Do all children progress through Piaget's stages at the same rate?

No. While the sequence is generally consistent, children progress at different speeds. Some skip early stages slightly, while others benefit from extra time. This individual variation partly explains mental age differences.

Does Piaget's framework apply to adults?

Piaget focused on childhood development (birth to adolescence). Adult cognitive development involves different processes—wisdom, expertise, and emotional sophistication—which his stages don't fully capture.