What cognitive development concept describes a child's belief that quantities remain constant despite changes in shape?

The concept that describes a child's belief that quantities remain constant despite changes in shape is known as conservation. This principle is an essential part of cognitive development theory and is typically developed during the concrete operational stage, which occurs roughly between the ages of 7 and 11 years, according to Jean Piaget's stages of cognitive development.

Conservation demonstrates a child's ability to understand that certain properties of objects, such as volume, mass, and number, remain the same even when they are transformed in shape or arrangement. For example, when water is poured from a tall, narrow glass into a short, wide glass, a child who has developed the concept of conservation will understand that the amount of water remains unchanged despite the alteration in the shape of the container.

This understanding contrasts with earlier stages of development, where children may focus more on the immediate perceptions of an object rather than its underlying properties. Thus, conservation reflects a more advanced cognitive ability to grasp the permanence of quantity independent of visual changes.