in the upcoming decades. For example, the size of the elderly population in sub-Saharan Africa is expected to jump by 50 percent, from 19.3 million to 28.9 million people between 2000 and 2015 (U.S. Census Bureau 2000b).
The democratization of the aging experience or the longevity revolution has also led to a life course revolution (Treas and Bengtson 1982; Skolnick 1991). The changes in mortality have had a profound impact on the concept of adulthood. The odyssey from youth to old age—or the concept of adulthood—can be viewed through many different lens, including chronological, biological, psychological, social, cultural, economic, and legal perspectives.
The distinction between childhood and adulthood varies considerably among cultural and social groups and across historical periods. Aging is not only a biological process; it is also a social process. The personal and social significance of the passage of years is shaped by the cultural age system. All societies divide the life span into recognized stages. These life stages or periods are marked by certain physical, psychological, and/or social milestones. Privileges, obligations, rights, and roles are assigned according to culturally shared definitions of periods of life (Fry 1980; Hagestad and Neugarten 1990). In Western industrialized societies, the life stages are commonly identified as: prenatal stage (from conception until birth); infancy (from birth to the end of the second year of life); early childhood (ages three to six years); middle childhood (six years until puberty); adolescence (start of puberty to adulthood); young adulthood (ages twenty to forty); middle adulthood (ages forty to sixty-five); and later adulthood or old age (sixty-five and older).
These socially constructed life stages are not fixed; rather, they have expanded and contracted in length and new ones have emerged in response to broader social changes. For example, Jeffrey Jensen Arnett (2000) proposes emerging adulthood as a new conception of development for the period from the late teenage years through the twenties (with a focus on the ages of eighteen to twenty-five) in industrialized societies that allow young people a prolonged period of independent role exploration (Arnett 2000). In doing so, he draws parallels between his conception of emerging adulthood to Erik Erikson's concept of prolonged adolescence in industrialized society in which "young adults through role experimentation may find a niche in some section of his society" (Erikson 1968, p. 156).
Arnett (2000) argues that emerging adulthood is distinct demographically. It is the "only period of life in which nothing is normative demographically" (p. 471). Almost all of U.S. adolescents from twelve to seventeen years of age live at home with one or more parents, are enrolled in school, and are unmarried and childless. In contrast, emerging adults' lives are characterized by diversity. About one-third of young persons in the United States go off to college after high school, another 40 percent move out of their parental home for independent living and work, and about 10 percent of men and 30 percent of women remain at home until marriage. About two-thirds of emerging adults experience a period of cohabitation with an intimate partner (Michael et al. 1995). These emerging adults often change residences, including temporarily moving back into their parents' home. It is estimated that about 40 percent of recent cohorts of young adults have returned to their parent's home after moving away (Goldscheider and Goldscheider 1994). Arnett notes that it is with the transition to young adulthood, as more stable choices in love and work are made, that the diversity narrows. As further evidence of emerging adulthood as a distinct life stage, Arnett (2000) cites a survey in which the majority of people in the United States in their late teens and early twenties indicated "somewhat yes and somewhat no" versus an absolute "yes" or "no" to whether they felt they had reached adulthood.
Changes are occurring not only in the social construction of entry to adulthood but also in the social conception of the late stage of adulthood, or old age. The definition of old age as beginning at age sixty-five is a relatively recent phenomenon. It reflects primarily the decision of European countries and the United States, in their creation of their old-age social insurance programs (i.e., national retirement or pension systems) during the first half of the twentieth century, to establish this chronological age as determining eligibility. More recently, the growing numbers of older adults, especially those age eighty and older, has resulted in the redefining of later adulthood into the two distinct life stages or age groups: the younger-old (ages sixty-five to seventy-five) and the older-old or oldest-old (older than seventy-five). Indeed, in many countries, the oldest-old are now the fastest growing portion of the total population. Persons aged eighty and older represented 17 percent of the world's elderly in 2000: 23 percent in developed countries and 13 percent in developing countries (U.S. Census Bureau 2000b). Stressing the relative newness of the oldest-old phenomenon, Richard Suzman and Matilda White Riley (1985, p. 177) emphasized that "less is known about it than any other age group" and that there "is little in historical experience that can help in interpreting it."
Approximately a decade later, similar claims were asserted about middle age. Orville G. Brim, Jr. (1992, p. 171) referred to the middle years as the "last uncharted territory in human development." Concern about the status and welfare of children and the elderly contributed to the scientific study of the biological, psychological, and social development of these two vulnerable populations. This concern led to the enactment of federal and state statutes to protect children and elders. Many researchers' lack of interest in the midlife reflected the predominant view that personality is stable during adulthood. Moreover, from a public policy perspective, adults were not viewed as a vulnerable population requiring protection of "their best interests" by the state.
Bernice L. Neugarten and Nancy Datan (1974) noted that researchers and clinicians constructed dissimilar images of the understudied middle years of adulthood. Whereas researchers characterized young adulthood as a period of major transitions, middle adulthood was often viewed as a plateau with little of significance occurring until old age. In contrast, clinicians often portrayed middle age as a time of crisis. The aging of the baby boomer generation and the sheer number of this cohort entering midlife have had a profound impact on the current interest in this life stage. In 2000 more than 80 million members of the baby boomer generation were between the ages of thirty-five and fifty-four (U.S. Census Bureau 2000a). The interest in middle age spurred the MacArthur Foundation Research Network on Successful Midlife Development (MIDMAC); one of the most significant inter-disciplinary research endeavors devoted to the study of midlife. The studies emerging from the MIDMAC large representative survey of midlife in the United States are reshaping our understanding of these middle years. It was only in 2001 that the first Handbook of Midlife Development, one of the most significant contributions to the field, was published (Lachman 2001).
The period called middle age lacks well-defined boundaries. Michael P. Farrell and Stanley Rosenberg (1981, p. 16) note "like defining a period of history, no one quite agrees when middle age begins or ends." Margie E. Lachman and her colleagues (1994) found that the subjective boundaries of middle age vary positively with age. The older an individual is, the more likely she or he will be to report later entry and exit years as demarcating middle age. Although the ages of forty to sixty are typically considered to be middle-aged, for some persons middle age begins as young as thirty and for others middle age is not perceived as ending until age seventy-five. Middle-aged persons typically report feeling about ten years younger than their chronological age (Montepare and Lachman 1989). As life expectancy increases, the boundaries of middle age may also shift. A National Council on Aging (2000) survey revealed that one-third of Americans in their seventies perceive of themselves as middle-aged. Midlife or middle age does not exist as a concept in all cultures; there is also considerable cultural variation in the social construction of this life stage. Usha Menon (2001) illustrates this variation through a comparative analysis of the conception of middle age and the social roles associated with this stage of life in three societies—middle-class Japan, upper-caste Hindu in rural India, and middle-class Anglo-America.
Whereas childhood and adolescence are often marked by formal rites of passage, the transition from young adult to middle-aged adult is marked neither by special rites of passage nor by predictable chronological events. The transition from young adulthood to middle adulthood is often a gradual one. Social cues, especially changes in family and work domains, may be better indicators of developmental change than chronological age alone.
The midlife research of the past decade has dispelled many of the myths and negative stereo-types of middle age. For most middle-aged adults, their physical health is good, although concerns are expressed about being overweight and future declining health (American Board of Family Practice 1990). Only 7 percent of adults in their early forties, 16 percent of adults in their early fifties, and 30 percent of adults in their early sixties have a disabling health condition (Bumpass and Aquilino 1995). Although middle-aged adults often face a number of family and work stresses, for both men and women there is evidence of a decrease in negative emotions and an increase in positive mood in the middle adult years (Mroczek and Kolarz 1998).
Despite the pervasive and persistent societal view of menopause as a stressful life experience, research has consistently documented that most women pass through menopause with little difficulty. In a longitudinal study of the menopausal transition, Nancy E. Avis and Sonja M. McKinley (1991) found that more than two-thirds of women report relief or neutral feelings about the cessation of menses and that over a four-year period changes in attitudes toward menopause are in a positive or neutral direction. Rather than a crisis, the majority of women viewed their post-menopausal period as a new and fulfilling stage of life. The loss of fertility in menopause is sometimes experienced as a gain in freedom in sexual expression. It is important to stress that there is wide cultural variation in the menopausal experience. For example, Japanese women do not view menopause as a distinct event or a disease; rather it is seen as part of the general aging process. Thus, the physiological changes Japanese women identify as associated with menopause—stiff shoulders, dizziness, headaches, and dry mouth—are changes identified more broadly with growing older. In contrast to U.S. women, few Japanese women identify hot flashes or sweats as symptoms of menopause (Lock 1994).
Adaptation to Aging
To understand adaptation to aging, Laurie Russell Hatch (2000) proposes the adoption of a multilevel life course model organized around four interrelated levels of human experience: personal biographies, social location and membership in social groups, birth cohort, and social context. Personal biography or history encompasses our personal characteristics (i.e., cognitive abilities, personality, health), our patterns of coping and adaptation, and events of our lives.
Social location and membership in social groups recognizes the variability between individuals in human development, both within cultures and across cultures. For example, middle-aged adults from lower socioeconomic groups are more likely to have chronic health conditions. Social location and group membership recognizes the hierarchies of privileges (i.e., gender, social class, sexual orientation, ethnicity) that shape individuals' life experiences and determine the life chances available to them.
Birth cohort and social context analysis recognizes the impact of generational differences. As Matilda White Riley, Anne Foner, and John W. Riley, Jr. (1999) emphasize, changing societies change the life course of individuals, who then during their lives modify society. Cohort variances are particularly relevant to adult development. As Klaus Werner Schaie (2000, p. 262) notes, cohort variance in infancy and childhood studies may be only a "minor disturbance unlikely to overshadow or hide universal developmental laws." In contrast, Schaie stresses cohort variance has "a substantively meaningful role" in the study of adult development. Individual differences in adulthood, prior to old age, are largely modified by environmental context. Examples cited as major contexts that differ dramatically for successive generations include shifts in educational attainment, changes in diet and exercise, and advances in life expectancy.
Although social scientists increasingly emphasize the link between social history and context and adult development, few empirical studies have explored this connection. An exception is Lauren E. Duncan and Gail S. Agronick's (1995) study of the intersection of life stage with the experience of social events. Their research, using three agecohorts of college-educated women, revealed that social events (i.e., World War II, the Eisenhower and Kennedy presidencies, social protests, the women's movement) that coincided with early adulthood were more salient than events that occurred at other life stages.
Duncan and Agronick (1995) also examined more closely the impact of one specific social event, the women's movement. They were particularly interested in a comparative analysis of the effects of the women's movement on college-educated women who experienced this event in early and middle adulthood. Their findings not only underscored that the women's movement was more personally meaningful to women who experienced this event in early adulthood, but also revealed that women of both age cohorts who found the movement important were likely to have higher educational, career, and income attainment, and be more assertive and externally oriented at midlife. Studies, such as the one conducted by Duncan and Agronick (1995), underscore the importance of a multilevel approach to understanding adult development.
Adult and Family Development
Human development occurs within the context of family. Individuals' lives are intertwined with families. It is useful therefore to consider individual development and family development simultaneously, focusing upon the intersection of individual time, family time, and historical time (Hareven 1978). Change occurs at three different levels: the developing individual, dyadic relationships within the family, and the institution of the family ( Jerrome 1994). The family as a social group or institution moves through time in a constantly changing social and cultural environment. The family has a culture of its own that is sustained and elaborated upon by generations of members. Dyadic relationships within the family (i.e., parent and child, siblings) typically last across multiple decades and provide horizontal and vertical linkages in the family system. Change in individual family members, involving personality and family roles, are connected to their own (and other relatives') aging process. As Dorothy Jerrome (1994, p. 8) notes: "The family of childhood becomes the family of middle adulthood, which is replaced by the family of old age. The overlap in membership gradually diminishes until in the end the former group of relatives is completely replaced. Arguably, it is still the same family, though, through the handing down of traditions, family 'ways' and items or objects which link present generations to previous ones."
Within industrialized societies, demographic and social changes of the twentieth century have had profound effects on the family as an institution, dyadic relationships, and members' roles. The shift from high mortality–high fertility to low mortality–low fertility has heightened interest in adult intergenerational relationships. Increased life expectancy coupled with declining fertility has led to the verticalization of the family—a pattern of an increasing number of generations in a family accompanied by a decreasing number of members within a single generation (Bengtson, Rosenthal, and Burton 1990). Thus, family relationships are of unprecedented duration. Parents and children now share five decades of life, siblings may share eight decades of life, and the grandparent-grandchild bond may last two or three decades. Increases in life expectancies have led to middle age becoming the life stage in which adult children typically confront parental declining health and death. About 40 percent of Americans enter midlife with both parents alive, whereas 77 percent leave midlife with no parents alive.
The verticalization of the family in developed countries has also been accompanied by increased educational and labor force opportunities for women, technological advances in reproductive choice, and greater public acceptance of diverse lifestyles and family choices. Adults face unprecedented choices about whether and when to marry, whether to remain married, divorce, or remarry, and whether and when to have children. There is a growing heterogeneity in life course transitions as both men and women move in and out of cohabitation, marriage, parenthood, school, employment, and occupational careers at widely disparate ages and in different sequences. Phenomena that were once clear markers of young adulthood, such as marriage and parenthood, are therefore less predictable and there is greater diversity in the structure of families.
One phenomenon of the changing age structure of families that has received growing attention is the sandwich generation, those adults who find themselves caring for aging parents while still caring for their own children. Recent studies have raised questions, however, about the size of this phenomenon. A study of twelve European Union countries found that only 4 percent of men and 10 percent of women aged forty-five to fifty-four had overlapping responsibilities for children and older adults who required care (Hagestad 2000). Yet, others stress that the definition of caring that is employed greatly influences the obtained percentage of sandwiched adults. For example, the previously described emerging adult life stage (a prolonged period of independent role exploration) has led to a prolonged parenting phase for many midlife adults. Approximately one-third of U.S. parents aged forty to sixty currently coreside with an adult child (Ward and Spitze 1996).
The beginning of the twenty-first century will mean continued heterogeneity in the timing and sequencing of adult life course transitions. There are also reasons to believe that multigenerational bonds will be more important in the upcoming decades. First, the demographic changes of the aging population mean more years of shared living between generations. The impacts of this demographic shift will be particularly profound in developing countries. More than half (59%) of the world's elderly people now live in the developing nations and this proportion is expected to increase to 71 percent by 2030 (U.S. Census Bureau 2002b). Second, we have witnessed a growing importance in the roles of grandparents and other kin in supporting family functioning and well being. Middle-aged and older adults worldwide are increasingly parenting grandchildren and other young kin in families devastated by social problems such as substance abuse, the HIV/AIDs epidemic, civil war, forced migration, and poverty. Finally, despite popular rhetoric in a number of developed nations that the "nuclear family is in decline," research has consistently demonstrated the strength and resilience of family members' bonds across the generations.
See also:Childhood; Elders; Family Development Theory; Filial Responsibility; Grandparenthood; Intergenerational Relations; Later Life Families; Life Course Theory; Menopause; Retirement; Sandwich Generation; Sexuality in Adulthood; Sibling Relationships; Transition to Parenthood
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JUDITH G. GONYEA
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