concrete operational stage

Meaning: This is the third of Piaget's four stages of cognitive development, after the preoperational stage and before the formal operational stage. Children gain mental operations, which are logical rules applied to concrete things they can see or imagine as real. Key gains include conservation (number, mass and volume stay the same despite a change in shape), reversibility (an action can be undone in the mind), decentering (attending to several features at once, such as height and width), classification, seriation (ordering items by size), and a marked drop in egocentrism.

On the MCAT: A typical passage describes a child watching water poured from a short, wide glass into a tall, thin one. A child who says the amounts are equal shows conservation and fits the concrete operational stage. A child who says the tall glass holds more is preoperational, because of centration on height. Questions also ask you to put the stages in order: sensorimotor, preoperational, concrete operational, formal operational.

Common confusion: Students blur this stage with its neighbors. Preoperational children use symbols and pretend play but lack conservation and logical operations. Formal operational thinkers, from about age 12 on in the theory, handle abstract, hypothetical and purely verbal problems. Concrete operational children are logical but depend on concrete referents. The ages are approximate, not fixed cutoffs.