What cognitive skill is developed when children learn to conserve weight, mass, and numbers?

• A. Abstract reasoning
• B. Operational thought
• C. Object permanence
• D. Symbolic representation

Answer: (B)

The development of the skill to conserve weight, mass, and numbers is related to the cognitive developmental stage described by Jean Piaget, particularly during the concrete operational stage. This concept is specifically identified as "operational thought," which refers to the ability of children to perform mental operations and understand the properties of objects.

When children learn to conserve, they understand that certain properties of objects (such as weight, mass, and quantity) do not change even when their form or arrangement does. For instance, if you have two equal balls of clay and one is flattened, a child who has developed operational thought understands that the amount of clay remains the same despite the change in shape. This ability to reason logically about the properties of objects is a key characteristic of operational thought and marks a significant cognitive development in children, enabling them to think more systematically and manage more complex problem-solving tasks.

In contrast, other options like abstract reasoning involve higher-level thinking that develops later, while object permanence pertains to understanding that objects continue to exist even when not seen—an earlier developmental milestone. Symbolic representation refers to a child's ability to use symbols (like words or images) to represent concepts, which, while important, is not directly linked to the conservation tasks at this developmental stage.