I. Introduction: Your Life Story Developmental psychology is the study of how people change physically, mentally, and socially throughout the

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1 I. Introduction: Your Life Story Developmental psychology is the study of how people change physically, mentally, and socially throughout the lifespan. 1. At every age and stage of life, developmental psychologists investigate the influence of multiple factors on development, including biological, environmental, social, cultural, and behavioral factors. 2. Along with studying common patterns of growth and change, developmental psychologists look at the ways in which people differ in their development and life stories. 3. Developmental psychologists often conceptualize the lifespan in terms of basic stages of development, which are defined by age. 4. Some aspects of development, such as prenatal development and language development, are closely tied to critical periods. 5. The theme of the typical course of human development is gradually unfolding changes. 6. Another important theme is the interaction between heredity and environment, traditionally called the nature nurture issue. II. Genetic Contributions to Your Life Story A. Genetic Makeup 1. The zygote is the single cell formed at conception; it contains the unique set of genetic instructions inherited from your biological parents. 2. Chromosomes are long, threadlike structures composed of twisted parallel strands of deoxyribonucleic acid (DNA) and are found in the nucleus of the cell. 3. DNA is the chemical basis of heredity; the DNA code carried on each chromosome is arranged in thousands of segments called genes. 4. Each gene is a unit of DNA instructions for making a particular protein molecule. Proteins are used in virtually all of the body s functions. B. Your Unique Genotype 1. At conception, the genes carried on the 23 chromosomes contributed by your biological mother s ovum were paired with the genes carried on the 23 chromosomes contributed by your biological father s sperm, creating your unique genetic makeup or genotype.

2 2. The differences between the different types of body cells are due to which genes are expressed, or activated, at different times. 3. The Human Genome Project greatly advanced our knowledge of DNA and gene activity by producing a map of the human genome, the complete set of DNA in the human organism. 4. Genes can come in different versions, called alleles. a. Your genotype includes two copies of each gene one from each parent. These genes may be identical or different. The range of potential alleles for individual genes varies. b. It is the unique combination of alleles that makes each person s genotype unique. c. The best-known pattern of allele variation is the simple dominant recessive gene pair. Most characteristics, however, involve the interaction of multiple genes. C. From Genotype to Phenotype 1. While genotype refers to the underlying genetic makeup of a particular individual, phenotype refers to the characteristics that are actually displayed. 2. The analogy of a person s genotype to a blueprint is inaccurate. a. Genes themselves don t actually control physical development or behavior. A person s genotype can more accurately be described as a cookbook containing a collection of recipes (genes) for building proteins for every conceivable occasion. b. Genetic activity is far from fixed or inevitable. Rather, it is flexible, responding to the organism s internal state or external environment. 3. Different genotypes react differently to environmental factors. Thus, behavioral genetics researchers will often speak of genetic predispositions to develop in a particular way. 4. Genes can also mutate, or spontaneously change, and DNA can be damaged by environmental factors. Errors in the genetic code can disrupt the production of the correct proteins and lead to birth defects or genetic disorders.

3 III. Prenatal Development At conception, chromosomes from the biological mother and father combine to form a single cell the fertilized egg, or zygote. The prenatal stage has three distinct phases: the germinal period, the embryonic period, and the fetal period. A. The germinal period, also called the zygotic period, represents the first two weeks of prenatal development. The zygote undergoes rapid cell division before becoming implanted on the wall of the mother s uterus. By the end of the two-week germinal period, the single-celled zygote has developed into a cluster of cells called the embryo. B. The embryonic period begins with week 3 and extends through week 8. During this time of rapid growth and intensive cell differentiation, the organs and major systems of the body form. Genes on the sex chromosomes and hormonal influences trigger the initial development of the sex organs. 2. The embryo is protectively housed in the fluid-filled amniotic sac; the embryo s lifeline is the umbilical cord. a. Via the umbilical cord, the embryo receives nutrients, oxygen, and water and gets rid of carbon monoxide and other wastes. b. The umbilical cord attaches the embryo to the placenta, a diskshaped tissue on the mother s uterine wall. The placenta prevents the mother s blood from mingling with that of the developing embryo, acting as a filter to prevent some, but not all, harmful substances that might be present in the mother s blood from reaching the embryo. 3. Teratogens are harmful agents or substances that can cause abnormal development or birth defects. Known teratogens include: a. Exposure to radiation. b. Toxic industrial chemicals, such as mercury and PCBs. c. Diseases, such as rubella, syphilis, genital herpes, and AIDS. d. Drugs taken by the mother, such as alcohol, cocaine, and heroin. C. Beginning with the third month, the fetal period is the final and longest stage of prenatal development. 1. By the end of the third month, the fetus can move its arms, legs, mouth, and head.

4 2. During the fourth month, the mother experiences quickening she can feel the fetus moving. 3. By the fifth month, all the brain cells are present, and the fetus has distinct sleep wake cycles and periods of activity. 4. During the sixth month, the fetus s brain activity becomes similar to that of a newborn baby. 5. During the final two months, the fetus will double in weight. IV. Development During Infancy and Childhood A. The Newborn 1. Initially, the newborn s behavior is mostly limited to reflexes. a. Touching the newborn s cheek triggers the rooting reflex. b. Touching the newborn s lips evokes the sucking reflex. c. Because of the grasping reflex, the baby will grip your fingers so tightly that he or she can be lifted upright. 2. The newborn s senses vision, hearing, smell, and touch are keenly attuned to people, helping the infant quickly learn to differentiate between the mother and other humans. a. Within just hours of birth, newborns display a preference for their mother s voice and face over that of a stranger. b. Vision is the least developed sense at birth. Optimal viewing distance for the newborn is about 6 to 12 inches, the perfect distance for a nursing baby to easily focus on his mother s face and make eye contact. B. Physical Development 1. At birth, the newborn s brain is 25 percent of her adult weight; the newborn s birth weight, by contrast, is 5 percent of her eventual adult weight. 2. The basic sequence of motor skill development during infancy is universal, but the average ages can be a little deceptive. Each infant has his or her own genetically programmed timetable of physical maturation and developmental readiness to master different motor skills. C. Social and Personality Development 1. Temperamental qualities: Babies are different! a. Inborn predispositions to consistently behave and react in a certain way define temperament.

5 b. In the 1950s, Thomas and Chess rated young infants on a variety of characteristics, such as activity level, mood, regularity in sleeping and eating, and attention span. (1) About a third of the infants were characterized as average babies because they did not fit neatly into one of three broad temperamental patterns. (2) Easy babies readily adapt to new experiences, generally display positive moods and emotions, and have regular sleeping and eating patterns. (3) Difficult babies tend to be intensely emotional, are irritable and fussy, and tend to have irregular sleeping and eating patterns. (4) Slow-to-warm-up babies have a low activity level, withdraw from new situations and people, and adapt to new experiences very gradually. c. Jerome Kagan has classified temperament in terms of reactivity. (1) High-reactive infants react intensely to new experiences, strangers, and novel objects. They tend to be tense, fearful, and inhibited. (2) Low-reactive infants tend to be calmer, uninhibited, and bolder. They tend to be sociable and are more likely to show interest than fear when exposed to new people, experiences, and objects. d. Virtually all temperament researchers agree that temperament has a genetic and biological basis but that environmental experiences can modify a child s basic temperament. e. Cultural beliefs can also affect infant temperament. 2. Attachment: Forming emotional bonds a. Attachment is the emotional bond that forms between infant and caregivers, especially his parents. b. According to the attachment theory developed by John Bowlby and Mary D. Salter Ainsworth, an infant s ability to thrive physically and psychologically depends in part on the quality of attachment. c. Infants can form multiple attachments. d. Depending on the parents, infants can form secure or insecure attachments.

6 (1) Secure attachment occurs when parents are consistently warm, responsive, and sensitive to their infant s needs. (2) Cross-cultural studies have confirmed that sensitivity to the infant s needs is associated with secure attachment in diverse cultures. (3) Insecure attachment may develop when an infant s parents are neglectful, inconsistent, or insensitive to the infant s moods or behaviors. 3. Culture and Human Behavior: Where Does the Baby Sleep? a. In most U.S. families, infants sleep in their own beds. In many other societies, however, infants sleep in the same beds or room as their mothers. b. For example, infants in Mayan families in Guatemala sleep with their mothers until they are 2 or 3. c. The different sleeping customs of the American and Mayan families reflect different cultural values, with American parents encouraging the infant to be independent and the Mayan parents encouraging the infant s feelings of interdependence with other family members. 4. The most commonly used procedure to measure attachment, called the Strange Situation, was developed by Ainsworth. It is typically used with infants between 1 and 2 years old. a. In the Strange Situation, the baby and mother are placed in an unfamiliar room for a few minutes with a variety of toys, then a stranger enters the room. b. The mother stays with the child for a few moments, then departs, leaving the child with the stranger. After a few minutes, the mother returns, spends a few minutes in the room, leaves, and returns again. (1) The securely attached infant will use the mother as a secure base from which to explore the new environment, periodically returning to her side. He will show distress when the mother leaves, will greet her warmly when she returns, and is easily soothed.

7 (2) Insecurely attached infants are less likely to explore the environment, appear either very anxious or completely indifferent, and tend to ignore or avoid their mothers when they are present. Some become extremely distressed when the mother leaves the room and, when reunited, are hard to soothe. (3) The quality of attachment during infancy is associated with a variety of long-term effects during early childhood, middle childhood, and adolescence. 5. Critical Thinking: The Effects of Child Care on Attachment and Development. a. High-quality day care can potentially benefit children, even when it begins in early infancy. b. Low-quality day care can potentially contribute to social and academic problems in later childhood. D. Language Development 1. According to linguist Noam Chomsky, children are born with a biological predisposition to learn language; that is, they possess what he calls a universal grammar a basic understanding of the common principles of language organization. a. At birth, infants can distinguish among the speech sounds of all the world s languages. b. By 10 months, they distinguish only the speech sounds that are present in the language to which they have been exposed. 2. Encouraging language development: Motherese a. People in every culture use a style of speech called motherese, or infant-directed speech, with babies. b. Motherese is characterized by distinct pronunciation, a simplified vocabulary, short sentences, a high pitch, and exaggerated intonation and expression. 3. The cooing and babbling stage of language development In virtually every culture, infants follow the same sequence of language development, and at roughly similar ages. a. At about 3 months of age, the infant begins to coo.

8 b. At about 5 months of age, the infant begins to babble. Infants all over the world use the same sounds when they babble. c. At around 9 months of age, babies begin to babble more in the sounds specific to their language. Babbling seems to be a biologically programmed stage of language development. 4. The one-word stage of language development a. Long before babies become accomplished talkers, they understand much of what is said to them. Thus, they have a comprehension vocabulary (the words they understand) that is much larger than their production vocabulary (the words they can say). b. Around their first birthday, infants produce their first real words usually referring to concrete objects or people that are important to them. c. During the one-word stage, babies use a single word and vocal intonation to stand for an entire sentence. 5. The two-word stage of language development a. Around their second birthday, infants begin putting words together to construct simple sentences. b. These utterances include only the most essential words, but basically follow a grammatically correct sequence. c. Children move beyond the two-word stage at around 21/2 years of age. Language production and comprehension increase dramatically thereafter children may have a production vocabulary of over 10,000 words by school age. V. Cognitive Development 1. The most influential theory of cognitive development is that of Swiss psychologist Jean Piaget, who believed that children actively try to make sense out of their environment rather than passively soaking up information about the world. a. According to Piaget, children progress through four distinct cognitive stages: the sensorimotor stage, the preoperational stage, the concrete operational stage, and the formal operational stage.

9 b. As a child advances to a new stage, his thinking is qualitatively different from that in the previous stage; each new stage represents a fundamental shift in how the child thinks and understands the world. c. As children assimilate new information and experiences, they eventually change their way of thinking to accommodate new knowledge. d. According to Piaget, the sequence of stages is universal, but heredity and environment can influence the rate at which children progress through the stages. 2. The sensorimotor stage a. During the sensorimotor stage, infants acquire knowledge about the world through actions that allow them to directly experience and manipulate objects. b. Infants gradually acquire object permanence (the understanding that an object continues to exist even if it can t be seen) as they gain experience with objects, as their memory abilities improve, and as they develop mental representations of the world, which Piaget called schemas. 3. The preoperational stage (age 2 to age 7) In Piaget s theory, the word operations refers to logical mental activities; thus, the preoperational stage is a prelogical stage. The thinking of preoperational children is characterized by a. symbolic thought, which refers to the ability to use words, images, and symbols to represent the world. b. egocentrism, which is the inability to take another person s perspective or point of view. c. irreversibility, which means that the child cannot mentally reverse a sequence of events or logical operations back to the starting point. d. centration, which refers to the tendency to focus, or center, on only one aspect of a situation, usually a perceptual aspect, and ignore other relevant aspects of the situation. e. the inability to understand conservation, the understanding that two equal quantities remain equal even if the appearance of one is changed, as long as nothing is added or subtracted.

10 4. The concrete operational stage (age 7 to age 11) is characterized by the ability to think logically about concrete objects and situations. 5. The formal operational stage (adolescence into adulthood) is characterized by the ability to think logically about abstract principles and hypothetical situations. 6. Criticisms of Piaget s theory a. Generally, scientific research has supported Piaget s most fundamental idea: that infants, young children, and older children use distinctly different cognitive abilities to construct their understanding of the world. b. Other aspects of Piaget s theory have been criticized. (1) Piaget underestimated the cognitive abilities of infants and young children. (a) Renée Baillargeon used visual tasks, rather than manual tasks, and found that young children achieve object permanence at an earlier age than Piaget proposed. (b) Baillargeon and her colleagues have also shown that infants develop event-specific expectations, rather than general principles. (2) Piaget underestimated the impact of the social and cultural environment on cognitive development. (a) Offering an alternative viewpoint, Russian psychologist Lev Vygotsky believed that cognitive development is strongly influenced by social and cultural factors, such as the support and guidance that children receive from parents, other adults, and older children. (b) The zone of proximal development refers to the gap between what children can accomplish on their own and what they can accomplish with the help of more competent others. (c) Cross-cultural studies have shown that cognitive development is strongly influenced by the skills that are valued and encouraged in a particular environment.

11 (3) Piaget overestimated the degree to which people achieve formal operational thought processes. (a) Researchers have found that many adults display abstract-hypothetical thinking only in limited areas of knowledge and that some adults never display formal operational thought processes. (b) Some developmental psychologists emphasize the information-processing model of cognitive development, which focuses on the development of fundamental mental processes, such as attention, memory, and problem solving. They view cognitive development as a process of continuous change over the lifespan that is influenced by life experiences. VI. Adolescence Adolescence is the transitional stage between late childhood and the beginning of adulthood. A. Physical and Sexual Development 1. Puberty is the stage of adolescence in which an individual reaches sexual maturity and becomes physiologically capable of sexual reproduction. Although there is great individual variation in timing, puberty tends to follow a predictable sequence for each sex. 2. Primary and secondary sex characteristics a. Internally, puberty involves the development of the primary sex characteristics, which are the sexual organs that are directly involved in reproduction, such as the uterus and testes. b. Externally, development of the secondary sex characteristics, which are not directly involved in reproduction, signal increasing sexual maturity. These include changes in height, weight, and body shape; appearance of body hair; voice changes; and, in girls, breast development. c. The period of marked acceleration in weight and height gains, called the adolescent growth spurt, occurs about two years earlier in females than in males.

12 d. A female s first menstrual period, termed menarche, typically occurs around age 12 or Factors affecting the timing of puberty a. Both genetics and environmental factors play a role in the timing of puberty. (1) Girls often experience menarche at about the same age as their mothers did. (2) Generally, well-nourished and healthy children begin puberty earlier than do children who have experienced serious health problems or inadequate nutrition. (3) In general, heavy children begin puberty earlier than do lean children, and girls involved in physically demanding athletic activity can experience delays in menarche. (4) The absence of the biological father in the home environment is linked to accelerated physical development. (5) Negative and stressful family environments are associated with an earlier onset of puberty, while positive family environments are associated with later physical development. 4. Focus on Neuroscience: The Adolescent Brain: A Work in Progress a. MRI scans have revealed two distinct spurts of brain development one during prenatal development and one during late childhood just prior to puberty. b. As the brain matures, neuronal connections are pruned and gray matter diminishes in a back-to-front wave. c. The last brain area to experience pruning and maturity is the prefrontal cortex, which plays a critical role in many advanced cognitive functions, such as reasoning, planning ahead, organizing, solving problems, and decision making. d. The prefrontal cortex does not reach full maturity until the mid twenties, which may provide a partial explanation for an adolescent s occasional impulsive or immature behavior. 5. Early versus late maturation

13 a. Most adolescents are on time maturational changes are occurring at roughly the same time for them as for others in their peer group. b. For girls, early maturation is associated with a greater risk for a variety of negative health and psychological outcomes, such as poor body image, higher rates of teenage pregnancy, and unhealthy weight gain later in life. c. Early-maturing boys tend to be popular with their peers, but they are also more susceptible to behaviors that put their health at risk. They are also more prone to symptoms of depression, problems at school, and drug and alcohol use. B. Social Development 1. As a general rule, when parent child relationships have been good before adolescence, they continue to be relatively smooth during adolescence. a. Relationships with friends and peers become increasingly important. b. Peer relationships tend to reinforce the traits and goals that parents fostered during childhood. 2. Culture and Human Behavior: Conflict Between Adolescents and Their Parents a. Many developmental psychologists view the increased conflict in early and middle adolescence as healthy, a necessary stage in the adolescent s development of increased independence and autonomy. b. Cross-cultural research suggests that parent adolescent conflict is a common dimension of family life in both individualistic and collectivistic cultures. c. Even within cultural and ethnic groups that traditionally emphasize parental authority, adolescents are motivated to assert their independence and developing autonomy. d. Adolescents tend to form friendships with peers whose social class, race, and beliefs are similar to their own. e. Although peer influence can be negative, it can also be positive. f. Romantic attachments and sexual relationships become increasingly important throughout the adolescent years.

14 3. Identity Formation: Erikson s Theory of Psychosocial Development a. Identity is a person s definition or description of himself or herself, including the values, beliefs, and ideals that guide the individual s behavior. b. Psychoanalyst Erik Erikson proposed a theory of psychosocial development consisting of eight stages of life, each associated with a particular psychosocial conflict that can be resolved in either a positive or negative direction. c. According to Erikson, the key psychosocial conflict facing adolescents is identity versus role confusion. (1) The adolescent s path to successful identity achievement begins with role confusion. This is followed by a moratorium period. Gradually, the adolescent arrives at an integrated identity. (2) Research has generally supported Erikson s description of the process of identity formation. VII. Adult Development A. Physical Changes 1. Physical strength typically peaks in early adulthood, the twenties and thirties; by middle adulthood, roughly from the forties to mid sixties, physical strength and endurance gradually decline; and during late adulthood, from the mid-sixties on, physical stamina and reaction time tend to decline further and faster. 2. Your unique genetic blueprint greatly influences the unfolding of certain physical changes during adulthood. For example, menopause, the cessation of menstruation that signals the end of reproductive capacity in women, may occur anywhere from the late thirties to the early fifties. 3. Staying mentally and physically active and eating a proper diet can both slow and minimize the degree of physical decline associated with aging. B. Social Development 1. In his theory of psychosocial development, Erik Erikson described two fundamental themes that dominate adulthood: love and work.

15 a. According to Erikson, the primary psychosocial task of early adulthood is to form a committed, mutually enhancing, intimate relationship with another person. b. During middle adulthood, the primary psychosocial task becomes one of generativity, to contribute to future generations through your children, your career, and other meaningful activities. 2. Friends and lovers in adulthood a. Female friends tend to confide in one another about their feelings, problems, and interpersonal relationships. b. Male friends typically minimize discussions about relationships or personal feelings or problems; instead, male friends tend to do things together that they find mutually interesting, such as activities related to sports or hobbies. c. Today, many young adults postpone marriage so they can finish their education and establish a career. In 2003, the median age for first marriage was 27 for men and 25 for women. d. As a general rule, we tend to be attracted to and marry people who are similar to us on a variety of dimensions, including physical attractiveness, social and educational status, ethnic background, attitudes, values, and beliefs. 3. The Transition to Parenthood: Kids R Us? a. Marital satisfaction tends to decline after the birth of the first child and rise again after children leave home. b. Becoming a parent at an older age and waiting longer after marriage to start a family help ease the adjustment to parenthood. 4. Variations in the Paths of Adult Social Development a. At the end of the twentieth century, well over 3 million unmarried couples were living together. b. More than 30 percent of children are being raised by a single parent. c. More than half of all first marriages end in divorce, so remarrying and starting a second family later in life is not unusual. d. There are also gay and lesbian couples in committed, long-term, monogamous relationships.

16 e. In the final analysis, any relationship that promotes the overall sense of happiness and well-being of the people involved is a successful one. 5. Careers in Adulthood a. Researchers have found that close to a third of people in their late twenties and early thirties do not just change jobs within a particular field they completely switch occupational fields. b. Dual-career families have become increasingly common. c. Although many fathers are actively involved in child rearing, women still tend to have primary responsibility for child care. d. Multiple roles seem to provide both men and women with a greater potential for increased feelings of selfesteem, happiness, and competence. The critical factor is not the number of roles that people take on but the quality of their experiences on the job, in the marriage, and as a parent. VIII. Late Adulthood and Aging A. Health in Late Adulthood 1. The average life expectancy for men in the United States is about 75 years; for women, it is about 80 years. 2. The majority of older adults live healthy, active, and selfsufficient lives. Only 4.5 percent of those age 65 and over live in nursing homes; among those age 85 and over, it is fewer than 20 percent. 3. The number of older adults in the United States has been gradually increasing over the past several decades. Today, one in eight Americans is 65 or older. B. Cognitive Changes 1. Psychologist K. Warner Schaie and his colleagues have found that general intellectual abilities gradually increase until one s early forties, then become relatively stable until about age 60, when a small but steadily increasing percentage of older adults experience slight declines on tests of general intellectual abilities. 2. Schaie found that those who were better educated and engaged in physical and mental activities throughout older adulthood showed the smallest declines in mental abilities.

17 C. Social Development 1. According to the activity theory of aging, life satisfaction in late adulthood is highest when people maintain their previous level of activity. 2. For many older adults, caregiving responsibilities (for grandchildren or other older adults) can persist well into late adulthood. 3. The social support provided by a confidant yields important psychological benefits, such as higher morale, better mental health, and better psychological well-being. 4. Along with satisfying social relationships, the prescription for psychological well-being in old age includes achieving what Erik Erikson called ego integrity the feeling that one s life has been meaningful. In contrast, those who are filled with regrets or bitterness about past mistakes, missed opportunities, or bad decisions experience despair. 5. Often the theme of ego integrity versus despair emerges as older adults engage in a life review. IX. The Final Chapter: Dying and Death Attitudes toward dying and death are as diverse in late adulthood as they are throughout the lifespan. In general, anxiety about death tends to peak in middle adulthood, then to decrease in late adulthood. 1. Elisabeth Kübler-Ross proposed that the dying go through five stages. They: a. deny that death is imminent; b. feel and express anger that they are dying; c. bargain they try to make a deal with doctors, relatives, or God; d. become depressed; and finally e. accept their fate. 2. Further research indicates that dying individuals do not necessarily progress through a predictable sequence of stages. Dying is as individual a process as is living. People cope with the prospect of dying much as they have coped with other stresses in their lives. X. Application: Raising Psychologically Healthy Children A. Basic Parenting Styles 1. Parents with an authoritarian parenting style are demanding and unresponsive toward their children s needs and wishes.

18 2. Parents with a permissive parenting style may be permissive indulgent (responsive, warm, and accepting, but impose few rules and rarely punish) or permissive-indifferent (unresponsive and uncontrolling). 3. Parents with an authoritative parenting style set clear standards for their children s behavior but are warm, responsive, and involved with their children. B. Effects on Children 1. Children of authoritarian parents are likely to be moody, unhappy, fearful, withdrawn, unspontaneous, and irritable; this style promotes resentment and rebellion. 2. Children of permissive parents tend to be immature, impulsive, and aggressive, and they may never learn selfcontrol. 3. Children of authoritative parents tend to be cheerful, socially competent, energetic, and friendly. They show high levels of self-esteem, self-reliance, and self-control. C. How to Be an Authoritative Parent: Some Practical Suggestions 1. Let your children know that you love them. 2. Listen to your children. 3. Use induction to teach as you discipline. 4. Work with your child s temperamental qualities. 5. Understand your child s age-related cognitive abilities and limitations. 6. Don t expect perfection, and learn to go with the flow.