According to Piaget, the second stage of cognitive development is

Jean Piaget proposed a universal sequence of four distinct sequential stages outlining human cognitive development:First Stage: Sensorimotor Stage (Birth to $2\text{ years}$)Second Stage: Pre-operational Stage ($2$ to $7\text{ years}$)Third Stage: Concrete Operational Stage ($7$ to $11\text{ years}$)Fourth Stage: Formal Operational Stage ($11\text{ years}$ and beyond)Hence, the second stage is explicitly designated as the pre-operational stage.