People move through three stages of cognitive development in the way the mind is used to translate experiences into a model of the world (Bruner, "Toward a Theory of Instruction" 44-45).
Enactive: During earliest childhood, learning occurs through movement or action (as when babies learn to walk or a child learns to ride a bike).
Iconic: During middle childhood, learning occurs through images or icons that represent or summarize objects or events (as when children draw pictures of their families or a summer vacation).
Symbolic: During adolescence, learning occurs through abstract symbols (as when students are able to represent mathematical functions using equations or understand metaphorical language such as “Too many cooks spoil the broth”).