In Piaget's preoperational stage, children typically fail to conserve because of which concept?

• A. Egocentrism
• B. Centration
• C. Reversibility
• D. Object permanence

Answer: (B)

Centration explains why children in the preoperational stage struggle with conservation. They tend to focus on one perceptual feature at a time, usually the most striking aspect of the situation. In a liquid-conservation task, they fixate on the height of the liquid in a tall, narrow glass and ignore the width, so they believe the taller glass contains more even though the amounts are equal. This single-dimension focus prevents them from recognizing invariants like volume or mass across surface changes.

As children develop into the concrete operational stage, they gain decentering—the ability to consider multiple dimensions—and reversibility, so they can imagine transforming the situation back to its original state and see that the quantity remains the same.

Egocentrism is about viewing the world from one’s own perspective, not about preserving quantity. Object permanence concerns understanding that objects continue to exist when hidden, which appears earlier in development. Reversibility is related to this process but is not the sole reason for the conservation error; centration is the core obstacle in the preoperational period.