Human Development

Developmental Psychology Overview

  • Study of how behavior and mental processes change over time.
  • Investigates individual differences: why people develop at varying rates or trajectories.
  • Challenges in examining human development include:
    • Post hoc fallacy.
    • Bidirectional influences.

Post Hoc Fallacy

  • Definition: The incorrect assumption that if event A happens before event B, then A must have caused B.
    • Example: "I started drinking green smoothies, and then my grades improved."
  • A common issue in developmental psychology as it involves analyzing effects over time.

Bidirectional Influences

  • Definition: Development arises from continuous reciprocal interactions between individuals and their environment.
    • Example: Parents influence children through parenting style and resources, while children influence parents through behavior and needs.
  • As individuals age, they can increasingly choose their own environments.

Designs in Developmental Psychology

Cross-sectional Design

  • Examines different individuals at different ages simultaneously.
  • Cohorts: Groups defined by being of the same age.
  • Vulnerability: Susceptible to cohort effects, where groups from different time periods may differ systematically.

Longitudinal Design

  • Involves studying the same group of individuals multiple times over an extended period.
  • Advantages:
    • Allows assessment of individual change.
  • Disadvantages:
    • More costly, time-consuming, and vulnerable to attrition (loss of participants).

Influence of Early Experience

  • Early life experiences play a crucial role in development, but later experiences continue to influence throughout life.
  • Misconceptions to avoid:
    • Infant determinism: The idea that early experiences are profoundly influential.
    • Childhood fragility: The notion that children are very vulnerable to stress.
  • Development continues to evolve through childhood, adolescence, and adulthood; children show resilience (e.g., ability to recover from adversity).

Nature-Nurture Debate

  • Both genetic (nature) and environmental (nurture) influences are significant.
    • Gene-environment interaction: Difference in behavior based on environmental context, e.g., a genetically anxious child fares differently in a calm home vs a stressful one.
    • Nature via nurture: Genetic predispositions can lead to the selection or creation of specific environments.
    • Gene expression: Some genes activate in response to particular environmental conditions.

Conception & Prenatal Development

  • Most dramatic changes occur during prenatal development. Following conception, a zygote forms when a sperm fertilizes an egg. Development involves three stages:
    1. Germinal Stage: The zygote divides to form a blastocyst, which grows for the first week and a half after fertilization.
    2. Embryonic Stage: (Week 2-8) The blastocyst develops into an embryo, with formation of limbs, facial features, and major organs.
    3. Fetal Stage: (From week 9 onward) Major organs develop, and physical maturation continues.

Obstacles to Development

  • Teratogens: Environmental agents that negatively impact prenatal development (e.g., smoking, drugs, alcohol).
  • Genetic disorders: Such as Down syndrome can adversely affect development.
  • Prematurity: Being born before 36 weeks increases the risk of complications; longer time in utero reduces risks.

Infant Motor Development

  • Infants exhibit automatic motor behaviors (reflexes) essential for survival, such as sucking and rooting reflexes.
  • Major motor development milestones include:
    • Sitting up.
    • Crawling.
    • Unsupported standing.
    • Walking.

Physical Development in Childhood & Adolescence

  • Dramatic physical changes occur in childhood and adolescence; different body parts grow at varying rates.
  • Puberty marks the transition to adulthood, influenced by hormonal changes (estrogens and androgens).

Physical Development in Adolescence

  • Emergence of:
    • Primary sex characteristics: Reproductive organs and genitals.
    • Secondary sex characteristics: Traits like breast development in females and voice deepening in males.

Physical Development in Adulthood

  • Most individuals reach physical peak in early 20s (strength, coordination, cognitive processing speed).
  • Physical declines begin in middle adulthood, affecting muscle tone, sensory processes, and fertility.

Theories of Cognitive Development

  • Several theoretical frameworks explain how humans learn, think, communicate, and remember:
    • Differences include:
    • Stage-like vs. gradual changes.
    • Domain-general vs. domain-specific.
    • Principal learning sources (physical experience, social interaction, biological development).

Jean Piaget’s Theory of Cognitive Development

  • A Swiss psychologist known for the first comprehensive account of cognitive development.
  • Proposed a stage-like theory focusing on logical reasoning about hypothetical problems.

Key Concepts of Piaget’s Theory

  • Equilibration: The balance achieved between experiences and thoughts.
  • Assimilation: Absorbing new information into existing knowledge structures.
  • Accommodation: Altering beliefs to align with new experiences when assimilation is insufficient.

Piaget’s Stages of Development

  1. Sensorimotor Stage: (Birth to 2 years)
    • Focused on immediate physical experiences; no thought beyond this; lacks object permanence and deferred imitation.
  2. Preoperational Stage: (2 to 7 years)
    • Capable of mental representations but egocentric and lacks conservation (understanding quantity remains the same despite changes in shape or appearance).
  3. Concrete Operations Stage: (7 to 11 years)
    • Can perform mental operations but only with concrete objects, limited in abstract reasoning.
  4. Formal Operations Stage: (11 years to adulthood)
    • Ability to reason hypothetically and abstractly, understanding logical concepts.

Pros & Cons of Piaget's Theory

Advantages

  • Highly influential, changed perceptions of children's cognitive development.
  • Emphasizes active learning processes.
  • Offers a parsimonious explanation of cognitive development.

Disadvantages

  • Development may be more domain-specific and continuous rather than stage-like.
  • Methods perceived as culturally biased; mainly based on Western-educated samples.
  • Likely underestimated children’s capabilities during interactions with their environment.

Lev Vygotsky’s Theory of Cognitive Development

  • Focuses on social and cultural influences on learning and cognition.
    • Scaffolding: Parents structure learning environments and gradually remove support as competence increases.
    • Zone of Proximal Development: A learning phase where children can benefit from guided instruction.

Cognitive Landmarks of Early Development

  • Includes insights in perception, memory, and language, along with:
    • Naive Physics: Understanding of how physical objects behave.
    • Object Categorization: Generalizing kinds, e.g., recognizing all birds as similar.
    • Theory of Mind: Developing a sense of self, recognizing differences with others, and understanding varying perspectives.
    • Mathematical Understanding: Grasping concepts like conservation of number.

Cognitive Changes in Adolescence

  • Frontal lobe maturation affects impulse control and risk-taking behaviors.
  • Adolescents may feel unique (personal fable) and begin evaluating knowledge as relative rather than absolute.

Cognitive Function in Late Adulthood

  • Cognitive decline can occur in aspects like free recall and processing speed.
  • However, abilities in cued recall, recognition, vocabulary, and knowledge may remain stable or improve.

Social Development in Infancy & Childhood

  • Infants rapidly develop an interest in others.
  • Stranger Anxiety: Peaks between 12-15 months.
  • Children's social emotional styles reflect their temperaments which tend to be genetically based:
    • Easy: Adaptable and relaxed.
    • Difficult: Fussy and easily frustrated.
    • Slow to warm up: Initially disturbed by new stimuli but gradually adjusts.

Attachment in Social Development

  • Strong emotional bonds with caregivers, crucial for survival and protection.
  • Imprinting concept drawn from animal behavior studies, e.g., young geese following the first large moving object they see.
  • Longitudinal studies indicate early adoption leads to better outcomes; delayed adoption in low-quality care correlates with poorer outcomes.

Contact Comfort

  • Harlow’s research with monkeys highlighted the importance of physical touch over mere nourishment in forming attachment bonds (contact comfort).

Attachment Styles

  • Techniques like the Strange Situation Task categorize infant attachment styles:
    1. Secure: Upset when caregivers leave, joyful upon return.
    2. Insecure-avoidant: Indifferent to caregiver's departure and return.
    3. Insecure-anxious: Panic upon departure, mixed reactions upon return.
    4. Disorganized: Inconsistent responses to departure and return (least common).
  • Attachment styles can predict later behaviors and they exhibit cultural variances.

Parenting Styles in Social Development

  • Influences healthy development:
    1. Permissive: Lenient, affectionate, little discipline.
    2. Authoritarian: Strict, punishing, little affection.
    3. Authoritative: Supportive with clear, firm limits.
    4. Uninvolved: Neglectful and indifferent.
  • Authoritative parenting is associated with the best social and emotional adjustment among children.

Parenting Style Considerations

  • Recent research suggests that as long as basic needs like affection and discipline are met, parenting style might not be as critical.
  • Extreme styles, such as abusive methods or pre-existing genetic predispositions towards problematic behavior have a more significant impact on development.

Social Development in Adolescence

  • Identity formation (defining who we are) is a central challenge.
  • Erikson emphasizes "identity crisis" as a significant feature, with personality growth continuing throughout life via eight distinct psychosocial stages.

Kohlberg's Moral Development

  • Observes how morality matures, exploring responses to moral dilemmas.
  • Morality evolves in three stages:
    1. Preconventional: Based on punishment and reward.
    2. Conventional: Centered on social values.
    3. Postconventional: Focused on internal moral principles.
  • Examples of moral reasoning concerning dilemmas (e.g., stealing to save a life) highlight differences across the stages.

Critiques of Kohlberg's Model

  • Cultural bias exists comparing individualist vs collectivist orientations.
  • Sex bias scrutinizing distinctions between 'justice' and 'caring'.
  • Low correlation of moral reasoning with actual moral behavior.
  • Assumes reasoning precedes emotional reactions to moral issues.

Life Transitions in Adulthood

  • Major changes occur in lifestyle during early adulthood: careers, relationships, and parenting.
  • Adjustments in middle adulthood may include physical changes and family dynamics.
  • Popular myths include the midlife crisis and empty nest syndrome, linked to emotional distress related to aging and children leaving home, respectively.