Early Theories of human Development

• The scientific study of children began in the late 19th century and flourished in the early 20th century.
• Pioneering psychologists aimed to understand human behavior through the study of its development.
• William Shakespeare's "seven ages of man" included stages of childhood and adulthood.

Early Theories of Development

• John Locke, Jean-Jacques Rousseau, and Charles Darwin proposed theories that are the basis for developmental psychology.
• Locke was a British empiricist who believed the mind of a newborn is a tabula rasa ("blank slate").
• Locke thought knowledge is written on the mind through experience and learning.
• Rousseau proposed a nativistic model where development occurs through innate processes, progressing through stages of infancy, childhood, and adolescence.
• Rousseau's ideas influenced educators.
• Darwin's theory of evolution led to the suggestion that development proceeds through evolutionary recapitulation.
• Human behaviors originate in successful adaptations from the past where "ontogeny recapitulates phylogeny."

G. Stanley Hall

• G. Stanley Hall was influenced by Darwin's theories, believing children developed similarly to how a species evolved.
• Hall focused on childhood development, adolescence, and evolutionary theory.
• Hall taught the first courses in child development, and his students became leading researchers.
• Hall established scientific journals for child development research.
• Hall was the first president of the American Psychological Association.

James Mark Baldwin

• James Mark Baldwin (1861-1934) was an American philosopher and psychologist who researched infant development.
• Baldwin contributed to early psychology, psychiatry, and the theory of evolution.
• Baldwin's writings, such as “Mental Development in the Child and the Race," influenced Jean Piaget and Lawrence Kohlberg.

John B. Watson

• John Watson wrote "Psychological Care of Infant and Child" in 1928 to clarify behaviorist views on child care and development.
• Watson founded behaviorism, which emphasizes the role of nurture in human development.
• Watson believed human behavior is based on experiences and learning.
• Watson thought all behaviors are learned, or conditioned, such as the "Little Albert" study, where an infant was conditioned to fear a white rat.
• Watson advised treating children as young adults with respect but without emotional attachment, warning against too much love and affection.
• Watson explained that love is conditioned.
• Watson's book was criticized but promoted more research into early childhood behavior and development.

Sigmund Freud

• Sigmund Freud's model of "psychosexual development" came from his psychoanalytic approach to personality and psychopathology.
• Freud based his model on his and his patients’ recollections of their childhood.
• Freud developed a stage model where the child's libido focuses on different zones of the body as they grow.
• Freud's model is interactionist, believing that successful personality development depends on experiences during each biologically determined stage.
• Freud's emphasis on the importance of early childhood experiences has had a lasting impact.

Arnold Gesell

• Arnold Gesell, a student of G. Stanley Hall, conducted the first large-scale detailed study of children’s behavior.
• Gesell's research showed consistent patterns of development, supporting the view that human development depends on biological maturation.
• The environment only provides minor variations in the age at which skills emerge.
• Gesell's research produced norms for early behaviors like sitting, crawling, and walking.
• Gesell developed observational techniques, including one-way viewing screens and recording methods.

Jean Piaget

• Jean Piaget (1896-1980) is considered influential for his stage theory of cognitive development.
• Piaget's work inspired more research than any other theorist, and many of his concepts are foundational to developmental psychology.
• Piaget was interested in children’s knowledge, thinking, and qualitative differences in thinking as it develops.
• Piaget called his field "genetic epistemology," stressing biological determinism, but assigned importance to experience.
• Children "construct" knowledge through "assimilation," evaluating new information based on existing knowledge, and "accommodation," modifying cognitive structures based on new experiences.

Modern Developmental Psychology

• Modern developmental psychology focuses on how and why certain modifications throughout an individual’s life-cycle (cognitive, social, intellectual, personality) and human growth change over time.
• Erik Erikson developed a model of eight stages of psychological development and believed that humans developed in stages throughout their lifetimes, affecting their behaviors.

Developmental psychology emerged from late 19th and early 20th century efforts to understand behavior through development. Philosophers like Locke emphasized experience, while Rousseau highlighted innate processes. Darwin's evolution theory suggested development mirrors evolutionary stages.