The concrete operational stage is one of four main stages within Piaget model for cognitive development. It is begun, according to Piaget, at approximately age 7 or 8 and is normally developed by age 11. The stage is characterized with the acquired ability to perform simple logical operations, conservation or the ability to know that for example if water from a full cup is transfered to another reciptical then it will retain the same quantity (assuming none spills) no matter what shape it is rearranged in. By this stage Piaget stated that they had mastered reversibillity or the awarence that the subtraction of something is reversible by its addition, or vice versa. They no longer have centration or the ability to concentrate only on one "central" attribute such as hieght. No longer is the child limited to the illogical limitations of animism (the belief that all objects are animals and therefore have feelings), egocentrism (related to animism in that the children believe that all things are like them and therefore have feelings as do the children), and artificialism (the belief that all things were created by mankind) of the Preoperational stage. Children during this stage is limited by the lack of abstract thinking which they develop in the Formal operational stage .

The Theory of Cognitive development offered by Jean Piaget is often critisized by more recent psychologist since they underestimated the cognitive skills of younger children and overestimated the abilities of adolescents to adults. However, if you attempted the test of conservation, he conducted- filling a glass of water then transfering the water to another container and asking "what has more water this or an equal glass?", on a child prior to the operational stage they normally will be unable to answer or will answer incorrectly due to, most likely, centration.