Jean Piaget

Jean Piaget was a psychologist who developed the Theory of Cognitive Development.

Piaget was born in Switzerland in the late 1800s and was a precocious student, publishing his first scientific paper when he was just 11 years old. His early exposure to the intellectual development of children came when he worked as an assistant to Alfred Binet and Theodore Simon as they worked to standardize their famous IQ test.

Much of Piaget's interest in the cognitive development of children was inspired by his observations of his own nephew and daughter. These observations reinforced his budding hypothesis that children's minds were not merely smaller versions of adult minds.

Up until this point in history, children were largely treated simply as smaller versions of adults. Piaget was one of the first to identify that the way that children think is different from the way adults think.

Instead, he proposed, intelligence is something that grows and develops through a series of stages. Older children do not just think more quickly than younger children, he suggested. Instead, there are both qualitative and quantitative differences between the thinking of young children versus older children.

Based on his observations, he concluded that children were not less intelligent than adults, they simply think differently. Albert Einstein called Piaget's discovery "so simple only a genius could have thought of it."

Piaget's stage theory describes the cognitive development of children. Cognitive development involves changes in cognitive process and abilities.  In Piaget's view, early cognitive development involves processes based upon actions and later progresses to changes in mental operations.