On a throwaway account here. I'm currently teaching myself to draw using that book and I think the author is really onto something.

My first experience with psilocybin is also something that led me down a similar line of thinking. When the drug really hit me and I looked at anything visually appealing (a painting or a movie) all I could think was, "So this is how a kid sees the world!" A tree (I still knew it was a tree deep down) just looked different. I saw all the little parts that made up a tree. There was no longer a filter to intervene and say, "Yeah that's a tree. You've seen a million." It was like my brain did a revert to its state years ago and it was amazing.