Piaget is one of the principle developmental psychologists who has investigated cognitive development over the long run. Vygotsky and others have looked at if from a narrower perspective. Do not forget to include them as appropriate.
Identify the range of ages associated with this stage.
What stage(s) of cognitive development does Piaget associate with this period of life?
What can the individual do now that he or she could not do before?
How do we know what the individual can do? (What, if any, special methodological procedures do we employ to find out?)
Be sure to use, and define or illustrate, the proper terms used by developmental psychologists.
I would expect this assignment to be less than a page in length. (A whole lot less is going on now.)
Provide proper references.