CHAPTER 5

DEVELOPING THROUGH THE LIFE SPAN

Developmental Issues, Prenatal Development, and the Newborn

5-1 What three issues have engaged developmental psychologists?

Developmental psychologists study physical, mental, and social changes throughout the life span. They focus on three issues: nature and nurture (the interaction between our genetic inheritance and our experiences); continuity and stages (whether development is gradual and continuous or a series of relatively abrupt changes); and stability and change (whether our traits endure or change as we age).

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5-2 What is the course of prenatal development, and how do teratogens affect that development?

The life cycle begins at conception, when one sperm cell unites with an egg to form a zygote. The zygote’s inner cells become the embryo, and the outer cells become the placenta. In the next 6 weeks, body organs begin to form and function, and by 9 weeks, the fetus is recognizably human.

Teratogens are potentially harmful agents that can pass through the placental screen and harm the developing embryo or fetus, as happens with fetal alcohol syndrome.

5-3 What are some newborn abilities, and how do researchers explore infants’ mental abilities?

Babies are born with sensory equipment and reflexes that facilitate their survival and their social interactions with adults. For example, they quickly learn to discriminate their mother’s smell and sound. Researchers use techniques that test habituation, such as the novelty-preference procedure, to explore infants’ abilities.

Infancy and Childhood

5-4 During infancy and childhood, how do the brain and motor skills develop?

The brain’s nerve cells are sculpted by heredity and experience. As a child’s brain develops, neural connections grow more numerous and complex. Experiences then trigger a pruning process, in which unused connections weaken and heavily used ones strengthen. This process continues until puberty. Early childhood is an important period for shaping the brain, but our brain modifies itself in response to our learning throughout life. In childhood, complex motor skills—sitting, standing, walking—develop in a predictable sequence, though the timing of that sequence is a function of individual maturation and culture. We have no conscious memories of events occurring before about age 3¹/₂. This infantile amnesia occurs in part because major brain areas have not yet matured.

5-5 From the perspectives of Piaget, Vygotsky, and today’s researchers, how does a child’s mind develop?

In his theory of cognitive development, Jean Piaget proposed that children actively construct and modify their understanding of the world through the processes of assimilation and accommodation. They form schemas that help them organize their experiences. Progressing from the simplicity of the sensorimotor stage of the first two years, in which they develop object permanence, children move to more complex ways of thinking. In the preoperational stage (about age 2 to about 6 or 7), they develop a theory of mind. In the preoperational stage, children are egocentric and unable to perform simple logical operations. At about age 7, they enter the concrete operational stage and are able to comprehend the principle of conservation. By about age 12, children enter the formal operational stage and can reason systematically.

Research supports the sequence Piaget proposed, but it also shows that young children are more capable, and their development more continuous, than he believed.

Lev Vygotsky’s studies of child development focused on the ways a child’s mind grows by interacting with the social environment. In his view, parents and caretakers provide temporary scaffolds enabling children to step to higher levels of learning.

5-6 What is autism spectrum disorder?

Autism spectrum disorder (ASD) is a disorder marked by social deficiencies and repetitive behaviors. By age 8, 1 in 68 U.S. children now gets diagnosed with ASD, though the reported rates vary by place. The increase in ASD diagnoses has been offset by a decrease in the number of children with a “cognitive disability” or “learning disability,” suggesting a relabeling of children’s disorders.

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5-7 How do parent-infant attachment bonds form?

At about 8 months, soon after object permanence develops, children separated from their caregivers display stranger anxiety. Infants form attachments not simply because parents gratify biological needs but, more important, because they are comfortable, familiar, and responsive. Many birds and other animals have a more rigid attachment process, called imprinting, that occurs during a critical period.

5-8 How have psychologists studied attachment differences, and what have they learned?

Attachment has been studied in strange situation experiments, which show that some children are securely attached and others are insecurely attached. Infants’ differing attachment styles reflect both their individual temperament and the responsiveness of their parents and child-care providers. Adult relationships seem to reflect the attachment styles of early childhood, lending support to Erik Erikson’s idea that basic trust is formed in infancy by our experiences with responsive caregivers.

5-9 How does childhood neglect or abuse affect children’s attachments?

Children are very resilient, but those who are severely neglected by their parents, or otherwise prevented from forming attachments at an early age, may be at risk for attachment problems.

5-10 How do children’s self-concepts develop?

Self-concept, an understanding and evaluation of who we are, emerges gradually. By 15 to 18 months, children recognize themselves in a mirror. By school age, they can describe many of their own traits, and by age 8 or 10 their self-image is stable.

5-11 What are three parenting styles, and how do children’s traits relate to them?

Parenting styles—authoritarian, permissive, and authoritative—reflect varying degrees of control. Children with high self-esteem tend to have authoritative parents and to be self-reliant and socially competent, but the direction of cause and effect in this relationship is not clear. Child-raising practices reflect both individual and cultural values.

Adolescence

5-12 How is adolescence defined, and how do physical changes affect developing teens?

Adolescence is the transition period from childhood to adulthood, extending from puberty to social independence. Boys seem to benefit (though with risks) from “early” maturation, girls from “late” maturation. The brain’s frontal lobes mature and myelin growth increases during adolescence and the early twenties, enabling improved judgment, impulse control, and long-term planning.

5-13 How did Piaget, Kohlberg, and later researchers describe adolescent cognitive and moral development?

Piaget theorized that adolescents develop a capacity for formal operations and that this development is the foundation for moral judgment. Lawrence Kohlberg proposed a stage theory of moral reasoning, from a preconventional morality of self-interest, to a conventional morality concerned with upholding laws and social rules, to (in some people) a postconventional morality of universal ethical principles. Other researchers believe that morality lies in moral intuition and moral action as well as thinking. Some critics argue that Kohlberg’s postconventional level represents morality from the perspective of individualist, middle-class people.

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5-14 What are the social tasks and challenges of adolescence?

Erikson theorized that each life stage has its own psychosocial task, and that a chief task of adolescence is solidifying one’s sense of self—one’s identity. This often means trying out a number of different roles. Social identity is the part of the self-concept that comes from a person’s group memberships.

5-15 How do parents and peers influence adolescents?

During adolescence, parental influence diminishes and peer influence increases, in part because of the selection effect—the tendency to choose similar others. But adolescents also do adopt their peers’ ways of dressing, acting, and communicating. Parents have more influence in religion, politics, and college and career choices.

5-16 What is emerging adulthood?

The transition from adolescence to adulthood is now taking longer. Emerging adulthood is the period from age 18 to the mid-twenties, when many young people are not yet fully independent. But observers note that this stage is found mostly in today’s Western cultures.

Adulthood

5-17 What physical changes occur during middle and late adulthood?

Muscular strength, reaction time, sensory abilities, and cardiac output begin to decline in the late twenties and continue to decline throughout middle adulthood (roughly age 40 to 65) and late adulthood (the years after 65). Women’s period of fertility ends with menopause around age 50; men have no similar age-related sharp drop in hormone levels or fertility. In late adulthood, the immune system weakens, increasing susceptibility to life-threatening illnesses. Chromosome tips (telomeres) wear down, reducing the chances of normal genetic replication. But for some, longevity-supporting genes, low stress, and good health habits enable better health in later life.

5-18 How does memory change with age?

As the years pass, recall begins to decline, especially for meaningless information, but recognition memory remains strong. Older adults rely more on time management and memory cues to remember time-based and habitual tasks. Developmental researchers study age-related changes such as in memory with cross-sectional studies (comparing people of different ages) and longitudinal studies (retesting the same people over a period of years). “Terminal decline” describes the cognitive decline in the final few years of life.

5-19 How do neurocognitive disorders and Alzheimer’s disease affect cognitive ability?

Neurocognitive disorders (NCDs) are acquired (not lifelong) disorders marked by cognitive deficits, which are often related to Alzheimer’s disease, brain injury or disease, or substance abuse. This damage to brain cells results in the erosion of mental abilities that is not typical of normal aging. Alzheimer’s disease is marked by neural plaques, often with an onset after age 80, entailing a progressive decline in memory and other cognitive abilities.

5-20 What themes and influences mark our social journey from early adulthood to death?

Adults do not progress through an orderly sequence of age-related social stages. Chance events can determine life choices. The social clock is a culture’s preferred timing for social events, such as marriage, parenthood, and retirement. Adulthood’s dominant themes are love and work, which Erikson called intimacy and generativity.

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5-21 How does our well-being change across the life span?

Self-confidence tends to strengthen across the life span. Surveys show that life satisfaction is unrelated to age. Positive emotions increase after midlife and negative ones decrease.

5-22 A loved one’s death triggers what range of reactions?

People do not grieve in predictable stages, as was once supposed. Strong expressions of emotion do not purge grief, and bereavement therapy is not significantly more effective than grieving without such aid. Erikson viewed the late-adulthood psychosocial task as developing a sense of integrity (versus despair).