Which of the following is NOT a Piaget stage of cognitive development?

• A. Sensorimotor
• B. Postoperational
• C. Preoperational
• D. Formal Operational

Answer: (B)

Piaget’s theory maps cognitive development onto four distinct stages, each with its own way of thinking. In the earliest stage, infants learn about the world through actions and senses and gradually develop object permanence. The next stage brings symbolic thought and language, but logical operations like conservation haven’t developed yet. Then comes a period where children start to think logically about concrete objects, understand conservation, and classify but still struggle with abstract ideas. The final stage introduces abstract and hypothetical reasoning, allowing systematic problem-solving. The term that isn’t part of Piaget’s sequence is postoperational; Piaget didn’t include a postoperational stage—his stages end with formal operational. In some later theories, “postformal” thinking is discussed, but that sits outside Piaget’s framework.