Book definition: the construction of thought processes, including remembering, problem solving, and decision-making, from childhood through adolescence to adulthood


Jean Piaget first began work his theory of cognitive development after observing his own children's growth. Using this knowledge, he formulated three stages that he believed described every child's cognitive and intellectual maturation.


  1. The Sensorimotor Stage
  2. The Preoperational Stage
  3. The Concrete Operational Stage