Birth to 2 years
The child experience the world through their five senses. She learns to differentiate herself from objects. The child learns that things continue to exist even when they are not present. The child is 'egocentric', meaning the child is not capable of viewing the world from any point of view but their own.
2 years to 7 years
Thinking is still egocentric. The child learns to use language to represent objects. The child understands rules, although not why the exist and do not see them as modifiable.
7 years to 11 years
The child can think logically about objects and events. Can begin to understand different points of view. Understands why rules exist.
11 years and up
The child can think logically about the abstract. They can think about the hypothetical, the future, and ideological problems. They can form and test hypotheses.
Critics of Piaget believe that some children advance much faster to concrete and formal thought.
Robbins, S.P., Chatterjee, P., & Canda, E.R. (2006). Contemporary human behavior theory: A critical perspective for social work (2nd ed.). Boston: Pearson.