A Piagetian-inspired curricula emphasizes a child-centered educational philosophy. His work has been labeled an interactionist as well as a constructivist. His interest in cognitive development came from his training in the natural sciences and his interest in epistemology. He saw cognitive growth as an extension of biological growth and as being governed by the same laws and principles. He argued that intellectual development controlled every other aspect of development - emotional, social, and moral.

Piaget may be best known for his stages of cognitive development. He discovered that children think and reason differently at different periods in their lives. He believed that everyone passed through an invariant sequence of four qualitatively distinct stages. Invariant means that a person cannot skip stages or reorder them. Although every normal child passes through the stages in exactly the same order, there is some variability in the ages at which children attain each stage. The four stages are:

• Sensorimotor (birth to 2 years) - The mental structures are mainly concerned with the mastery of concrete objects.
• Preoperational (2 years to 7 years) - The mastery of symbols takes place.
• Concrete operational (7 years to 11 years) - Children learn mastery of classes, relations, and numbers and how to reason.
• Formal operational (abstract thinking) (11 years and up) - The last stage deals with the mastery of thought.