According to Piaget, when do children first achieve mental operations?

• A. Sensorimotor stage
• B. Preoperational stage
• C. Concrete operational stage
• D. Formal operational stage

Answer: (A)

Mental operations are internal, reversible thinking processes that let a child manipulate information in the mind rather than acting it out physically. Piaget assigns the first appearance of these operations to the concrete operational stage, typically around ages 7 to 11. At this point children can reason about concrete objects and events in a logical way: they understand conservation (the amount stays the same even if its appearance changes), they can reverse steps in their minds, they can classify and seriate, and they can consider multiple attributes at once.

Earlier stages don’t yet show this kind of internal, logical manipulation. In the sensorimotor stage thinking is tied to direct actions on the world, and even though object permanence emerges, the child can’t perform mental transformations. In the preoperational stage thinking becomes symbolic and intuitive but remains egocentric and lacks the reversible operations that characterize concrete operational thought. The formal operational stage later introduces abstract and hypothetical reasoning, building on the groundwork laid during the concrete operational period.