The article "The Hero's Journey: Are You Experienced?" uses the Dreyfus model of skill acquisition to explain how people learn: Initially, when they are novices, they cannot handle a lot of contradictions. They want to be told what to do and everything must be simple and consistent. Combine this with the observation that abstractions must be built by amassing concrete examples, and one can derive a few rules for teaching (some of them borrowed from "Hero's Journey"):