This theory is a four-stage ladder up which Piaget thought children climbed as they gathered knowledge about the world:
- Sensorimotor (birth to 18-24 months): infants are aware only of their sensations, fascinated by all the strange new experiences their bodies are having. They are like little scientists exploring the world by shouting at, listening to, banging and tasting everything.
- Pre-operational (18-24 months to 7 years): during this stage children can process images, words and concepts but they can’t do anything with them, they can’t yet operate on them. It’s like they’ve acquired the tools of thought, but don’t yet know how to use them. E.g. in maths they can’t understand that 2 x 3 is the same as 3 x 2.
- Concrete operations (7 to 12 years): at this stage children gain the ability to manipulate symbols and objects, but only if they are concrete – abstract operations are still a challenge.
- Formal operations (12 and up): from here on children are able to think in abstract terms about the world. Now they can understand concepts such as the future, values and justice. From around this age children start thinking like adults.