Chapter 13 Physical and Cognitive Development in Middle Adulthood

Changing Midlife

Many of today's 50-year-olds are in better shape, more alert, and more productive than their 40-year-old counterparts from a generation or two earlier. As more people lead healthier lifestyles and medical discoveries help to slow down the aging process, the boundaries of middle age are being pushed upward. It seems that middle age is starting later and lasting longer for increasing numbers of active, healthy, and productive people. A current saying is "60 is the new 40," implying that many 60-year-olds today are living a life that is as active, productive, and healthy as earlier generations did in their forties. Questions such as, "To which age group do you belong?" and "How old do you feel?" reflect the concept of age identity. A consistent finding is that as adults become older their age identity is younger than their chronological age (Setterson & Trauten, 2009; Westerhof, 2009). One study found that almost half of the individuals 65 to 69 years of age considered themselves middle-aged (National Council on Aging, 2000), and another study found a similar pattern: Half of the 60- to 75-year-olds viewed themselves as middle-aged (Lachman, Maier, & Budner, 2000). And a recent British survey of people over 50 years of age revealed that they perceived middle age to begin at 53 (Beneden Health, 2013). In this study, respondents said that being middle aged is characterized by enjoying afternoon naps, groaning when you bend down, and preferring a quiet night in rather than a night out. Also, some individuals consider the upper boundary of midlife as the age when they make the transition from work to retirement.When Carl Jung studied midlife transitions early in the twentieth century, he referred to midlife as "the afternoon of life" (Jung, 1933). Midlife serves as an important preparation for late adulthood, "the evening of life" (Lachman, 2004, p. 306). But "midlife" came much earlier in Jung's time. In 1900 the average life expectancy was only 47 years of age; only 3 percent of the population lived past 65. Today, the average life expectancy is 79, and 12 percent of the U.S. population is older than 65 (U.S. Census Bureau, 2015). As a much greater percentage of the population lives to older ages, the midpoint of life and what constitutes middle age or middle adulthood are getting harder to pin down (Cohen, 2012). Statistically, the middle of life today is about 39.5 years of age, but most 39-year-olds don't want to be called "middle-aged." What we think of as middle age comes later—anywhere from 40 or 45 to about 60 or 65 years of age. And as more people live longer, the upper boundary of middle age will likely be nudged higher still. In comparison with previous decades and centuries, an increasing percentage of today's population is made up of middle-aged and older adults. In the past, the age structure of the population could be represented by a pyramid, with the largest percentage of the population in the childhood years. Today, the percentages of people at different ages in the life span are more similar, creating what is called the "rectangularization" of the age distribution (a vertical rectangle) (Himes, 2009). Compared to late adulthood, far less research attention has been given to middle adulthood (Lachman, Teshale, & Agrigoroaei, 2015). In a recent U.S. Census Bureau (2012) assessment, more than 102,713,000 people in the U.S. were 40 to 64 years of Page 338 age, which accounts for 33.2 percent of the U.S. population. Given the large percentage of people in middle adulthood and the key roles that individuals in midlife play in families, the workplace, and the community, researchers need to give greater attention to this age period.

menopause

Menopause is the time in middle age, usually in the late forties or early fifties, when a woman's menstrual periods cease completely. The average age at which women have their last period is 51 (Wise, 2006). However, there is large variation in the age at which menopause occurs—from 39 to 59 years of age. Later menopause is linked with increased risk of breast cancer (Mishra & others, 2009).

middle adulthood

Although the age boundaries are not set in stone, we will consider middle adulthood to be the developmental period that begins at approximately 40 years of age and extends to about 60 to 65 years of age. For many people, middle adulthood is a time of declining physical skills and expanding responsibility; a period in which people become more conscious of the young-old polarity and the shrinking amount of time left in life; a point when individuals seek to transmit something meaningful to the next generation; and a time when people reach and maintain satisfaction in their careers. In sum, middle adulthood involves "balancing work and relationship responsibilities in the midst of the physical and psychological changes associated with aging" (Lachman, 2004, p. 305).

Defining Middle Adulthood

Although the age boundaries are not set in stone, we will consider middle adulthood to be the developmental period that begins at approximately 40 years of age and extends to about 60 to 65 years of age. For many people, middle adulthood is a time of declining physical skills and expanding responsibility; a period in which people become more conscious of the young-old polarity and the shrinking amount of time left in life; a point when individuals seek to transmit something meaningful to the next generation; and a time when people reach and maintain satisfaction in their careers. In sum, middle adulthood involves "balancing work and relationship responsibilities in the midst of the physical and psychological changes associated with aging" (Lachman, 2004, p. 305). In midlife, as in other age periods, individuals make choices, selecting what to do, deciding how to invest time and resources, and evaluating what aspects of their lives they need to change (Hahn & Lachman, 2015; Robinson, Rickenbach, & Lachman, 2015). In midlife, "a serious accident, loss, or illness" may be a "wake-up call" that produces "a major restructuring of time and a reassessment" of life's priorities (Lachman, 2004, p. 310). For many increasingly healthy adults, middle age is lasting longer. Indeed, a growing number of experts on middle adulthood describe the age period of 55 to 65 as late midlife (Deeg, 2005). Compared with earlier midlife, late midlife is more likely to be characterized by the death of a parent, the last child leaving the parental home, becoming a grandparent, preparing for retirement, and in most cases actual retirement. Many people in this age range experience their first confrontation with health problems. Overall, then, although gains and losses may balance each other in early midlife, losses may begin to outweigh gains for many individuals in late midlife (Baltes, Lindenberger, & Staudinger, 2006). Margie Lachman and her colleagues (2015) recently described middle age as a pivotal period because it is a time of balancing growth and decline, linking earlier and later periods of development, and connecting younger and older generations. Keep in mind, though, that midlife is characterized by individual variations (Hayslip, Pruett, & Caballero, 2015; Lachman, Agrigoroaei, & Hahn, 2016; List & others, 2015). As life-span expert Gilbert Brim (1992) commented, middle adulthood is full of changes, twists, and turns; the path is not fixed. People move in and out of states of success and failure.

leisure

As adults, not only must we learn how to work well, but we also need to learn how to relax and enjoy leisure (Eriksson Sorman & others, 2014). Leisure refers to the pleasant times after work when individuals are free to pursue activities and interests of their own choosing—hobbies, sports, or reading, for example. In one analysis of research on what U.S. adults regret the most, not engaging in more leisure-time pursuits was one of the top six regrets (Roese & Summerville, 2005). A recent Finnish study found that engaging in little leisure-time activity in middle age was linked to risk of cognitive impairment in late adulthood (23 years later) (Virta & others, 2013). Another recent study revealed that middle-aged individuals who engaged in high levels of leisure-time physical activity were less likely to have Alzheimer disease 28 years later (Tolppanen & others, 2015). Also, the type of leisure activity may be linked to different outcomes. A recent study found that engaging in higher complexity of work before retirement was associated with less cognitive decline during retirement (Andel, Finkel, & Pedersen, 2016). However, when those who had worked in occupations with fewer cognitive challenges prior to retirement engaged in physical (sports, walking) and cognitive (reading books, doing puzzles, and playing chess) leisure activities during retirement, they showed less cognitive decline. Further, a study revealed that middle-aged adults who engaged in active leisure-time pursuits had a higher-level cognitive performance in late adulthood (Ihle & others, 2015). And in another recent study, individuals who engaged in a greater amount of sedentary screen-based leisure time activity (TV, video games, computer use) had shorter telomere length (telomeres cover the end of chromosomes and as people age their telomeres become shorter and this shorter telomere length is linked to earlier mortality) (Loprinzi, 2015).

Leisure

As adults, not only must we learn how to work well, but we also need to learn how to relax and enjoy leisure (Eriksson Sorman & others, 2014). Leisure refers to the pleasant times after work when individuals are free to pursue activities and interests of their own choosing—hobbies, sports, or reading, for example. In one analysis of research on what U.S. adults regret the most, not engaging in more leisure-time pursuits was one of the top six regrets (Roese & Summerville, 2005). A recent Finnish study found that engaging in little leisure-time activity in middle age was linked to risk of cognitive impairment in late adulthood (23 years later) (Virta & others, 2013). Another recent study revealed that middle-aged individuals who engaged in high levels of leisure-time physical activity were less likely to have Alzheimer disease 28 years later (Tolppanen & others, 2015). Also, the type of leisure activity may be linked to different outcomes. A recent study found that engaging in higher complexity of work before retirement was associated with less cognitive decline during retirement (Andel, Finkel, & Pedersen, 2016). However, when those who had worked in occupations with fewer cognitive challenges prior to retirement engaged in physical (sports, walking) and cognitive (reading books, doing puzzles, and playing chess) leisure activities during retirement, they showed less cognitive decline. Further, a study revealed that middle-aged adults who engaged in active leisure-time pursuits had a higher-level cognitive performance in late adulthood (Ihle & others, 2015). And in another recent study, individuals who engaged in a greater amount of sedentary screen-based leisure time activity (TV, video games, computer use) had shorter telomere length (telomeres cover the end of chromosomes and as people age their telomeres become shorter and this shorter telomere length is linked to earlier mortality) (Loprinzi, 2015).Leisure can be an especially important aspect of middle adulthood (Parkes, 2006). By middle adulthood, more money may be available to many individuals, and there may be more free time and paid vacations. In short, midlife changes may produce expanded opportunities for leisure. For many individuals, middle adulthood is the first time in their lives when they have the opportunity to explore their leisure-time interests. How Would You...? As a psychologist, how would you explain the link between leisure and stress reduction to a middle-aged individual? Adults in midlife need to begin preparing psychologically for retirement. Developing constructive and fulfilling leisure-time activities in middle adulthood is an important part of this preparation (Gibson, 2009). If an adult chooses activities that can be continued into retirement, the transition from work to retirement can be less stressful.

Information Processing

As we saw in the coverage of theories of development and of cognitive development from infancy through adolescence, the information-processing approach provides another way to examine cognitive abilities. Among the information-processing changes that take place in middle adulthood are those involved in speed of processing information, memory, and expertise. Speed of Information Processing As we just discussed, in Schaie's (1996, 2013) Seattle Longitudinal Study, perceptual speed begins declining in early adulthood and continues to decline in middle adulthood. A common way to assess speed of information processing is through a reaction-time task, in which individuals simply press a button as soon as they see a light appear. Middle-aged adults are slower to push the button when the light appears than young adults are (Dirk & Schmiedek, 2012; Salthouse, 2009, 2012). However, keep in mind that the decline is not dramatic—less than 1 second in most investigations. Also, in a longitudinal study, a smaller decline in processing speed in middle and late adulthood was one of the key predictors of living longer (Aichele, Rabbitt, & Ghisletta, 2016). Memory In Schaie's (1994, 1996, 2013) Seattle Longitudinal Study, verbal memory peaked in the fifties. However, in some other studies, verbal memory has shown a decline in middle age, especially when assessed in cross-sectional studies (Salthouse, 2009). For example, when asked to remember lists of words, numbers, or meaningful prose, younger adults outperformed middle-aged adults (Salthouse & Page 348 Skovronek, 1992). Although there still is some controversy about whether memory declines during middle adulthood, most experts conclude that it does decline, at least in late middle age (Ferreira & others, 2015; Salthouse, 2014). Aging and cognition expert Denise Park (2001) argues that starting in late middle age, more time is needed to learn new information. The slowdown in learning new information has been linked to changes in working memory, the mental "workbench" where individuals manipulate and assemble information when making decisions, solving problems, and comprehending written and spoken language (Baddeley, 2007, 2012). In this view, in late middle age, working memory capacity—the amount of information that can be immediately retrieved and used—becomes more limited. Memory decline is more likely to occur among individuals who don't use effective memory strategies, such as organization and imagery (Hoyer & Roodin, 2009). By organizing lists of phone numbers into different categories or imagining the phone numbers as representing different objects around the house, many people can improve their memory in middle adulthood. Expertise Because it takes so long to attain, expertise often shows up more in middle adulthood than in early adulthood (Charness & Krampe, 2008). Recall that expertise involves having extensive, highly organized knowledge and understanding of a particular domain. Developing expertise and becoming an "expert" in a field usually is the result of many years of experience, learning, and effort (Ericsson & others, 2016). Adults in middle age who have become experts in their fields are likely to do the following: rely on their accumulated experience to solve problems; process information automatically and analyze it more efficiently when solving a problem; devise better strategies and shortcuts to solving problems; and be more creative and flexible in solving problems.

Meaning in Life

Austrian psychiatrist Viktor Frankl's mother, father, brother, and wife died in the concentration camps and gas chambers in Auschwitz, Poland, during World War II. Frankl survived the concentration camp and went on to write about the search for meaning in life. In his book, Man's Search for Meaning, Frankl (1984) emphasized each person's uniqueness and the finiteness of life. He believed that examining the finiteness of our existence and the certainty of death adds meaning to life. If life were not finite, said Frankl, we could spend our life doing just about whatever we pleased because our time would be unlimited. Frankl said that the three most distinctly human qualities are spirituality, freedom, and responsibility. Spirituality, in his view, does not have a religious underpinning. Rather, it refers to a human being's uniqueness of spirit, philosophy, and mind. Frankl proposed that people ask themselves questions about why they exist, what they want from life, and what their lives mean. It is in middle adulthood that individuals begin to face death more often, especially the deaths of parents and other older relatives. As they become increasingly aware of the diminishing number of years ahead of them, many individuals in middle age begin to ask and evaluate the questions that Frankl proposed. And meaning-making coping is especially helpful in times of chronic stress and loss.Researchers are increasingly studying the factors involved in a person's exploration of meaning in life and exploring whether developing a sense of meaning in life is linked to positive developmental outcomes (Park, 2010, 2012). In research studies, many individuals state that religion played an important role in increasing their exploration of meaning in life (Krause, 2008, 2009; Krause & Hayward, 2016). Studies also suggest that individuals who have found a sense of meaning in life are physically healthier and happier, and Page 353 experience less depression, than their counterparts who report that they have not discovered meaning in life (Krause, 2009). Having a sense of meaning in life can lead to clearer guidelines for living one's life and enhanced motivation to take care of oneself and reach goals. A higher level of meaning in life also is linked to a higher level of psychological well-being and physical health (Park, 2012).

CAREERS, WORK, AND LEISURE

Careers, Work, and Leisure What are some issues that workers face in midlife? What role does leisure play in the lives of middle-aged adults?

THE NATURE OF MIDDLE ADULTHOOD

Changing Midlife Many of today's 50-year-olds are in better shape, more alert, and more productive than their 40-year-old counterparts from a generation or two earlier. As more people lead healthier lifestyles and medical discoveries help to slow down the aging process, the boundaries of middle age are being pushed upward. It seems that middle age is starting later and lasting longer for increasing numbers of active, healthy, and productive people. A current saying is "60 is the new 40," implying that many 60-year-olds today are living a life that is as active, productive, and healthy as earlier generations did in their forties. Questions such as, "To which age group do you belong?" and "How old do you feel?" reflect the concept of age identity. A consistent finding is that as adults become older their age identity is younger than their chronological age (Setterson & Trauten, 2009; Westerhof, 2009). One study found that almost half of the individuals 65 to 69 years of age considered themselves middle-aged (National Council on Aging, 2000), and another study found a similar pattern: Half of the 60- to 75-year-olds viewed themselves as middle-aged (Lachman, Maier, & Budner, 2000). And a recent British survey of people over 50 years of age revealed that they perceived middle age to begin at 53 (Beneden Health, 2013). In this study, respondents said that being middle aged is characterized by enjoying afternoon naps, groaning when you bend down, and preferring a quiet night in rather than a night out. Also, some individuals consider the upper boundary of midlife as the age when they make the transition from work to retirement.When Carl Jung studied midlife transitions early in the twentieth century, he referred to midlife as "the afternoon of life" (Jung, 1933). Midlife serves as an important preparation for late adulthood, "the evening of life" (Lachman, 2004, p. 306). But "midlife" came much earlier in Jung's time. In 1900 the average life expectancy was only 47 years of age; only 3 percent of the population lived past 65. Today, the average life expectancy is 79, and 12 percent of the U.S. population is older than 65 (U.S. Census Bureau, 2015). As a much greater percentage of the population lives to older ages, the midpoint of life and what constitutes middle age or middle adulthood are getting harder to pin down (Cohen, 2012). Statistically, the middle of life today is about 39.5 years of age, but most 39-year-olds don't want to be called "middle-aged." What we think of as middle age comes later—anywhere from 40 or 45 to about 60 or 65 years of age. And as more people live longer, the upper boundary of middle age will likely be nudged higher still. In comparison with previous decades and centuries, an increasing percentage of today's population is made up of middle-aged and older adults. In the past, the age structure of the population could be represented by a pyramid, with the largest percentage of the population in the childhood years. Today, the percentages of people at different ages in the life span are more similar, creating what is called the "rectangularization" of the age distribution (a vertical rectangle) (Himes, 2009). Compared to late adulthood, far less research attention has been given to middle adulthood (Lachman, Teshale, & Agrigoroaei, 2015). In a recent U.S. Census Bureau (2012) assessment, more than 102,713,000 people in the U.S. were 40 to 64 years of Page 338 age, which accounts for 33.2 percent of the U.S. population. Given the large percentage of people in middle adulthood and the key roles that individuals in midlife play in families, the workplace, and the community, researchers need to give greater attention to this age period.

Health and Disease

Health and Disease In middle adulthood, the frequency of accidents declines, and individuals are less susceptible to colds and allergies than in childhood, adolescence, or early adulthood. Page 342 Indeed, many individuals live through middle adulthood without having a disease or persistent health problem. For others, however, disease and persistent health problems become more common in middle adulthood than in earlier life stages. Stress is increasingly being identified as a factor in disease (Jansen & others, 2016; Lagraauw, Kuiper, & Bot, 2015; Sin & others, 2016). The cumulative effect of chronic stress often takes a toll on the health of individuals by the time they reach middle age. A recent study of middle-aged adults found that when they had a high level of allostatic load (wearing down of the body's systems in response to high stress levels), their episodic memory and executive function were harmed (Karlamangia & others, 2013). And a recent study of occupationally active 44- to 58-year-olds revealed that perceived stress symptoms in midlife were linked to self-care disability and mobility limitations 28 years later (Kulmala & others, 2013). Chronic stressors have been linked to a downturn in immune system functioning in a number of contexts, including worries about living next to a damaged nuclear reactor, failures in close relationships (divorce, separation, and marital distress), depression, loneliness, and burdensome caregiving for a family member with progressive illness (Bennett, Fagundes, & Kiecolt-Glaser, 2016; Fagundes & others, 2016; Jaremka, Derry, & Kiecolt-Glaser, 2016). A recent study discovered that chronic stress accelerated pancreatic cancer growth (Kim-Fuchs & others, 2014). Recent research indicates that stress-reducing activities such as yoga, relaxation, and hypnosis have positive influences on immune system functioning (Derry & others, 2015; Kiecolt-Glaser & others, 2014). How individuals react to stressors is linked to health outcomes. In one study, how people reacted to daily stressors in their lives was linked to future chronic health problems (Piazza & others, 2013). Also, in a recent study, adults who did not maintain positive affect when confronted with minor stressors in everyday life had elevated levels of IL-6, an inflammation marker (Sin & others, 2015). And in another recent study, a greater decrease in positive affect in response to daily stressors was associated with earlier death (Mroczek & others, 2015).

working memory

In Schaie's (1994, 1996, 2013) Seattle Longitudinal Study, verbal memory peaked in the fifties. However, in some other studies, verbal memory has shown a decline in middle age, especially when assessed in cross-sectional studies (Salthouse, 2009). For example, when asked to remember lists of words, numbers, or meaningful prose, younger adults outperformed middle-aged adults (Salthouse & Page 348 Skovronek, 1992). Although there still is some controversy about whether memory declines during middle adulthood, most experts conclude that it does decline, at least in late middle age (Ferreira & others, 2015; Salthouse, 2014). Aging and cognition expert Denise Park (2001) argues that starting in late middle age, more time is needed to learn new information. The slowdown in learning new information has been linked to changes in working memory, the mental "workbench" where individuals manipulate and assemble information when making decisions, solving problems, and comprehending written and spoken language (Baddeley, 2007, 2012). In this view, in late middle age, working memory capacity—the amount of information that can be immediately retrieved and used—becomes more limited.

Religion and Adult Lives

In research that was part of the Midlife in the United States Study (MIDUS), more than 70 percent of U.S. middle-aged adults said that they are religious and that they consider spirituality a major part of their lives (Brim, 1999). In thinking about religion and adult development, it is important to consider the role of individual differences. Religion is a powerful influence in some adults' lives, whereas it plays little or no role in others' lives (Krause & Hayward, 2016). In a longitudinal study of individuals from their early thirties through their late sixties and early seventies, a significant increase in spirituality occurred between late middle (mid-fifties/early sixties) and late adulthood (Wink & Dillon, 2002) (see Figure 4). And a recent survey found that 77 percent of 30- to 49-year-olds and 84 percent of 50- to 64-year-olds reported having a religious affiliation (compared with 67 percent of 18- to 29-year-olds and 90 percent of adults 90 years of age and older) (Pew Research Center, 2012).Females have consistently shown a stronger interest in religion than males have (Bijur & others, 1993). Compared with men, they participate more in both organized and personal forms of religion, are more likely to believe in a higher power or presence, and are more likely to feel that religion is an important dimension of their lives. In the longitudinal study just described, the spirituality of women increased more than that of men during the second half of life (Wink & Dillon, 2002).

Mortality Rates

Infectious disease was the main cause of death until the middle of the twentieth century. As infectious disease rates declined and more individuals lived through middle age, chronic disorders increased. These are characterized by a slow onset and a long duration (Kelley-Moore, 2009). Chronic disorders account for 86 percent of total health-care spending in the United States (Qin & others, 2015). In middle age, many deaths are caused by a single, readily identifiable condition, whereas in old age, death is more likely to result from the combined effects of several chronic conditions. For many years heart disease was the leading cause of death in middle adulthood, followed by cancer; however, since 2005 more individuals 45 to 64 years of age in the United States died of cancer, followed by cardiovascular disease (Centers for Disease Control and Prevention, 2015). The gap between cancer and the second leading cause of death widens as individuals age from 45 to 54 and from 55 to 64 years of age. In 2013, about 46,000 45- to 54-year-olds died of cancer and about 35,000 died of cardiovascular disease; about 113,000 55- to 64-year-olds died of cancer and about 73,000 died of cardiovascular disease (Centers for Disease Control and Prevention, 2015). Men have higher mortality rates than women for all of the leading causes of death (Kochanek & others, 2011).

crystallized intelligence

John Horn argues that some abilities begin to decline in middle age, whereas others increase (Horn & Donaldson, 1980). He argues that crystallized intelligence, an individual's accumulated information and verbal skills, continues to increase in middle adulthood, whereas fluid intelligence, one's ability to reason abstractly, begins to decline during middle adulthood (see Figure 1).

Let's complete Chapter 13 and 14!

Let's complete Chapter 13 and 14!

Intelligence

Our exploration of possible changes in intelligence in middle adulthood focuses on the concepts of fluid and crystallized intelligence, cohort effects, and the Seattle Longitudinal Study. How Would You...? As an educator, how would you explain how changes in fluid and crystallized intelligence might influence the way middle-aged adults learn? Fluid and Crystallized Intelligence John Horn argues that some abilities begin to decline in middle age, whereas others increase (Horn & Donaldson, 1980). He argues that crystallized intelligence, an individual's accumulated information and verbal skills, continues to increase in middle adulthood, whereas fluid intelligence, one's ability to reason abstractly, begins to decline during middle adulthood (see Figure 1).Horn's data were collected in a cross-sectional manner. Recall that a cross-sectional study assesses individuals of different ages at the same point in time. For example, a cross-sectional study might assess the intelligence of different groups of 40-, 50-, and 60-year-olds in a single evaluation, such as in 1980. The 40-year-olds in the study would have been born in 1940 and the 60-year-olds in 1920—different eras that offered different economic and educational opportunities. The 60-year-olds likely had fewer educational opportunities as they grew up. Thus, if we find differences between 40- and 60-year-olds on intelligence tests when they are assessed cross-sectionally, these differences might be due to cohort effects related to educational differences rather than to age. By contrast, recall that in a longitudinal study, the same individuals are studied over a period of time. Thus, a longitudinal study of intelligence in middle adulthood might consist of giving the same intelligence test to the same individuals when they are 40, then 50, and then 60 years of age. As we see next, whether data on intelligence are Page 346 collected cross-sectionally or longitudinally can make a difference in what is found about changes in crystallized and fluid intelligence and about intellectual decline.The Seattle Longitudinal Study K. Warner Schaie (1996, 2005, 2010, 2011, 2013) is conducting an extensive study of intellectual abilities in adulthood. Five hundred individuals initially were tested in 1956. New waves of participants are added periodically. The main focus in the Seattle Longitudinal Study has been on individual change and stability in intelligence. The main mental abilities tested are verbal comprehension (ability to understand ideas expressed in words); verbal memory (ability to encode and recall meaningful language units, such as a list of words); numeric ability (ability to perform simple mathematical computations such as addition, subtraction, and multiplication); spatial orientation (ability to visualize and mentally rotate stimuli in two- and three-dimensional space); inductive reasoning (ability to recognize and understand patterns and relationships in a problem and use this understanding to solve other instances of the problem); and perceptual speed (ability to quickly and accurately make simple discriminations in visual stimuli). The highest level of functioning for four of the six intellectual abilities occurred during middle adulthood (Schaie, 2013) (see Figure 2). For both women and men, peak performance on verbal ability, verbal memory, inductive reasoning, and spatial orientation was attained in middle age. Only two of the six abilities—numeric ability and perceptual speed—showed a decline in middle age. Perceptual speed showed the earliest decline, actually beginning in early adulthood. Interestingly, in terms of John Horn's ideas that were discussed earlier, for the participants in the Seattle Longitudinal Study, middle age was a time of peak performance for some aspects of both crystallized intelligence (verbal ability) and fluid intelligence (spatial orientation and inductive reasoning).Notice in Figure 2that declines in functioning for most cognitive abilities began in the sixties, although verbal ability did not drop until the mid-seventies. From the mid-seventies through the mid-nineties, all cognitive abilities showed considerable decline. When Schaie (1994) assessed intellectual abilities both cross-sectionally and longitudinally, he found declines more often in the cross-sectional than in the Page 347 longitudinal assessments. For example, as shown in Figure 3, when assessed cross-sectionally, inductive reasoning showed a consistent decline during middle adulthood. In contrast, when assessed longitudinally, inductive reasoning increased until toward the end of middle adulthood, when it began to show a slight decline. In Schaie's (2009, 2010, 2011, 2013, 2016) view, it is during middle adulthood, not early adulthood, that people reach a peak in their cognitive functioning for many intellectual skills.Such differences across generations involve cohort effects. In a recent analysis, Schaie (2013, 2016) concluded that the advances in cognitive functioning in middle age that have occurred in recent decades are likely due to a combination of factors: educational attainment, occupational structures (increasing numbers of workers in professional occupations with greater work complexity), changes in health care and lifestyles, immigration, and social interventions in poverty. The impressive gains in cognitive functioning in recent cohorts have been documented more clearly for fluid intelligence than for crystallized intelligence (Schaie, 2013). Some researchers disagree with Schaie that middle adulthood is the time when the level of functioning in a number of cognitive domains is maintained or even increases (Finch, 2009). For example, Timothy Salthouse (2009, 2012) has emphasized that a lower level of cognitive functioning in middle adulthood is likely due to age-related neurobiological decline. Salthouse (2014, 2016) also recently argued that a main reason for different trends in longitudinal and cross-sectional comparisons of cognitive functioning is that prior experience with tests increases scores the next time a test is taken.

Career Challenges and Changes

The current middle-aged worker faces several important challenges in the twenty-first century (Brand, 2014). These include the globalization of work, rapid developments in information technologies, downsizing of organizations, pressure to choose early retirement, and concerns about pensions and health care. Globalization has replaced what was once a primarily non-Latino White male workforce in the United States with employees of different ethnic and national backgrounds who have emigrated from different parts of the world. To improve profits, many companies are restructuring, downsizing, and outsourcing jobs. One of the outcomes of this change has been for companies to offer incentives to middle-aged employees who choose to retire early—in their fifties, or in some cases even forties, rather than their sixties. The decline in defined-benefit pensions and increased uncertainty about the fate of health insurance are eroding the sense of personal control among middle-aged workers. As a consequence, many are delaying their retirement from work. Some midlife career changes are self-motivated, while others are the consequence of losing one's job (Moen, 2009a, b). Some individuals in middle age decide that they don't want to continue doing the same work for the rest of their working lives (Hoyer & Roodin, 2009). One aspect of middle adulthood involves adjusting idealistic hopes to reflect realistic possibilities in light of how much time individuals have before they retire and how fast they are reaching their occupational goals (Levinson, 1978). Individuals could become motivated to change jobs if they perceive that they are behind schedule, if their goals are unrealistic, if they don't like the work they are doing, or if their job has become too stressful.A final point to make about career development in middle adulthood is that cognitive factors earlier in development are linked to occupational attainment in middle age. In one study, task persistence at 13 years of age was related to occupational success in middle age (Andersson & Bergman, 2011).

Work in Midlife

The role of work, whether one works in a full-time career, at a part-time job, as a volunteer, or as a homemaker, is central during the middle years (Cahill, Giandrea, & Quinn, 2016; Wang & Shi, 2016). Middle-aged adults may reach their peak in position and earnings. They may also be saddled with multiple financial burdens including rent or mortgage payment, medical bills, home repairs, college tuition, loans to family members, or bills from nursing homes for aging parents. A recent study found that difficulty managing different job demands was associated with poor health in middle-aged adults (Nabe-Nielsen & others, 2014).In 2015 in the United States, 79.4 percent of 45- to 54-year-olds were in the workforce (a decrease of 3.4 percent since 2000) and 64.1 percent of 55- to 64-year-olds were in the workforce (an increase of 8 percent since 2000) (Short, 2015). Later we will describe various aspects of workforce participation among individuals age 65 and over in the United States, which has increased by a remarkable 50 percent since 2000 (Short, 2015).Page 349 How Would You...? As a social worker, what advice would you offer to middle-aged adults who are dissatisfied with their careers? Do middle-aged workers perform their work as competently as younger adults? Age-related declines occur in some occupations, such as air traffic controllers and professional athletes, but for most jobs, no differences have been found in the work performance of young adults and middle-aged adults (Salthouse, 2012). However, leading Finnish researcher Clas-Hakan Nygard (2013) concludes from his longitudinal research that the ability to work effectively peaks during middle age because of increased motivation, work experience, employer loyalty, and better strategic thinking. Nygard also has found that the quality of work done by middle-aged employees is linked to how much their work is appreciated and how well they get along with their immediate supervisors. And Nygard and his colleagues discovered that work ability in middle age was linked to mortality and disability 28 years later (von Bonsdorff & others, 2011, 2012). For many people, midlife is a time of evaluation, assessment, and reflection in terms of the work they are doing and want to do in the future (Cahill, Giandrea, & Quinn, 2016). Among the work issues that some people face in midlife are recognizing limitations in career progress, deciding whether to change jobs or careers, deciding whether to rebalance family and work, and planning for retirement (Sterns & Huyck, 2001).

COGNITIVE DEVELOPMENT

We have seen that middle-aged adults may not see as well, run as fast, or be as healthy as they were in their twenties and thirties. We've also seen a decline in their sexual activity. What about their cognitive skills? Do these skills decline as we enter and move through middle adulthood? To answer this question, we will explore the possibility of age-related changes in intelligence and information processing.

climacteric

What kinds of changes characterize the sexuality of women and men as they go through middle age? Climacteric is a term used to describe the midlife transition during which fertility declines. Let's explore the substantial differences in the climacteric of women and men during middle adulthood.

Sexuality

What kinds of changes characterize the sexuality of women and men as they go through middle age? Climacteric is a term used to describe the midlife transition during which fertility declines. Let's explore the substantial differences in the climacteric of women and men during middle adulthood. Page 343 Menopause Menopause is the time in middle age, usually in the late forties or early fifties, when a woman's menstrual periods cease completely. The average age at which women have their last period is 51 (Wise, 2006). However, there is large variation in the age at which menopause occurs—from 39 to 59 years of age. Later menopause is linked with increased risk of breast cancer (Mishra & others, 2009).In menopause, production of estrogen by the ovaries declines dramatically, and this decline produces uncomfortable symptoms in some women—"hot flashes," nausea, fatigue, and rapid heartbeat, for example (Mitchell & Woods, 2015). However, cross-cultural studies reveal wide variations in the menopause experience (Sievert, 2014). For example, hot flashes are uncommon in Mayan women (Beyene, 1986). Asian women report fewer hot flashes than women in Western societies (Payer, 1991). It is difficult to determine the extent to which these cross-cultural variations are due to genetic, dietary, reproductive, or cultural factors. Menopause overall is not the negative experience for most women that it was once thought to be (Henderson, 2011). Most women do not have severe physical or psychological problems related to menopause. For example, a recent research review concluded that there is no clear evidence that depressive disorders occur more often during menopause than at other times in a woman's reproductive life (Judd, Hickey, & Bryant, 2011). Hormone replacement therapy (HRT) augments the declining levels of reproductive hormone production by the ovaries (Baber & others, 2016; Gambacciani & Levancini, 2015; Thorley, 2016). HRT can consist of various forms of estrogen, usually in combination with a progestin. The National Institutes of Health recommends that women who have not had a hysterectomy and who are currently taking hormones consult with their doctor to determine whether they should continue the treatment. If they are taking HRT for short-term relief of menopausal symptoms, the benefits may outweigh the risks. Many middle-aged women are seeking alternatives to HRT such as regular exercise, dietary supplements, herbal remedies, relaxation therapy, acupuncture, and nonsteroidal medications (Asghari & others, 2016; Goldstein & others, 2016; Mansikkamaki & others, 2016; Nasiri, 2015; Yazdkhasti, Simbar, & Abdi, 2015). A recent study revealed that in sedentary women, aerobic training for six months decreased menopausal symptoms, especially night sweats, mood swings, and irritability (Moilanen & others, 2012). Another recent study found that yoga improved the quality of life of menopausal women (Reed & others, 2014).Sexual Attitudes and Behavior Although the ability of men and women to function sexually shows little biological decline in middle adulthood, sexual activity usually occurs less frequently than in early adulthood (Huhtaniemi, 2014). Career interests, family matters, diminishing energy levels, and routine may contribute to this decline (Avis & others, 2009). In the Sex in America survey, the frequency of sexual activity was greatest for individuals 25 to 29 years old (47 percent had sex twice a week or more) and dropped off for individuals in their fifties (23 percent of 50- to 59-year-old males said they had sex twice a week or more, while only 14 percent of the females in this age group reported this frequency) (Michael & others, 1994). Note, though, that the Sex in America survey may underestimate the frequency of sexual activity of middle-aged adults because the data were collected prior to the widespread use of erectile dysfunction drugs such as Viagra. How does the pattern of sexual activity change when individuals become middle-aged? © Image Source/PunchStock RF How Would You...? As a psychologist, how would you counsel a couple about the ways that the transition to middle adulthood might affect their sexual relationship? Living with a spouse or partner makes all the difference in whether people engage in sexual activity, especially for women over 40 years of age. In one study conducted as part of the Midlife in the United States Study (MIDUS), 95 percent of women in their forties with partners said that they had been sexually active in the last six months, compared with only 53 percent of those without partners (Brim, 1999). By their fifties, 88 percent of women living with a partner have been sexually active in the last six months, but only 37 percent of those who are neither married nor living with someone say they have had sex in the last six months. A large-scale study of U.S. adults 40 to 80 years of age found that early ejaculation (26 percent) and erectile difficulties (22 percent) were the most common sexual problems Page 345of older men (Laumann & others, 2009). In this study, the most common sexual problems of women were lack of sexual interest (33 percent) and lubrication difficulties (21 percent). A person's health in middle age is a key factor in sexual activity in middle age (Field & others, 2013). A recent study of aging adults 55 years and older revealed that their level of sexual activity was associated with their physical and mental health (Bach & others, 2013).

Religion and Health

What might be some of the effects of religion on physical health? Some cults and religious sects encourage behaviors that are damaging to health, such as ignoring sound medical advice. For individuals in the religious mainstream, however, researchers are increasingly finding positive links between religion and physical health (Krause & Hayward, 2016). Researchers have found that religious attendance is linked to a reduction in hypertension (Gillum & Ingram, 2007). And in a recent analysis of a number of studies, adults with a higher level of spirituality/religion had an 18 percent increase in longevity (Lucchetti, Lucchetti, & Koenig, 2011). In this analysis, a high level of spirituality/religion was more closely tied to longevity than 60 percent of 25 other health interventions (such as eating fruits and vegetables and taking statin drugs for cardiovascular disease).Why might religion promote physical health? There are several possible answers (Park, 2013). First, there are lifestyle issues—for example, religious individuals have lower rates of drug use than their nonreligious counterparts (Gartner, Larson, & Allen, 1991). Second are social networks—the degree to which Page 352 individuals are connected to others affects their health. Well-connected individuals have fewer health problems (Hill & Pargament, 2003). Religious groups, meetings, and activities provide social connectedness for individuals. A third answer involves coping with stress—religion offers a source of comfort and support when individuals are confronted with stressful events. A recent study revealed that highly religious individuals were less likely than their moderately religious, somewhat religious, and non-religious counterparts to be psychologically distressed (Park, 2013). Religious counselors often advise people about mental health and coping. To read about the work of one religious counselor, see Careers in Life-Span Development.

PHYSICAL DEVELOPMENT

What physical changes accompany the change to middle adulthood? How healthy are middle-aged adults? How sexually active are they? Physical Changes Although everyone experiences some physical changes due to aging in the middle adulthood years, the rates of this aging vary considerably from one individual to Page 339 another. Genetic makeup and lifestyle factors play important roles in whether chronic disease will appear and when (Simons & others, 2016; Theendakara & others, 2016; Zhu & others, 2016). Middle age is a window through which we can glimpse later life while there is still time to engage in prevention and to influence some of the course of aging (Bertrand, Graham, & Lachman, 2013; Lachman, Teshale, & Agrigoroaei, 2015).Visible Signs One of the most visible signs of change in middle adulthood is physical appearance. The first outwardly noticeable signs of aging usually are apparent by the forties or fifties. The skin begins to wrinkle and sag because of a loss of fat and collagen in underlying tissues (Miyawaki & others, 2016; Pageon & others, 2014). Small, localized areas of pigmentation in the skin produce age spots, especially in areas that are exposed to sunlight, such as the hands and face. For most people, their hair becomes thinner and grayer. Fingernails and toenails develop ridges and become thicker and more brittle. A recent twin study found that twins who had been smoking longer were more likely to have more sagging facial skin and wrinkles, especially in the middle and lower portion of the face (Okada & others, 2013). Since a youthful appearance is valued in our culture, many individuals whose hair is graying, whose skin is wrinkling, whose bodies are sagging, and whose teeth are yellowing strive to make themselves look younger. Undergoing cosmetic surgery, dyeing hair, wearing wigs, enrolling in weight-reduction programs, participating in exercise regimens, and taking heavy doses of vitamins are common in middle age. Many baby boomers have shown a strong interest in plastic surgery and Botox, which may reflect their desire to take control of the aging process (Carruthers & others, 2015; Solish & others, 2016).

RELIGION AND MEANING IN LIFE

What role does religion play in our development as adults? Is discovering the meaning of life an important theme for many middle-aged adults?

Studying is....

the result of Studying

Physical Changes

trength, Joints, and Bones Maximum physical strength often is attained in the twenties. The term sarcopenia refers to age-related loss of muscle mass and strength (Bianchi & others, 2016; Spira & others, 2015). Muscle loss with age occurs at a rate of approximately 1 to 2 percent per year past the age of 50 (Marcell, 2003). Page 340 A loss of strength especially occurs in the back and legs. Obesity is a risk factor for sarcopenia (Cauley, 2015). Recently, researchers have increasingly used the term "sarcopenic obesity" to describe individuals who have sarcopenia and are obese (Lee & others, 2016; Ma & others, 2016). In a recent study sarcopenic obesity was associated with a 24 percent increase in risk for all-cause mortality, with a higher risk of mortality for men than for women (Tian & Xu, 2016). Peak functioning of the body's joints also usually occurs in the twenties. The cartilage that cushions the movement of bones and other connective tissues, such as tendons and ligaments, become less efficient in the middle-adult years, a time when many individuals experience joint stiffness and greater difficulty in movement. Maximum bone density occurs by the mid- to late thirties, from which point there is a progressive loss of bone. The rate of this bone loss begins slowly but accelerates during the fifties (Baron, 2012). Women lose bone mass about twice as quickly as men. By the end of midlife, bones break more easily and heal more slowly (Gulsahi, 2015).Vision and Hearing Accommodation of the eye—the ability to focus and maintain an image on the retina—declines sharply between 40 and 59 years of age. In particular, middle-aged individuals begin to have difficulty viewing close objects, which means that many individuals have to wear glasses with bifocal lenses—lenses with two sections that enable the wearer to see items at different distances (Schieber, 2006). Also, there is some evidence that the retina becomes less sensitive to low levels of illumination. Laser surgery and implantation of intraocular lenses have become routine procedures for correcting vision in middle-aged adults (Fang, Wang, & He, 2013). Hearing also can start to decline by the age of 40 (Roring, Hines, & Charness, 2007). Sensitivity to high pitches usually declines first. The ability to hear low-pitched sounds does not seem to decline much in middle adulthood, though. Men usually lose their sensitivity to high-pitched sounds sooner than women do. However, this gender difference might be due to men's greater exposure to noise in occupations such as mining, automobile work, and so on (Scialfa & Kline, 2007). Also, recent advances in the effectiveness of hearing aids are dramatically improving the hearing of many aging adults (Banerjee, 2011). However, even with the advent of technologically sophisticated hearing devices, many people don't always wear them, or wear them inappropriately.Cardiovascular System Midlife is the time when high blood pressure and high cholesterol take many individuals by surprise (Wu & others, 2016). Cardiovascular disease increases considerably in middle age (Hulsegge & others, 2016; Wu & others, 2016). The level of cholesterol in the blood increases through the adult years and in midlife begins to accumulate on the artery walls, increasing the risk of cardiovascular disease (Choi & Lee, 2016; Hasvold & others, 2016). High blood pressure (hypertension), too, often occurs in the forties and fifties (Kitaoka & others, 2016). One study found that uncontrolled hypertension can damage the brain's structure and function as early as the late thirties and early forties (Maillard & others, 2012). Another study revealed that hypertension in middle age was linked to risk of cognitive impairment in late adulthood (23 years later) (Virta & others, 2013). Exercise, weight control, and a diet rich in fruits, vegetables, and whole grains can often help to stave off many cardiovascular problems in middle Page 341 age (Atashak, Stannard, & Azizheigi, 2016; Niu & others, 2016; Sallam & Laher, 2016). In a recent study, a high level of physical activity was associated with a lower risk of cardiovascular disease in the three weight categories studied (normal, overweight, and obese) (Carlsson & others, 2016). Also, in a recent study, middle-aged adults who had exercised regularly during adolescence were less likely to develop cardiovascular disease (Nechuta & others, 2015). A recent national study confirmed that moderate-to-vigorous physical activity (such as running, swimming, bicycling) on a regular basis was linked to reduced rates of all-cause mortality, especially for men (Loprinzi, 2015). Another recent study found that having an unhealthy diet was a strong predictor of cardiovascular disease (Menotti & others, 2015). Also, although heredity influences cholesterol levels, LDL (the bad cholesterol) can be reduced and HDL (the good cholesterol) increased by eating food that is very low in saturated fat and cholesterol and by exercising regularly (Koba & others, 2016). Further, the health benefits of cholesterol-lowering and hypertension-lowering drugs are a major factor in improving the health of many middle-aged adults and increasing their life expectancy (Wenger & others, 2014; Yusuf & others, 2016).Lungs There is little change in lung capacity through most of middle adulthood. However, at about the age of 55, the proteins in lung tissue become less elastic. This change, combined with a gradual stiffening of connective tissues in the chest wall, decreases the lungs' capacity to shuttle oxygen from the air people breathe to the blood in their veins. The lung capacity of individuals who are smokers drops precipitously in middle age, but if the individuals quit smoking their lung capacity improves, although not to the level of individuals who have never smoked. Recent research also has found that low cognitive ability in early adulthood is linked to reduced lung functioning in middle age (Carroll & others, 2011). Exercise is linked to better lung functioning and a lower risk of developing lung cancer (Strookappe & others, 2015). In a recent study, more than 17,000 men were given a cardiovascular fitness assessment at 50 years of age (Lakoski & others, 2013). Subsequent analysis of Medicare claims and deaths found that the risk of being diagnosed with lung cancer was reduced by 68 percent for men who were the most fit compared with those who were the least fit. Sleep Some aspects of sleep become more problematic in middle age (Green & others, 2012; Prairie & others, 2015). The total number of hours slept usually remains the same as in early adulthood, but beginning in the forties, wakeful periods are more frequent and there is less of the deepest type of sleep (stage 4). The amount of time spent lying awake in bed at night begins to increase in middle age, and this can produce a feeling of being less rested in the morning (Abbott, 2003). Sleep-disordered breathing and restless legs syndrome become more prevalent in middle age (Polo-Kantola, 2011). One study found that middle-aged adults who sleep less than six hours a night on average had an increased risk of developing stroke symptoms (Ruiter & others, 2012). Another study revealed that sleep deprivation was associated with less effective immune system functioning (Wilder-Smith & others, 2013). Also, a recent study revealed that poor sleep quality in middle adulthood was linked to cognitive decline (Waller & others, 2016), and a research review concluded that sleep deprivation is linked to problems with long-term memory consolidation (Abel & others, 2013). And a recent Korean study found that these factors were linked to sleep problems in middle age: unemployment, being unmarried, currently being a smoker, lack of exercise, having irregular meals, and frequently experiencing stressful events (Yoon & others, 2015).

fluid intelligence

whereas fluid intelligence, one's ability to reason abstractly, begins to decline during middle adulthood (see Figure 1).