Jean Piaget
"He was a Swiss developmental psychologist and philosopher known for his epistemological studies with children. His theory of cognitive development and epistemological view are together called "genetic epistemology
Stages of Development
Piaget (1952) believed that these stages are universal for example; that the same stage of development occurs in children all over the world, whatever their culture.
Stage of Development Key Feature Research Study
Sensorimotor
0 - 2 yrs. Object Permanence Blanket & Ball Study
Preoperational
2 - 7 yrs. Egocentrism Three Mountains
Concrete Operational
7 – 11 yrs. Conservation Pendulum Task
Formal Operational
11yrs + Manipulate ideas in head, e.g. Abstract Reasoning Conservation of Number