Physical Development in Adulthood

1. Developmental Milestones Adulthood

As individuals move through early and middle adulthood, a variety of physical changes take place in the body.

Learning Objectives

Review the milestones of physical development in early and middle adulthood

Developmental Milestones for Typical High-Schoolers. Into high-schoolers who start looking and thinking more like adults with the skills to envision the future.

Key Takeaways

Key Points

Developmental Milestones Adulthood

• Adults experiences age-related changes based on many factors: biological factors such as molecular and cellular changes are called primary aging, while aging that occurs due to controllable factors, such as lack of physical exercise and poor diet, is called secondary aging.
• In early adulthood (ages 20–40), our physical abilities are at their peak, including muscle strength, reaction time, sensory abilities, and cardiac functioning.
• The aging process also begins during early adulthood and is characterized by changes in skin, vision, and reproductive capability.
• Aging speeds up during middle adulthood (ages 40–65) and is characterized by decline in vision, hearing, and immune-system functioning, as well as the end of reproductive capability for women, known as menopause.

Key Terms

• glaucoma: An eye disease or disorder of the optic nerve that, if untreated, may lead to damage to the optic disc of the eye and resultant visual-field loss, which can lead to blindness.
• menopause: The ending of menstruation; the time in a woman’s life when this happens.
• presbyopia: Inability of the eye, due to aging, to focus on nearby objects; farsightedness.

As we age, our bodies change in physical ways. One can expect a variety of changes to take place through the early- and middle-adult years. Each person experiences age-related changes based on many factors: biological factors such as molecular and cellular changes are called primary aging, while aging that occurs due to controllable factors, such as lack of physical exercise and poor diet, is called secondary aging.

Aging factors: As an individual progresses through adulthood, a variety of factors can affect the aging process. This includes primary factors like decline of cellular function and oxidative damage, and secondary factors like an unhealthy lifestyle.

Early Adulthood (Ages 20–40)

By the time we reach early adulthood, our physical maturation is complete, although our height and weight may increase slightly. In early adulthood, our physical abilities are at their peak, including muscle strength, reaction time, sensory abilities, and cardiac functioning. Most professional athletes are at the top of their game during this stage, and many women have children in the early-adulthood years.

The aging process, although not overt, begins during early adulthood. Around the age of 30, many changes begin to occur in different parts of the body. For example, the lens of the eye starts to stiffen and thicken, resulting in changes in vision (usually affecting the ability to focus on close objects). Sensitivity to sound decreases; this happens twice as quickly for men as for women. Hair can start to thin and become gray around the age of 35, although this may happen earlier for some individuals and later for others. The skin becomes drier and wrinkles start to appear by the end of early adulthood. The immune system becomes less adept at fighting off illness, and reproductive capacity starts to decline.

Middle Adulthood (Ages 40–65)

During middle adulthood, the aging process becomes more apparent. Around the age of 60, the eyes lose their ability to adjust to objects at varying distances, known as presbyopia. Most people between the ages of 40 and 60 will need some form of corrective lenses for vision deficits. Middle-aged adults are also at higher risk than younger adults for certain eye problems, such as glaucoma. Hearing also further declines: 14 percent of middle-aged Americans have hearing problems. Skin continues to dry out and is prone to more wrinkling, particularly on the sensitive face area. Age spots and blood vessels become more apparent as the skin continues to dry and get thinner. The muscle-to-fat ratio for both men and women also changes throughout middle adulthood, with an accumulation of fat in the stomach area.

Women experience a gradual decline in fertility as they approach the onset of menopause—the end of the menstrual cycle—around 50 years old. This process involves hormonal changes and may last anywhere from six months to five years. Because of the shifting hormone levels, women going through menopause often experience a range of other symptoms, such as anxiety, poor memory, inability to concentrate, depressive mood, irritability, mood swings, and less interest in sexual activity.

Cognitive Development in Adulthood

Cognition changes over a person’s lifespan, peaking at around age 35 and slowly declining in later adulthood.

Learning Objectives

Review the milestones of cognitive development in early and middle adulthood

Key Takeaways

Key Points

• Unlike our physical abilities, which peak in our mid-20s and then begin a slow decline, our cognitive abilities remain relatively steady throughout early and middle adulthood.
• Since Piaget’s theory of cognitive development, other developmental psychologists have suggested a fifth stage of cognitive development, known as postformal operational thinking.
• Early adulthood is a time of relativistic thinking, in which young people begin to become aware of more complexities in life.
• Two forms of intelligence —crystallized and fluid—are the main focus of middle adulthood. While crystallized intelligence grows steadily, fluid intelligence starts to decline even prior to mid-adulthood.

Key Terms

• dialectic: Any formal system of reasoning that arrives at a truth by the exchange of logical arguments; a contradiction of ideas that serves as the determining factor in their interaction.
• constructive: Carefully considered and meant to be helpful.
• contradiction: A logical incompatibility among two or more elements or propositions.

Because we spend so many years in adulthood (more than any other stage), cognitive changes are numerous during this period. In fact, research suggests that adult cognitive development is a complex, ever-changing process that may be even more active than cognitive development in infancy and early childhood (Fischer, Yan, & Stewart, 2003).

Unlike our physical abilities, which peak in our mid-20s and then begin a slow decline, our cognitive abilities remain relatively steady throughout early and middle adulthood. Research has found that adults who engage in mentally and physically stimulating activities experience less cognitive decline in later adult years and have a reduced incidence of mild cognitive impairment and dementia (Hertzog, Kramer, Wilson, & Lindenberger, 2009; Larson et al., 2006; Podewils et al., 2005).

Beyond Piaget’s Theory

According to Jean Piaget’s theory of cognitive development, the establishment of formal operational thinking occurs during early adolescence and continues through adulthood. Unlike earlier concrete thinking, this kind of thinking is characterized by the ability to think in abstract ways, engage in deductive reasoning, and create hypothetical ideas to explain various concepts.

Since Piaget’s theory, other developmental psychologists have suggested a fifth stage of cognitive development, known as postformal operational thinking (Basseches, 1984; Commons & Bresette, 2006; Sinnott, 1998). In postformal thinking, decisions are made based on situations and circumstances, and logic is integrated with emotion as adults develop principles that depend on contexts. This kind of thinking includes the ability to think in dialectics, and differentiates between the ways in which adults and adolescents are able to cognitively handle emotionally charged situations.

Early Adulthood

During early adulthood, cognition begins to stabilize, reaching a peak around the age of 35. Early adulthood is a time of relativistic thinking, in which young people begin to become aware of more than simplistic views of right vs. wrong. They begin to look at ideas and concepts from multiple angles and understand that a question can have more than one right (or wrong) answer. The need for specialization results in pragmatic thinking—using logic to solve real-world problems while accepting contradiction, imperfection, and other issues. Finally, young adults develop a sort of expertise in either education or career, which further enhances problem-solving skills and the capacity for creativity.

Intelligence: Cognitive ability changes over the course of a person’s lifespan, but keeping the mind engaged and active is the best way to keep thinking sharp.

Middle Adulthood

Two forms of intelligence—crystallized and fluid—are the main focus of middle adulthood. Our crystallized intelligence is dependent upon accumulated knowledge and experience—it is the information, skills, and strategies we have gathered throughout our lifetime. This kind of intelligence tends to hold steady as we age—in fact, it may even improve. For example, adults show relatively stable to increasing scores on intelligence tests until their mid-30s to mid-50s (Bayley & Oden, 1955). Fluid intelligence, on the other hand, is more dependent on basic information-processing skills and starts to decline even prior to middle adulthood. Cognitive processing speed slows down during this stage of life, as does the ability to solve problems and divide attention. However, practical problem-solving skills tend to increase. These skills are necessary to solve real-world problems and figure out how to best achieve a desired goal.

Socioemotional Development in Adulthood

Early and middle adulthood is influenced by a number of social and emotional factors, such as work and interpersonal relationships.

Learning Objectives

Review the milestones and crises of socioemotional development in early and middle adulthood

Key Takeaways

Key Points

• There are many social and emotional factors that influence aging. For those in early and middle adulthood, meaning is often found through work and family life—two areas that correspond with Erik Erikson’s psychosocial theory of development.
• According to Erikson, intimacy vs. isolation is a stage of psychosocial development in which people face the crisis of being alone versus being involved in meaningful relationships.
• Positive relationships with significant others in our adult years have been found to contribute to a state of well-being.
• Erikson’s stage of generativity vs. stagnation revolves around a person’s sense of their contribution to the world.
• Central tasks during middle adulthood can include maintaining healthy life patterns, raising children or in some way helping future generations, being proud of one’s accomplishments, or taking care of aging parents.

Key Terms

• generativity: Contributing to the development of others and of future generations; productivity and creativity; the act of helping society move forward.

Social and Emotional Aspects of Adulthood

There are many theories about the social and emotional aspects of aging. Some aspects of healthy aging include activities, social connectedness, and the role of a person’s culture. According to many theorists, including George Vaillant (2002), who studied and analyzed over 50 years of data, we need to have and continue to find meaning throughout our lives.

For those in early and middle adulthood, meaning is often found through work (Sterns & Huyck, 2001) and family life (Markus, Ryff, Curan, & Palmersheim, 2004). These areas relate to the tasks that Erik Erikson referred to as generativity vs. stagnation and intimacy vs. isolation.

Relationships in Adulthood

Positive relationships with significant others in our adult years have been found to contribute to a state of well-being (Ryff & Singer, 2009). Most adults in the United States identify themselves through their relationships with family—particularly with spouses, children, and parents (Markus et al., 2004). While raising children can be stressful, especially when they are young, research suggests that parents reap the rewards down the road, as adult children tend to have a positive effect on parental well-being (Umberson, Pudrovska, & Reczek, 2010). Having stable intimate relationships has also been found to contribute to well-being throughout adulthood (Vaillant, 2002).

A lack of positive and meaningful relationships during adulthood can result in what Erikson termed the crisis of intimacy vs. isolation in his theory of psychosocial development. In young adulthood (i.e., 20s and early 30s), people tend to be concerned with forming meaningful relationships; young and middle-aged adults are subject to loneliness if they are unable to form meaningful relationships with family, friends, or community.

Social relationships in adulthood: Social relationships are important to overall well-being in early and middle adulthood. (credit: Philippe Put)

Crises of Adulthood

Both early and middle adulthood come with particular challenges; these challenges are at times referred to as “quarter-life crises” and ” mid-life crises,” respectively. A quarter-life crisis typically occurs between the ages of 25 and 30. It often revolves around the challenges that arise from young adults newly living life on their own and feeling overwhelmed with new responsibilities; it can also happen after the birth of a child or if a person graduates from college and cannot find a job in their chosen field. In this stage of life, young people may worry about their future, wonder if they’ve made poor choices, or wonder what life might hold for them now.

The main triggers for a mid-life crisis include problems with work, trouble in a marriage, children growing up and leaving the home, or the aging or death of a person’s parents. This is likely to occur during Erikson’s stage of generativity vs. stagnation, a time when people think about the contribution they are making to the world. Generativity involves finding one’s life’s work and contributing to the development of others through activities such as volunteering, mentoring, and raising children; those who do not master this task may experience a feeling of stagnation.

Individuals having a mid-life crisis may experience some of the following:

• a search for an undefined dream or goal;
• a deep sense of regret for goals not accomplished;
• a fear of humiliation among more successful colleagues;
• a desire to achieve a feeling of youthfulness;
• a need to spend more time alone or with certain peers.

Some who experience a quarter- or mid-life crisis struggle with how to cope and may engage in harmful behaviors, such as abuse of alcohol or drugs or excessive spending of money. Others may experiment with different aspects of their personality, explore new hobbies, or otherwise seek out change in their lives.

Finding Meaning Through Work

Many adults find meaning in and define themselves by what they do—their careers. Earnings peak for many during adulthood, yet research has found that job satisfaction is more closely tied to work that involves contact with other people, is interesting, provides opportunities for advancement, and allows some independence (Mohr & Zoghi, 2006) than it is to salary (Iyengar, Wells, & Schwartz, 2006).

Erikson’s stage of generativity vs. stagnation revolves around a person’s sense of their contribution to the world. Generativity is about making life productive and creative so that it matters to others, especially those in the next generation. According to Erikson, a person who is self-centered and unable or unwilling to help society move forward develops a feeling of stagnation—a dissatisfaction with the relative lack of productivity. The central tasks during middle adulthood can include expressing love through more than sexual contacts, maintaining healthy life patterns, helping growing and grown children to be responsible adults, relinquishing a central role in the lives of grown children, creating a comfortable home, being proud of one’s accomplishments, taking care of aging parents, adjusting to the physical changes of middle age, and using leisure time creatively.

Relationships and Families in Adulthood

Several theories examine how interpersonal relationships form and develop during adulthood.

Learning Objectives

Summarize Levinger’s and Knapp’s theories of relational development in adulthood

Key Takeaways

Key Points

• An interpersonal relationship is a strong, deep, or close association or acquaintanceship between two or more people that may range from brief to enduring in duration.
• Interpersonal relationships are dynamic systems that change continuously during their existence. Like living organisms, relationships have a beginning, a lifespan, and an end.
• One of the most influential models of relationship development was proposed by psychologist George Levinger. His model consists of five stages: acquaintanceship, buildup, continuation, deterioration, and termination.
• M. L. Knapp developed a model of relational development, consisting of two main stages: the coming-together stage and coming-apart stage.
• Coming together consists of five phases—initiating, experimentation, intensifying, integration, and bonding. Similarly, coming apart consists of differentiating, circumscribing, stagnation, avoidance, and termination.

Key Terms

• interpersonal: Existing between two or more people.
• heterosexual: Sexually attracted to members of the opposite sex.

Interpersonal Relationships in Adulthood

Positive relationships with significant others in our adult years have been found to contribute to a state of well-being (Ryff & Singer, 2009). Most adults in the United States identify themselves through their relationships with family—particularly with spouses, children, and parents. An interpersonal relationship is a strong, deep, or close association or acquaintanceship between two or more people that may range from brief to enduring in duration. Like people, relationships change and grow; they may either improve or dissipate over time. The association between two people can be based on various factors—love, solidarity, business, or any other context that requires two (or more) people to interact.

A Nepali Hindu couple in a marriage ceremony: Interpersonal relationships take many forms in many different cultures.

Interpersonal relationships are dynamic systems that change continuously during their existence. Like living organisms, relationships have a beginning, a lifespan, and an end. They tend to grow and improve gradually as people get to know each other and become closer emotionally, or they gradually deteriorate as people drift apart.

Levinger’s Model of Relationships

One of the most influential models of relationship development was proposed by psychologist George Levinger. This model was formulated to describe heterosexual, adult romantic relationships, but it has been applied to other kinds of interpersonal relationships since then. According to the model, the natural development of a relationship follows five stages:

1. Acquaintance and Acquaintanceship: Becoming acquainted depends on previous relationships, physical proximity, first impressions, and a variety of other factors. If two people begin to like each other, continued interactions may lead to the next stage, but acquaintance can continue indefinitely. Another example is association.
2. Buildup: During this stage, people begin to trust and care about each other. The need for intimacy, compatibility, and such filtering agents as common background and goals will influence whether or not interaction continues.
3. Continuation: This stage follows a mutual commitment to strong and close long-term friendships, romantic relationship, or even marriage. It is generally a long, relatively stable period. Nevertheless, continued growth and development will occur during this time. Mutual trust is important for sustaining the relationship.
4. Deterioration: Not all relationships deteriorate, but those that do tend to show signs of trouble. Boredom, resentment, and dissatisfaction may occur. Individuals may communicate less and avoid self-disclosure. Loss of trust and betrayals may take place as the downward spiral continues, eventually ending the relationship. Alternately, the participants may find some way to resolve the problems and reestablish trust.
5. Termination: The final stage marks the end of the relationship, either by breakup, death, or spatial separation and severing all existing ties of either friendship or romantic love.

Knapp’s Theory of Relational Development

Another theory, developed by M. L. Knapp, is known as the model of relational development. This theory consists of two main stages, each with several parts. The first stage is known as the coming together phase, and the second stage is known as the coming apart phase.

Coming Together

Coming together consists of five phases—initiating, experimentation, intensifying, integration, and bonding.

1. During initiating, first impressions are made; physical factors play a large role in this phase. People often want to portray themselves as easy to talk to, friendly, and open to discussion. This phase tends to be superficial as people are trying to make a good first impression.
2. During experimentation, the two people attempt to find some common ground between each other’s lives, such as common interests and hobbies. People start to open up more and ask more personal questions as they get to know one another.
3. During the intensifying phase, people open themselves up fully in the hope of being accepted by the potential mate. During this phase, people may reveal secrets about themselves or others in order to test the trust level of potential partners.
4. The integration phase involves people merging their lives together and solidifying a relationship status.
5. Finally, during the bonding phase, people recognize a commitment to one another (traditionally through marriage, though many alternative forms of commitment exist) and the relationship lasts until death, breakup, or divorce.

Coming Apart

Coming apart consists of five stages as well—differentiating, circumscribing, stagnation, avoidance, and termination.

1. Differentiation involves focusing more on differences rather than similarities. This can lead to an increasing emotional distance between the parties involved.
2. During circumscribing, the primary focus of the relationship shifts from differences to setting limits and boundaries on communication between the two people. This further pushes two people apart.
3. Stagnation is when two people have reached a “stand-off” phase—nothing changes and neither party is willing to change.
4. Avoidance occurs when people engage in limited communication and take steps to distance themselves from one another.
5. Finally, during termination, the relationship is ended.

Think about the life span and make a list of what you would consider the periods of development. How many stages are on your list? Perhaps you have three: childhood, adulthood, and old age. Or maybe four: infancy, childhood, adolescence, and adulthood. Developmentalists break the life span into nine stages as follows:

• Prenatal Development
• Infancy and Toddlerhood
• Early Childhood
• Middle Childhood
• Adolescence
• Early Adulthood
• Middle Adulthood
• Late Adulthood
• Death and Dying

This list reflects unique aspects of the various stages of childhood and adulthood that will be explored in this book. So while both an 8 month old and an 8 year old are considered children, they have very different motor abilities, social relationships, and cognitive skills. Their nutritional needs are different and their primary psychological concerns are also distinctive. The same is true of an 18 year old and an 80 year old, both considered adults. We will discover the distinctions between being 28 or 48 as well. But first, here is a brief overview of the stages.

Prenatal Development

Conception occurs and development begins. All of the major structures of the body are forming and the health of the mother is of primary concern. Understanding nutrition, teratogens (or environmental factors that can lead to birth defects), and labor and delivery are primary concerns.

Infancy and Toddlerhood

Newborn photo courtesy Fenja2

The first year and a half to two years of life are ones of dramatic growth and change. A newborn, with a keen sense of hearing but very poor vision is transformed into a walking, talking toddler within a relatively short period of time. Caregivers are also transformed from someone who manages feeding and sleep schedules to a constantly moving guide and safety inspector for a mobile, energetic child.

Early Childhood

Early childhood is also referred to as the preschool years consisting of the years which follow toddlerhood and precede formal schooling. As a three to five-year-old, the child is busy learning language, is gaining a sense of self and greater independence, and is beginning to learn the workings of the physical world. This knowledge does not come quickly, however, and preschoolers may have initially have interesting conceptions of size, time, space and distance such as fearing that they may go down the drain if they sit at the front of the bathtub or by demonstrating how long something will take by holding out their two index fingers several inches apart. A toddler’s fierce determination to do something may give way to a four-year-old’s sense of guilt for doing something that brings the disapproval of others.

Middle Childhood

Photo Courtesy Pink Sip

The ages of six through eleven comprise middle childhood and much of what children experience at this age is connected to their involvement in the early grades of school. Now the world becomes one of learning and testing new academic skills and by assessing one’s abilities and accomplishments by making comparisons between self and others. Schools compare students and make these comparisons public through team sports, test scores, and other forms of recognition. Growth rates slow down and children are able to refine their motor skills at this point in life. And children begin to learn about social relationships beyond the family through interaction with friends and fellow students.

Adolescence

Adolescence is a period of dramatic physical change marked by an overall physical growth spurt and sexual maturation, known as puberty. It is also a time of cognitive change as the adolescent begins to think of new possibilities and to consider abstract concepts such as love, fear, and freedom. Ironically, adolescents have a sense of invincibility that puts them at greater risk of dying from accidents or contracting sexually transmitted infections that can have lifelong consequences.

Early Adulthood

Photo Courtesy Josh Gray

The twenties and thirties are often thought of as early adulthood. (Students who are in their mid 30s tend to love to hear that they are a young adult!). It is a time when we are at our physiological peak but are most at risk for involvement in violent crimes and substance abuse. It is a time of focusing on the future and putting a lot of energy into making choices that will help one earn the status of a full adult in the eyes of others. Love and work are primary concerns at this stage of life.

Middle Adulthood

The late thirties through the mid-sixties is referred to as middle adulthood. This is a period in which aging, that began earlier, becomes more noticeable and a period at which many people are at their peak of productivity in love and work. It may be a period of gaining expertise in certain fields and being able to understand problems and find solutions with greater efficiency than before. It can also be a time of becoming more realistic about possibilities in life previously considered; of recognizing the difference between what is possible and what is likely. This is also the age group hardest hit by the AIDS epidemic in Africa resulting in a substantial decrease in the number of workers in those economies (Weitz, 2007).

Late Adulthood

Photo Courtesy Overstreet

This period of the life span has increased in the last 100 years, particularly in industrialized countries. Late adulthood is sometimes subdivided into two or three categories such as the “young old” and “old old” or the “young old”, “old old”, and “oldest old”. We will follow the former categorization and make the distinction between the “young old” who are people between 65 and 79 and the “old old” or those who are 80 and older. One of the primary differences between these groups is that the young old are very similar to midlife adults; still working, still relatively healthy, and still interested in being productive and active. The “old old” remain productive and active and the majority continues to live independently, but risks of the diseases of old age such as arteriosclerosis, cancer, and cerebral vascular disease increases substantially for this age group. Issues of housing, healthcare, and extending active life expectancy are only a few of the topics of concern for this age group. A better way to appreciate the diversity of people in late adulthood is to go beyond chronological age and examine whether a person is experiencing optimal aging (like the gentleman pictured above who is in very good health for his age and continues to have an active, stimulating life), normal aging (in which the changes are similar to most of those of the same age), or impaired aging (referring to someone who has more physical challenge and disease than others of the same age).

Death and Dying

This topic is seldom given the amount of coverage it deserves. Of course, there is a certain discomfort in thinking about death but there is also a certain confidence and acceptance that can come from studying death and dying. We will be examining the physical, psychological and social aspects of death, exploring grief or bereavement, and addressing ways in which helping professionals work in death and dying. And we will discuss cultural variations in mourning, burial, and grief.