Conceptions of Age

Lifespan vs. Life expectancy

At this point you must be wondering what the difference between lifespan and life expectancy is, according to developmentalists. Lifespan, or longevity, refers to the maximum age any member of a species can reach under optimal conditions. For instance, the grey wolf can live up to 20 years in captivity, the bald eagle up to 50 years, and the Galapagos tortoise over 150 years (Smithsonian National Zoo, 2016). The longest recorded lifespan for a human was Jean Calment who died in 1994 at the age of 122 years, 5 months, and 14 days (Guinness World Records, 2016). Life expectancy is the average number of years a person born in a particular time period can typically expect to live (Vogt & Johnson, 2016).

How old are you?

Chances are you would answer that question based on the number of years since your birth, or what is called your chronological age. Ever felt older than your chronological age? Some days we might “feel” like we are older, especially if we are not feeling well, are tired, or are stressed out. We might notice that a peer seems more emotionally mature than we are, or that they are physically more capable. So years since birth is not the only way we can conceptualize age.

Biological age

Another way developmental researchers can think about the concept of age is to examine how quickly the body is aging, this is your biological age. Several factors determine the rate at which our body ages. Our nutrition, level of physical activity, sleeping habits, smoking, alcohol consumption, how we mentally handle stress, and the genetic history of our ancestors, to name but a few.

Psychological age

Our psychologically adaptive capacity compared to others of our chronological age is our psychological age. This includes our cognitive capacity along with our emotional beliefs about how old we are. An individual who has cognitive impairments might be 20 years of age, yet has the mental capacity of an 8-year-old. A 70- year-old might be travelling to new countries, taking courses at college, or starting a new business. Compared to others of our age group, we may be more or less active and excited to meet new challenges. Remember you are as young or old as you feel.

Social age

Our social age is based on the social norms of our culture and the expectations our culture has for people of our age group. Our culture often reminds us whether we are “on target” or “off target” for reaching certain social milestones, such as completing our education, moving away from home, having children, or retiring from work. However, there have been arguments that social age is becoming less relevant in the 21st century (Neugarten, 1979; 1996). If you look around at your fellow students at college you might notice more people who are older than traditional aged college students, those 18 to 25. Similarly, the age at which people are moving away from the home of their parents, starting their careers, getting married or having children, or even whether they get married or have children at all, is changing.

Those who study lifespan development recognize that chronological age does not completely capture a person’s age. Our age profile is much more complex than this. A person may be physically more competent than others in their age group, while being psychologically immature. So, how old are you?

Periods of Human Development

Think about the lifespan and make a list of what you would consider the basic periods of development. How many periods or stages are on your list? Perhaps you have three: childhood, adulthood, and old age. Or maybe four: infancy, childhood, adolescence, and adulthood. Developmentalists often break the lifespan into eight stages, described in Table 1.2.

Table 1.2 Age Periods of Development

adapted from Lally & Valentine-French, 2019

In addition, the topic of “Death and Dying” is usually addressed after late adulthood since overall, the likelihood of dying increases in later life (though individual and group variations exist). Death and dying will be the topic of our last module, though it is not necessarily a stage of development that occurs at a particular age.

Table 1.2 shows the developmental periods that will be explored in this book, starting with prenatal development and continuing thought late adulthood. Both childhood and adulthood are divided into multiple developmental periods. 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, even though both are considered adults.

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

The first 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

This period is also referred to as the preschool years and consists of the years that follow toddlerhood and precede formal schooling. As a two to six-year-old, the child is busy learning language, gaining a sense of self and greater independence, and  beginning to understand the workings of the physical world.

Middle and Late Childhood

The ages of six to the onset of puberty comprise middle and late 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 assessing one’s abilities and accomplishments by making comparisons between self and others.

Adolescence

Adolescence is a period of dramatic physical change marked by an overall 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. At the same time, adolescents have a sense of invincibility that puts them at greater risk of accidents or contracting sexually transmitted infections that can have lifelong consequences.

Emerging Adulthood

The period of emerging adulthood is a transitional time between the end of adolescence and before individuals acquire all the benchmarks of adulthood. Continued identity exploration and preparation for full independence from parents are negotiated. Although at one’s physiological peak, emerging adults are most at risk for involvement in violent crimes and substance abuse.

Early Adulthood

The twenties and thirties are identified as early adulthood. Intimate relationships, establishing families (of all shapes and sizes), and work are primary concerns at this stage of life. For adults with children, developmental changes can become organized around the family life cycle.

Middle Adulthood

The forties through the mid-sixties are referred to as middle adulthood. This is a period in which aging becomes more noticeable and when many people are at their peak of productivity in love and work. At this age, some people are negotiating adolescent children and aging parents at the same time.

Late Adulthood

Late adulthood is sometimes subdivided into two categories: The young-old who are from 65-84 years and the oldest-old who are 85 years and older. One of the primary differences between these groups is that the young-old are still relatively healthy, productive, active, and the majority continue to live independently. With both age groups the risks of diseases such as arteriosclerosis, cancer, and cerebral vascular disease increase substantially.

Death and Dying

The study of death and dying 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. Factors such as age, religion, and culture play important roles in attitudes and approaches to death and dying. The most common causes of death vary with age, gender, race, culture, and time in history. Dying and grieving are processes and may share certain stages of reactions to loss.