At what stage do children typically demonstrate conservation?

Children typically demonstrate conservation during the concrete operational stage of cognitive development, which usually occurs between the ages of 7 and 11. Conservation refers to the understanding that certain properties of objects, such as volume, mass, or number, remain the same even when their form or appearance changes.

During the concrete operational stage, children begin to think logically about concrete events. They can perform operations that are reversible, which allows them to understand that changing the shape of a substance does not change its quantity. For example, if liquid is poured from a short, wide cup into a tall, narrow cup, a child who has developed conservation will know that the amount of liquid remains the same despite its different appearance.

This ability to understand conservation marks a significant cognitive advancement from the previous preoperational stage, where children are often fooled by appearances and may think that a taller glass holds more liquid simply because it is taller. The capacity for logical reasoning and understanding of conservation is foundational for further cognitive development that occurs in later stages.