At what developmental stage do children begin to understand the concept of conservation?

The understanding of conservation, which refers to the idea that certain properties of objects, such as volume, mass, and number, remain the same despite changes in their form or arrangement, typically develops during the concrete operational stage of cognitive development.

Children in this stage, approximately ages 7 to 11, begin to think logically about concrete events. They can recognize that even if the appearance of an object changes, its fundamental properties do not. For example, they can comprehend that if water is poured from a short wide glass into a tall thin glass, the amount of water remains the same, even though it looks different. This cognitive leap is significant because it marks a move towards more logical and organized thinking, laying the groundwork for further cognitive development.

In contrast, the other stages mentioned do not encompass the understanding of conservation. During the preoperational stage, children are still primarily egocentric and struggle with the concept of conservation as they focus largely on appearances rather than underlying properties. The formal operational stage involves abstract thinking and hypothetical reasoning but occurs after the mastery of conservation, making it too advanced for this particular concept. The sensorimotor stage is focused on sensory experiences and motor responses, with no capacity for logical reasoning or understanding of conservation concepts.