Developmental Psychology - Infant Development

Developmental Psychology

• Focuses on how and why biological, physical, cognitive, emotional, and social abilities develop throughout childhood.
• Key debates include stability vs. change, continuity vs. discontinuity, nature vs. nurture, and critical vs. sensitive periods.
• Studying development helps understand adult minds, clinical conditions, and childhood abilities.

Infant Development

• Human development begins in utero.
• Gestation period is roughly 38-40 weeks (9 months).
• Infant brains are structurally similar to adult brains but are smaller (about a quarter the size).
• By 6 months, the brain reaches about 50% of its adult size.

Infant Development - Before Birth

• Brain neurons are not fully myelinated or connected at birth.
• Myelination and synaptogenesis (formation of synapses) continue until around 2 years old.
• Unused synapses are pruned throughout development.
• Neural plasticity (brain's ability to form and maintain synapses) decreases with age.

Infant Development - Prenatal Damage & Teratogens

• Damage can occur to an infant brain before birth.
• Teratogens are substances that cause atypical development if present during prenatal exposure.
• Exposure to harmful substances (e.g. Teratogens) during pregnancy negatively impacts development.
• Examples include air pollution (leading to genetic mutations, per Perera et al, 2002) and PVC exposure (leading to shorter pregnancies and early delivery, per Latini et al, 2003).
• Fetal alcohol spectrum disorders (FASD) can result from prenatal alcohol exposure.

FASD Cognitive and Behavioral Impairments

• Infancy: Slower reaction times.
• Preschool: Decreased attention, hyperactivity.
• Childhood: Learning problems, memory deficits.
• Adulthood: Impaired problem-solving and higher rates of substance dependence.

A Brief History of Studying Development

• Increased need for an educated workforce during the Industrial Revolution fueled early research.
• Initial focus was on cognitive development for education.
• Later research explored emotional/social development, and adulthood development.
• Key figures include John B. Watson, Charles Darwin, and Wilhelm Preyer.
• By 1880, 47 empirical studies were conducted across Europe and North America.

Leading Figures in Developmental Psychology

• Jean Piaget (1896-1980): A Swiss child psychologist who proposed a stage theory of cognitive development.
• Also relevant: Sigmund Freud's psychodynamic theory and Erik Erikson's psychosocial theory.

Piaget's Stages of Cognitive Development

• Sensorimotor (0-2 years): Infants sense and move but have limited cognition. Object permanence (understanding objects exist even when unseen) is a key cognitive ability not fully grasped at this stage.
• Preoperational (2-7 years): Egocentrism (inability to see things from another's perspective) is characteristic; children are biased by their perceptions and cannot use operations.
• Concrete Operational (7-12 years): Children can solve concrete problems using operations.
• Formal Operational (12 years +): Systematic, rigorous reasoning and use of hypothetical situations characterize this stage; children can conduct experiments on abstract situations that go beyond their immediate perception.

Key Cognitive Concepts

• Object Permanence: Understanding that objects exist even when out of sight.
• A-not-B Error: Infants persist in searching for an object in a familiar location (A) even after it’s moved to a new location (B). This signifies perseverative reaching.
• Egocentrism: Inability to take another's perspective.
• Conservation: Understanding that changes in appearance do not change underlying properties (e.g., quantity, volume).
• Mental Imagery: Representing objects and events mentally.
• Operations: Logical mental rules to solve problems.
• Constructivism: Children actively build their understanding of the world.