Developmental psychology
Historical antecedents

Jean-Jacques Rousseau and John B. Watson are typically cited as providing the foundation for modern developmental psychology. In the mid-18th century, Jean Jacques Rousseau described three stages of development: infants (infancy), puer (childhood) and adolescence in Emile: Or, On Education. Rousseau's ideas were adopted and supported by educators at the time.

Developmental psychology generally focuses on how and why certain changes (cognitive, social, intellectual, personality) occur over time in the course of a human life. Many theorists have made a profound contribution to this area of psychology. One of them, Erik Erikson developed a model of eight stages of psychological development. He believed that humans developed in stages throughout their lifetimes and that this would affect their behaviors.

In the late 19th century, psychologists familiar with the evolutionary theory of Darwin began seeking an evolutionary description of psychological development; prominent here was the pioneering psychologist G. Stanley Hall, who attempted to correlate ages of childhood with previous ages of humanity. James Mark Baldwin, who wrote essays on topics that included Imitation: A Chapter in the Natural History of Consciousness and Mental Development in the Child and the Race: Methods and Processes, was significantly involved in the theory of developmental psychology. Sigmund Freud, whose concepts were developmental, significantly affected public perceptions.
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