As a person grows, his animal soul and evil inclination grow with him.
A child has a limited understanding of the world, and correspondingly his evil inclination is also limited.
A three-year-old wants construction paper.
Then, as an adult whose understanding of the world has broadened, he desires banknotes.
However, although the object of his desire has changed, the nature of his relationship to objects, of how his animal soul is controlled by and drawn after his drives, has not changed.
–Rabbi Adin Steinsaltz