Final answer:
Jean Piaget proposed a theory of cognitive development that involves four stages: sensorimotor, preoperational, concrete operational, and formal operational.
Step-by-step explanation:
Jean Piaget proposed a theory of cognitive development that unfolds in four stages: sensorimotor, preoperational, concrete operational, and formal operational. In the sensorimotor stage (birth to about 2 years old), infants learn about the world through their senses and motor behavior.
The preoperational stage (2 to 7 years old) is characterized by symbolic thinking and egocentrism. In the concrete operational stage (7 to 11 years old), children develop logical reasoning skills and understand conservation. Finally, in the formal operational stage (adolescence and beyond), individuals think abstractly and engage in hypothetical and scientific reasoning.