concrete operational

Meaning: In Piaget's theory, the concrete operational stage follows the preoperational stage and precedes the formal operational stage. The child can now use mental operations, which are logical rules that can be run in the mind, but only on things that are real or easy to picture. Key abilities include conservation (number, mass, volume), reversibility (an action can be undone mentally), decentration (tracking several features at once, such as height and width), classification, seriation (ordering by size), and much less egocentrism.

On the MCAT: A typical passage shows water poured from a short, wide glass into a tall, thin one. A child who says the tall glass holds more is preoperational. A child who says the amount is the same, because nothing was added or removed or because it could be poured back, is concrete operational. Questions may also ask you to name the stage from a described behavior, or to say what a child at this stage cannot yet do.

Common confusion: Students mix this stage up with its neighbors. Failing conservation points to preoperational. Handling abstract, hypothetical or purely verbal problems points to formal operational. Concrete operational thinking is logical but tied to tangible examples. Age ranges are approximate, and children move between stages at different times.