Lifespan Development

Chapter Nine

Lecture Slides

By Glenn MeyerTrinity University

IntroductionDevelopmental psychology is the study of how people change over the lifespan. • Focuses on psychological changes

across the entire lifespan• Every area of psychology can be looked

at from this perspective• Biological development• Social development• Cognitive/perceptual development

Critical Issues• Can some development be described in

terms of stages?• Are there critical periods during which the

child is maximally sensitive to environmental issues?

• What part of development can be described as gradually unfolding changes?

• We need to investigate the interaction between heredity and environment, known as the nature–nurture issue

Genetic ContributionsImportant Terms

Zygote — single cell formed at conception from union of egg cell and sperm cell

Chromosome — a long, thread-like structure composed of twisted parallel strands of DNA; found in cell nucleus

Deoxyribonucleic acid (DNA) — double-stranded molecule that encodes genetic instructions; chemical basis of heredity

Gene — a segment of DNA on a chromosome that encodes instructions for making a particular protein molecule; basic unit of heredity

Genotype — genetic makeup of an individual organism

Alleles — different forms of a particular gene

Sex chromosomes — chromosomes, designated as X or Y, that determine biological sex; 23rd pair of chromosomes in humans

Phenotype — observable traits or characteristics of an organism as determined by interaction of genetics and environmental factors

ZygoteClick here

ChromosomeClick here

Deoxyribonucleic acid (DNA)Click here

GeneClick here

GenotypeClick here

AllelesClick here

Sex chromosomesClick here

PhenotypeClick here

Chromosomes, Genes and DNA

23 pairs of human chromosomes

X and Y chromosomes

Your Unique Genotype• Mother’s egg cell and father’s sperm cell each

contributed 23 chromosomes • Set of 23 chromosome pairs represents your unique

genotype or genetic makeup• Human genome contains only about 20,000 to 25,000

protein-coding genes• Dominant genes will always be expressed if present• Recessive genes will not be expressed unless they are

in a pair• Most characteristics involve the interaction of multiple

genesFrom Genotype to Phenotype• Different genotypes react differently to environmental

factors• Psychologists and scientists believe people have

genetic predispositions to develop in a particular way• Most of the genes in each person are dormant • Experience affects which genes are turned on (and off)• Environment participates in sculpting the expression of

the genome

Examples: brown eyes, five fingers

Examples: blue eyes, extra fingers

Epigenetics

• Gene expression can be triggered by the activity of other genes, internal chemical changes, or by external environmental factor

• Epigenetic “settings” determine whether a cell will become a skin cell, a nerve cell, or a heart muscle cell• Suicide victims who had been abused as

children had distinct epigenetic marks in brain tissue that were not found in suicide victims who had not been abused as children or in accident victims.

Study of the cellular mechanisms that control gene

expression and of the ways that gene expression affects

health and behavior

Prenatal DevelopmentGerminal and Embryonic Periods

Conception—when a

sperm penetrates the ovum

Zygote—a fertilized

egg

Germinal period—first two

weeks after conception

Embryonic period—

weeks three through eight

after conception

Fetal period—two

months after conception until birth

Embryonic PeriodRisk of teratogens

• Exposure to radiation• Toxic chemicals and metals, such as

mercury, PCBs, and lead• Viruses and bacteria, such as German

measles (rubella), syphilis, genital herpes, and human immunodeficiency virus (HIV)

• Prescription painkillers and other prescription and nonprescription drugs

• Addictive drugs, including heroin, sedatives, cocaine, amphetamines, and methamphetamine

• Maternal smoking and exposure to second-hand smoke

• Alcohol — Fetal alcohol syndrome: abnormal facial features, poor coordination, learning disabilities, behavior problems, and mental retardation

• Mother’s psychological state, unhealthy behaviors

Teratogens—any agent that

causes a birth defect

Prenatal Brain Development

During peak periods of brain development, new neurons are being generated at the rate of 250,000 per minute.

• Brain begins as a fluid-filled neural tube about three weeks after conception

• The neural tube is lined with stem cells

• Neural stem cells divide and multiply, producing neurons and glial cells

• Top of tube thickens into three bulges that form the hindbrain, midbrain, and forebrain • Hindbrain structures are first to

develop • Followed by midbrain

structures• Forebrain structures develop

last, eventually surrounding and enveloping the hindbrain and midbrain structures

Fetal Period• Third and longest period of prenatal development, extending

from the ninth week until birth• Main task: body systems grow and reach maturity in

preparation for life outside mother’s body• Fetal brain is forming as many as 2 million synaptic

connections per second • Connections that are used are strengthened, while

connections that remain unused are eventually pruned or eliminated

• Fetus has distinct sleep–wake cycles and periods of activity • During sixth month, fetus’s brain activity becomes similar to

newborn baby’s• At birth, newborn’s brain is one-fourth the size of adult brain,

weighing less than 1 pound • After birth, neurons grow in size and continue to develop

new dendrites and interconnections with other neurons • Myelin forms on axons in key areas of the brain, such as

those involved in motor control

Development During Infancy and Childhood

Newborn Reflexes• Rooting—turning the head and opening

the mouth in the direction of a touch on the cheek

• Sucking—sucking rhythmically in response to oral stimulation

• Babinski—fanning and curling toes when foot is stroked

• Grasping—the baby will grip your fingers so tightly that he can be lifted upright

Newborn Senses • Newborn infant is extremely nearsighted

• Image of a human face holds the newborn’s gaze longer than do other images

• Optimal viewing distance for the newborn is about 6 to 12 inches

• Newborns only 10 minutes old will turn their heads to continue gazing at the image of a human face as it passes in front of them, but they will not visually follow other images

• Within just hours of birth, a newborn displays a preference for her mother’s voice and face over a stranger’s

Physical Development Patterns• During infancy, the brain will grow to about 75 percent of its adult

weight• Cephalocaudal pattern — physical and motor skill development

tends to follow a “top to bottom” sequence• Proximodistal trend — develop motor control from the center of

bodies outwards• Basic sequence of motor skill development is universal, but the

average ages can be a little deceptive

Reactivity (Kagan)Click here

Social and Personality DevelopmentTemperamental Qualities: Babies Are Different!Classic distinctions (Thomas and

Chase)Click here

• Easy—adaptable, positive mood, regular habits

• Slow to warm up—low activity, somewhat slow to adapt, generally withdraw from new situations

• Difficult—intense emotions, irritable, cry frequently

• Average—unable to classify (1/3 of all children)

• High-reactive infants react intensely to new experiences, strangers, and novel objects

• Low-reactive infants tend to be calmer, uninhibited, and bolder

Influences• Individual differences in temperament have a genetic and

biological basis• Environmental experiences can modify a child’s basic

temperament• Infant temperament can also be affected by cultural beliefs

Attachment: Forming Emotional Bonds

The emotional bond that forms between the infant and caregivers, especially parents, during the first year of life is called attachment.

Ainsworth’s Strange Situation

Mother-child dyads were observed in a playroom under four conditions: • Initial mother-child interaction• Mother leaves infant alone in

playroom• Friendly stranger enters

playroom• Mother returns and greets

child

Forms of Attachment

Securely attached infants explore the room when

mother is present, become upset and explores less

when mother is not present, and show

pleasure when mother returns

Insecurely attached babies are less likely to

explore the environment, even when their mother is

present

Avoidant attachment

a form of insecure attachment in which the

child avoids his mother and acts coldly to her

Anxious resistant attachment

a form of insecure attachment in which the child remains close to mother and remains

distressed despite her attempts to comfort

Baby Sleeping Arrangements• United States: Babies usually sleep in their own beds• Mayan families and other cultures allow baby to sleep

with mother until 2 or 3 years old• Differences because of pragmatic reasons – staying

warm?• Reflects different cultural values of independence and

interdependence• Should the baby be independent and self-reliant?

Language DevelopmentUniversal Characteristics

• By the time a child reaches 3 years of age, she will have learned approximately 3,000 words and many complex rules of language

• Noam Chomsky (1965): every child is born with a biological predisposition to learn language—any language

• Infants can distinguish among the speech sounds of all the world’s languages

• Infants lose this ability by 10–12 months of age

Encouraging Language DevelopmentMothers, Parents, or Infant-Directed Speech

Very distinct pronunciation

Simplified vocabulary

Short sentences

High pitch and exaggerated intonation and expression

Content is restricted to topics that are familiar to the child

Adult use of infant-directed speech seems to be instinctive

Infants seem to prefer infant-directed

Found with deaf mothers and signing

• Comprehension vocabulary (the words she understands) is much larger than her production vocabulary

• Babies produce their first real words around their first birthday

• Words usually refer to concrete objects or people that are important to the child

• Single words and vocal intonation stand for an entire sentence

• Cooing • 3 months of age• Repeating vowel sounds, such as ahhhhh

or ooooo• Babbling

• Consonant/vowel sounds at 5 months of age

• ba-ba-ba-ba, de-de-de-de, or ma-ma-ma-ma

• Infants all over the world use the same sounds when they babble, including sounds that do not occur in the language of their parents

• At around 9 months of age, babies begin to babble more in the sounds specific to their language

• Babbling is biologically programmed

One-Word Stage of Language Development

Click here

Cooing and Babbling Stage of Language Development

Click here

• Occurs around child’s second birthday• Use two words to construct a simple “sentence”

Examples: “Mama go.” “Where kitty?” “No potty!” • Primarily content words—nouns, verbs, and sometimes adjectives or

adverbs• Articles (a, an, the) and prepositions (such as in, under, on) are omitted.• At 2½ years of age, most children can increase length and grammatical

complexity of sentences • At age 3, most children have a production vocabulary of more than 3,000

words• Acquiring about a dozen new words per day, a child may have a production

vocabulary of more than 10,000 words by school age

Two-Word Stage of Language Development

Click here

Cognitive Development

• Jean Piaget — most influential theory of cognitive development

• Believed that children actively try to make sense of environment rather than passively soaking up information

• Children progress through four distinct cognitive stages: sensorimotor, preoperational, concrete operational, formal operational• As a child advances to a new stage, thinking is

qualitatively different• Develops a new understanding of world in each

progressive stage, building on understandings acquired in the previous stage

• Child assimilates new information and experiences, changes his way of thinking to accommodate new knowledge

• Information is gained through the senses and motor actions

• In this stage child perceives and manipulates but does not reason

• Symbols become internalized through language development

• Object permanence: the understanding that objects exist independent of one’s actions or perceptions of them• Before 6 months of age infants

act as if objects removed from sight cease to exist –Can be surprised by disappearance/reappearance of a face (peek-a-boo)

Sensorimotor StageBirth - 2 years

• Emergence of symbolic thought: ability to use words, images, and symbols to represent the world

• Centration: tendency to focus, or center, on only one aspect of a situation, usually a perceptual aspect

• Egocentrism: egocentric children lack the ability to consider events from another person’s point of view

• Lack concept of conservation• Two equal physical quantities remain

equal even if the appearance of one is changed, as long as nothing is added or subtracted

• No understanding of irreversibility• Animism• Artificialism

Preoperational Stage2 - 7 years

• Understanding of mental operations leading to increasingly logical thought

• Classification and categorization• Less egocentric• Inability to reason abstractly or hypothetically• Understand concept of conservation

Example: When presented with two rows of pennies, each row equally spaced, concrete operational children understand that the number of pennies in each row remains the same even when the spacing between the pennies in one row is increased.

Concrete Operational Stage7-12 years

Formal Operational Stage12 years – Adulthood

• Solves complex and hypothetical problems

• Able to think in abstract terms

Criticisms of Piaget’s Theory

Baillargeon and her colleagues have shown that infants as young as 2½ months of age display object permanence.

Criticism 1Piaget underestimated the cognitive abilities of infants and young children

Click here

Lev Vygotsky • Believed that cognitive

development is strongly influenced by social and cultural factors

• Children are able to attain higher levels of cognitive development through the support and instruction that they receive from other people

• Zone of proximal development—what a child can do by interacting with another person, but can’t do alone

• Critical thinking based on dialogue with others who challenge ideas

• Findings suggest that Piaget’s stages are not as universal and culture-free as some researchers had once believed

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 at all.Information-Processing Perspective• Rather than distinct stages of cognitive

development (Piaget), some developmental psychologists emphasize this model

• Views cognitive development as a process that is continuous over the lifespan; studies development of basic mental processes (attention, memory, problem solving)

Criticism 2Piaget underestimated the impact of social and cultural environment on cognitive development

Click here

Criticism 3Piaget overestimated degree to which people achieve formal operational thought processes

Click here

Adolescence• Transitional stage between late

childhood and early adulthood, during which sexual maturity is reached

• Adolescence is the stage that marks the transition from childhood to adulthood

• Puberty—stage at which an individual reaches sexual maturity and is physically capable of sexual reproduction

• Primary sex characteristics—sex organs directly involved in reproduction

• Secondary sex characteristics—develop during puberty, not directly involved in reproduction, but distinguish male from female

• Adolescent growth spurt—period of accelerated growth during puberty

• Menarche—female’s first menstrual period, typically occurs around age 12 or 13

• Testicles typically begin enlarging around age 11 or 12; girls are typically about two years ahead of boys in terms of physical and sexual maturation

Physical and Sexual Development

• Little evidence of “raging hormones” causing emotional problems

• Neuronal pruning surges occur• Prefrontal cortex is the last area to experience pruning,

which is responsible for executive cognitive functions, such as reasoning, planning, and organizing

• Second wave of gray matter overproduction just prior to puberty, followed by a second round of neuronal pruning during the teenage years

• The prefrontal cortex reaches full maturity by mid-20s. An adolescent’s occasional impulsive, risky or immature behavior is due to a brain that has not reached full adult maturity.

The Adolescent Brain

Factors that Affect the Timing of Puberty

Click here

Genetics—girls experience

menarche around same age as their

mother did, closer for identical twins than

nontwin siblings

Environment—nutrition and health

Body size and physical activity• Heavier children begin

puberty earlier• Physically demanding

exercise delays menarche

Absence of the father in the home environment • Menarche comes earlier

for girls in these homes• Boys in these homes

have accelerated physical development

Quality of family

relationship

Effects of Early Versus Late Maturation

Girls who develop early and boys who develop late are most likely to

have problems

Boys• Early maturation can be

advantageous for boys (popularity, athletics)

• Risks include depression, drug use

Girls: • Early-maturing girls are more likely

than late-maturing girls to have negative feelings about body image and pubertal changes

• Embarrassed by unwanted attention from older males

• Higher rates of sexual risk-taking, substance use, and delinquent behavior

• At greater risk for unhealthy weight gain later in life

Social Development

• Parent-child relationships overall positive, but conflict does increase during this time; this is seen as healthy as autonomy increases

• Friends and peers become more of an influence• Peer relationships tend to reinforce the traits and goals

that parents fostered during childhood• Romantic relationships influence psychological and

social development in both positive and negative ways• By age of 12, about 25 percent of adolescents report a

“special romantic relationship”• By age 15: 50 percent; by age 18: 70 percent • Social and cultural factors influence when, why, and how

adolescents engage in romantic and sexual behaviors

IdentityA person’s sense of self,

including his or her memories, experiences, and the values and beliefs that guide his or

her behavior.

Identity Formation Erikson’s Theory of Psychosocial DevelopmentErikson: • Divided life span into

eight psychosocial stages, each associated with a different drive and a problem or crisis to resolve

• Outcome of each stage varies along a continuum from positive to negative

• Psychological research has generally supported Erikson’s description of the process of identity formation

Kohlberg• Most influential theory of moral development was

proposed by Kohlberg, who concluded that there are distinct stages of moral development.

• Kohlberg’s original belief that the development of abstract thinking in adolescence naturally and invariably leads people to the formation of idealistic moral principles has not been supported

• Moral reasoning for most people seems to be captured by Kohlberg’s first four stages

• By adulthood, the predominant form of moral reasoning is conventional moral reasoning, reflecting the importance of social roles and rules

Development of Moral ReasoningMoral reasoning

how an individual thinks about moral decisions

• Most important criticism of Kohlberg’s theory is that moral reasoning doesn’t always predict moral behavior

• Moral decisions in the real world are often affected by no rational processes, such as emotional responses, custom, or tradition

• Based on research on males

• Based on Western perspective of individual rights and justice

• Doesn’t take into account collectivist values, religious purity, or loyalty to family

Critiques of Kohlberg’s Theory

Gender, Culture, and Moral Reasoning

• Kohlberg’s theory based on male participants• Kohlberg’s model based on ethic of individual rights and

justice, more common perspective for men• Gilligan (1982) developed a model of women’s moral

development based on an ethic of care and responsibility• Gilligan found women tend to stress importance of

maintaining interpersonal relationships and responding to needs of others

• Research shows that Kohlberg may be incorrect, but so was Gilligan

• Evidence suggests that both men and women used a mix of care and justice perspectives

• Physical strength typically peaks in early adulthood: the 20s and 30s

• By middle adulthood, roughly from the 40s to the mid-60s, physical strength and endurance gradually decline

• Physical and mental reaction times also begin to slow during middle adulthood

• During late adulthood, from the mid-60s on, physical stamina and reaction time tend to decline further and faster

• Loss of lean muscle, increased body fat, weakened bones, and cognitive decay

Adult Development Development during adulthood is marked by physical changes and the adoption of

new social roles.

Physical changes: With each decade after age 20, the efficiency of various body organs declines.

Andropause in Men

Middle-aged men do not experience an abrupt end to their

reproductive capability

Experience a gradual decline in

testosterone levels

Erectile dysfunction, reduced sexual motivation and

function

Menopause in Women

Signals the end of reproductive capacity

Occurs any time from the late 30s to the

early 50s

Friends and Lovers in Adulthood• Adults typically have fewer friends than adolescents do• Female friends tend to confide in one another• Male friends tend to do things of mutual interest• Young adults are marrying at a later average age• “Traditional” family may no longer be the norm

Social Development Middle adulthoodThe primary psychosocial task becomes one of generativity—

to contribute to future generations through your children, your career, and

other meaningful activities.

The Median Age at First Marriage

Late Adulthood and Aging

• Life expectancy for men in the United States is 75 years; for women it’s 80 years

• Old age as a time of poor health, inactivity, and decline is a myth

• Decline in mental abilities is often because of lack of practice or experience

• Activity theory of aging—life satisfaction is highest when people maintain level of activity they had in earlier years

• Mental abilities remain relatively stable until about the age of 60

• Most older adults maintain their previous levels of ability

• 70s, 80s, and 90s show slight but significant declines in memory, perceptual speed, and fluency

• Measures of knowledge, such as vocabulary, remained stable up to age 90

• Neurons appear to become less efficient at communicating with one another

• Older brains compensate for decline in processing speed by outsourcing to other parts of the brain

• Better education and engaging in physical and mental activities throughout older adulthood slows declines in mental abilities

Cognitive Changes

Social Development

• One theory: older adults gradually “disengage,” from vocational, social, and relationship roles as they face the prospect of their lives ending

• Activity theory of aging: life satisfaction in late adulthood highest when maintain previous level of activity

• Well-being in old age includes achieving what Erik Erikson called ego integrity—the feeling that one’s life has been meaningful

• Despair is experienced by those who are filled with regrets or bitterness about mistakes, missed opportunities, or bad decisions

Final ChapterIn general, anxiety about dying peaks in middle adulthood, tends to decrease in late adulthood

Denial

Anger

Bargaining

Depression

Acceptance

Kübler-Ross’s stages of dying

These stages are not universally

demonstrated

Parenting Styles

• Demanding but unresponsive to their children’s needs or wishes

Authoritarian parenting style

• Permissive-indulgent parents are responsive, warm, and accepting of their children, but impose few rules and rarely punish their children

• Permissive-indifferent parents are both unresponsive and uncontrolling

Permissive parenting styles

• Warm, responsive, and involved with their children; set clear standards for mature, age-appropriate behavior; and expect their children to be responsive to parental demands

• This is the style that is associated with a broad range of beneficial effects for the adolescent, such as higher grades and better confidence

Authoritative parenting style

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.