Ch. 9

Lifespan Development

What is Developmental Psychology?

Developmental psychology is the scientific study of how and why human beings change over the course of their life. It examines patterns of growth and change in physical, cognitive, moral, and social domains from conception to death.

• Physical development: Changes in body structure and function.

• Cognitive development: Changes in thinking, problem-solving, and information processing.

• Moral development: Changes in understanding of right and wrong.

• Social development: Changes in relationships and social skills.

Major Issues in Developmental Psychology

Three major debates shape the study of development:

• Nature vs. Nurture: The extent to which genetic inheritance (nature) and environmental experiences (nurture) influence development.

• Continuity vs. Stages: Whether development is a gradual, continuous process or occurs in distinct stages.

• Stability vs. Change: Whether early personality traits persist or change throughout life.

Research Methods in Developmental Psychology

Researchers use several methods to study development over time:

• Cross-sectional research: Compares individuals of different ages at one point in time.

• Longitudinal research: Follows the same individuals over an extended period.

• Cross-sequential research: Combines cross-sectional and longitudinal approaches by studying several groups over time.

Early Stages of Development

Prenatal Development

Prenatal development occurs in three main stages:

• Germinal Stage (0-2 weeks): Begins at fertilization; the zygote divides and implants in the uterine wall.

• Embryonic Stage (2-8 weeks): Major organs and structures develop; embryo is about 1 inch long at 8 weeks.

• Fetal Stage (8 weeks-birth): Period of rapid growth; organs become functional, and the fetus responds to external stimuli.

Teratogens are substances (drugs, chemicals, viruses) that can cross the placenta and harm the developing fetus, especially during critical periods.

• Nutrition: Severe malnutrition increases risk of complications and neurological deficits.

• Stress and Emotion: Maternal anxiety and depression can have long-lasting effects on the child.

Infancy

• Reflexes: Infants are born with survival reflexes such as grasping, Moro (startle), rooting, stepping, and sucking.

• Motor Development: Progresses from raising head/chest (2-4 months), rolling over (2-5 months), sitting with/without support (4-7 months), crawling (7-8 months), to walking (8-18 months).

• Sensory Development: Most senses are well developed at birth except vision.

• Brain Development: Synaptic pruning eliminates unused synapses, occurring from infancy until sexual maturation.

Developmental Theories

Piaget's Theory of Cognitive Development

Jean Piaget proposed that children progress through four stages of cognitive development:

• Sensorimotor Stage (0-2 yrs): Understanding the world through senses and actions; development of object permanence.

• Preoperational Stage (2-7 yrs): Intuitive thinking, egocentrism, centration, lack of conservation and reversibility.

• Concrete Operational Stage (7-11 yrs): Logical operations, conservation, reversibility, classification; no abstract thought.

• Formal Operational Stage (12+ yrs): Abstract and hypothetical reasoning; can reason contrary to experience.

Key Terms:

• Schema: Mental concept formed by children as they experience new situations.

• Assimilation: Fitting new information into existing schemas.

• Accommodation: Modifying schemas to fit new information.

Criticisms: Piaget may have underestimated young children's abilities.

Vygotsky’s Sociocultural Theory

• Scaffolding: Children learn with help from adults or older children; support is gradually removed.

• Zone of Proximal Development (ZPD): Difference between what a child can do alone and what they can do with help.

Language Development

• Cooing (2 months): Making vowel sounds.

• Babbling (6 months): Repeating consonant-vowel combinations.

• One-Word Speech (1 yr): Single words to express whole ideas.

• Telegraphic Speech (1.5 yrs): Short, simple sentences.

• Whole Sentences (Fluent by 6 yrs): Complex sentences; 75% intelligible by age 4.

Social and Emotional Development

Attachment

Attachment is a close emotional bond between an infant and caregiver. Mary Ainsworth's Strange Situation Experiment identified four types:

Type	Description
Secure (≈70%)	Cry at departure, greet mother happily at arrival, use mother as base
Avoidant (≈20%)	Do not cry at departure, avoid mother at arrival, anger and seek support
Ambivalent (≈10%)	Anxious before mother leaves, very upset at departure, contact at arrival but show resistance
Disorganized/Disoriented	Inconsistent, contradictory behaviors; confusion

Benefits of Secure Attachment: Larger vocabularies, curiosity, competence, better friendships, and secure relationships in adulthood (correlational data).

Erikson’s Theory of Psychosocial Development

Erik Erikson proposed eight stages, each with a psychosocial crisis:

Stage	Age	Crisis	Key Question
Trust vs. Mistrust	Birth-1.5 yrs	Trust in caregivers	Can I trust the people around me?
Autonomy vs. Doubt	1.5-3 yrs	Independence	Can I do things myself?
Initiative vs. Guilt	3-6 yrs	Initiative	Am I good or bad?
Competence vs. Inferiority	6-11 yrs	Competence	How can I be good?
Identity vs. Role Confusion	Adolescence	Identity	Who am I?
Intimacy vs. Isolation	Young adulthood	Intimacy	Will I be loved or alone?
Generativity vs. Stagnation	Middle adulthood	Contribution	How can I contribute to the world?
Integrity vs. Despair	Late adulthood	Reflection	Did I live a meaningful life?

Criticisms: Theory is broad and not easily testable.

Parenting Styles

Style	Description	Impact
Authoritarian	Strict rules, controlling, physical discipline	Insecurity, withdrawal, resentment, rebellion
Permissive-Neglectful	Lack of involvement	Selfishness, poor social skills
Permissive-Indulgent	No limits, child can do no wrong	Selfishness, poor social skills
Authoritative	Clear limits, love, democratic, non-physical punishment	Self-reliance, independence

Later Stages of Development

Adolescence

• Transition from childhood to adulthood (13-early 20s).

• Puberty: Physical changes as sexual development peaks; lasts about 4 years.

Adolescence and Morality

Lawrence Kohlberg identified three levels of moral development:

• Preconventional: Morality based on rewards and punishments.

• Conventional: Morality based on societal rules and approval.

• Postconventional: Morality based on personal principles and conscience.

Aging

• Begins in early 20s and continues to death.

• Physical changes: Menopause (women), andropause (men), increased health problems, slower reaction time.

• Cognitive decline: Decrease in semantic and episodic memory with age.

• Happiness and Age: Positive affect tends to remain stable or increase, while negative affect may decrease with age.

Expectation/Experience	Adults 18-64 (%)	Adults 65+ (%)
Memory loss	57	25
Able to drive	45	11
Serious illness	42	21
Sexually active	33	22
Depressed	29	20
Reading needed	29	9
Loneliness	--	--
Paying bills	24	16
Being a burden	2	--

Healthy Aging: Increased activity, social interactions, independence, close family ties, and acceptance of aging promote successful aging.

Additional info: Some content was inferred and expanded for clarity and completeness, including definitions, examples, and table formatting.