Development Through the Life Span

Chapter 3: Developing Through the Life Span

Chapter Overview

  • Developmental Psychology’s Major Issues

  • Prenatal Development and the Newborn

  • Infancy and Childhood

  • Adolescence

  • Adulthood

Major Issues in Developmental Psychology

  • Nature and Nurture

    • Discusses the interaction between genetic inheritance (nature) and experiences (nurture) influencing development.

  • Continuity and Stages

    • Questions whether parts of development are gradual/continuous or change abruptly in distinct stages.

  • Stability and Change

    • Examines which traits persist throughout life and how individuals change as they age.

Research Methods in Developmental Psychology

  • Developmental psychologists study these issues through:

    1. Longitudinal Studies: Observing the same individuals over time to track changes.

    2. Cross-Sectional Studies: Comparing individuals at different ages to identify developmental differences.

Developmental Theories

  • Continuous Development Theories:

    • Development is viewed as a gradual, ongoing process of change.

  • Stage Theories:

    • Development is believed to progress through distinct, qualitatively different stages.

Key Stage Theorists

Lawrence Kohlberg: Moral Development

  • Preconventional Morality: Moral reasoning based on consequences.

Erik Erikson: Psychosocial Development

  • Stages include:

    • Basic Autonomy

    • Trust

    • Initiative

    • Competence

Jean Piaget: Cognitive Development

  • Stages include:

    • Sensorimotor: Birth to nearly 2 years

    • Preoperational: 2 to 6 or 7 years

    • Concrete Operational: 7 to 11 years

    • Formal Operational: 12 years through adulthood

Stability and Change

  • Evidence shows both stability and change in personality traits:

    • Stability: Temperament is a stable trait, e.g., inhibited toddlers often become introverted adults (Tang et al., 2020).

    • Change: Traits such as conscientiousness and agreeableness tend to increase with age (Roberts et al., 2006). Risk-taking behavior declines with age due to brain development (Mata et al., 2016).

Prenatal Development and the Newborn

  • Chromosomes: Thread-like structures of DNA containing genes.

  • DNA (deoxyribonucleic acid): The molecule housing genetic information.

  • Genes: Segments of DNA that can be active (expressed) or inactive.

  • Small DNA Variations: Help explain individual differences and traits such as height or susceptibility to illness (Ellinghaus et al., 2020).

    • Traits are often polygenic, influenced by multiple genes (Plomin et al., 2016).

    • Example: Depression linked to 269 genes (Howard et al., 2019).

Interaction of Heredity and Environment

  • Both heredity and environment shape human differences.

    • Environmental Influences:

    • Maternal nutrition in the womb

    • Social support throughout life

    • Diet affecting height

  • Heredity and environment interact in significant ways:

    • Example:

    • Malia is genetically sociable → attracts attention → becomes outgoing.

    • Kalie is genetically shy → gets less attention → becomes withdrawn.

  • Epigenetics: Refers to how environment and lifestyle can activate or deactivate genes without altering the DNA sequence.

  • An example of epigenetic change includes the effects of famine in British India affecting the health risk of descendants (e.g., diabetes, obesity).

Stages of Prenatal Development

  1. Zygote: The fertilized egg that undergoes rapid cell division in the first two weeks.

  2. Embryo: The developing human organism from about two weeks to eight weeks post-fertilization.

  3. Fetus: The developing organism from nine weeks after conception to birth.

Prenatal Hazards

  • Teratogens: Agents (chemical or viral) that can harm the embryo or fetus.

  • Fetal Alcohol Syndrome (FAS): Results in physical and mental deficits in children due to maternal alcohol consumption during pregnancy.

The Competent Newborn

  • Newborns exhibit automatic reflex responses aiding survival:

    • Seeking sights and sounds linked to humans, especially the mother.

    • Have well-developed senses and reflexes (rooting, sucking, startle, grasping).

    • Display a biologically rooted temperament: variations include calmness or strong reactions to stimuli.

Types of Twins

  • Identical (monozygotic) Twins: Result from a single fertilized egg splitting into two, leading to genetically identical siblings.

  • Fraternal (dizygotic) Twins: Develop from two distinct fertilized eggs.

Twin and Adoption Studies

  • These studies inform research on heredity vs. environment.

    • Identical twins share 100% of genes, while fraternal twins share 50%.

    • Findings from 15 million twin pairs indicate identical twins exhibit greater similarity in:

    • Personality

    • Abilities and interests

    • Emotional traits and behaviors (Polderman et al., 2015).

Infancy and Childhood: Maturation and Physical Development

  • Maturation: A lifelong process of growth and development driven by biological and genetic factors.

  • Brain and nervous system development:

    • Neural networks grow rapidly post-birth; enriched environments boost brain power.

    • Critical Period: Some skills must be developed during specific time frames, such as language, but brain development continues beyond childhood.

Motor Development

  • Motor Skills: Develop as muscles and the nervous system mature.

    • Sequence is generally universal: sitt\ng, crawling, walking, running; with variations in timing influenced by cultural factors.

    • Example: in the U.S., 90% of babies walk by 15 months; additional support in other cultures may accelerate this process.

Cognitive Development: Piaget

  • Piaget’s theory emphasizes cognitive development occurs through stages:

    • Children as active thinkers evolving understanding.

    • Schema: A framework for organizing and interpreting information.

    • Assimilation: Integrating new experiences into existing schemas.

    • Accommodation: Adjusting schemas in response to new experiences.

Piaget's Stages of Cognitive Development

  1. Sensorimotor Stage (Birth to nearly 2 years):

    • Development of object permanence; awareness that objects continue to exist when not perceived.

  2. Preoperational Stage (2 to 6/7 years):

    • Development of language and symbolic thought; egocentrism is prevalent.

  3. Concrete Operational Stage (7 to 11 years):

    • Grasping concrete analogies and performing arithmetic operations; understanding conservation.

  4. Formal Operational Stage (12 years and beyond):

    • Abstract reasoning and logical thought develop.

Reflecting on Piaget’s Theory

  • Recognizes important cognitive milestones and has prompted widespread interest in cognitive development.

  • Contemporary research suggests cognitive development is more continuous than Piaget proposed.

Vygotsky’s Alternative Viewpoint

  • Focuses on the role of social interaction in cognitive development:

    • Scaffolding: Temporary support allowing higher-level thinking.

    • Language promotes social mentoring, fostering cognitive skills.

  • Internal Speech: Supports thought processes.

Theory of Mind (ToM)

  • The ability to understand that others have thoughts, beliefs, and perspectives that differ from one’s own.

    • Develops around ages 4-5.

    • Younger children’s egocentrism limits their understanding of others’ thoughts.

  • False Belief Tests: Such as Sally-Anne test, highlight differences in understanding in typical vs. autistic development.

Infancy and Childhood: Social Development

  • Stranger Anxiety: Common infant fear beginning around 8 months; infants recognize familiar faces.

  • Attachment: Emotional bond with caregivers. Infants seek closeness and display distress upon separation.

Harlow’s Monkeys Experiment

  • Investigated attachment through a study of infant monkeys with two types of artificial mothers:

    • One made of wire providing milk, one soft and cloth for comfort.

    • Monkeys displayed a preference for the cloth mother, emphasizing the importance of comfort in attachment.

Attachment Theory: John Bowlby

  • Secure Attachment: Infants explore comfortably in the caregiver's presence, show distress when separated, and seek contact upon return.

    • Approx. 60% of infants have secure attachments as a result of responsive caregiving.

  • Insecure Attachment: Includes anxious attachment (crying when separated) and avoidant attachment (ignoring caregiver).

  • Disorganized Attachment: Confused behavior often linked to a history of abuse.

Attachment Styles and Later Relationships

  • Securely attached children develop basic trust and have healthier adult relationships.

    • Anxious attachment seekers tend to need reassurance in relationships.

    • Avoidant styles lead to reduced commitment and increased conflict in relationships.

Parenting Styles

  • Parenting styles can be described through the level of responsiveness and demands placed on children:

    1. Authoritarian: Coercive and demanding.

    2. Permissive: Unrestrained and lenient.

    3. Neglectful: Uninvolved and inattentive.

    4. Authoritative: Confrontive yet responsive, encouraging open discourse.

Outcomes of Parenting Styles

  • Authoritarian style: Linked to low social skills and self-esteem; brain overreactivity to mistakes.

  • Permissive style: Associated with aggression and immaturity.

  • Neglectful style: Results in poor academic and social outcomes.

  • Authoritative style: Linked to the highest self-esteem, self-regulation, and social competence.

Cultural Influences on Child-Rearing

  • Cultural values fluctuate over time and across locations; different child-rearing systems have yielded thriving children in varied contexts.