At what stage does the concept of conservation develop?

The concept of conservation develops during the concrete operational stage, which occurs roughly between the ages of 7 and 11. At this stage, children begin to understand that certain properties of objects, such as volume or number, remain the same despite changes in form or appearance. For example, a child recognizes that the amount of liquid in a tall, narrow glass is the same as that in a short, wide glass, even though the shapes of the containers are different.

This understanding marks a significant cognitive transition from the preoperational stage, where children are typically egocentric and cannot yet grasp the concept of conservation. They often focus on the appearance of objects rather than their underlying properties. The concrete operational stage allows for logical thinking about concrete events and objects, laying the groundwork for further cognitive development. The formal operational stage comes later and involves abstract thinking, while the sensorimotor stage focuses on learning through sensory experiences and motor activities, before any understanding of conservation can take place.