thoughts on this: As a kid I was naturally ambidextrous, but as I grew up chose my right hand as my dominant one. The past year or so I've been trying to re-learn how to write with my left and do other things simply out of personal interest.
What is to be noted here is the vast improvement with my non-dominant hand. I approached drawing the same way--why was I more successful with one hand than the other? As a creative writer it's sometimes suggested you brainstorm using your non-dominant hand because it unlocks parts of the brain not generally used. As we learn more about something our brain creates shortcuts when repeating a task in order to be more efficient. The leap in quality from one hand to the other is suggestive of huge mental blocks when drawing. When learning to draw student's are generally referred to as 'learning to see'. Which I think is also a large implication of the struggle a person naturally has to overcome when drawing.
The very fact that people have these mental blocks and have to remove themselves from seeing things only in symbolic representation (artist's often hear "you're drawing what you think it looks like, not what it is") is extremely interesting in itself. The very fact that this is even a struggle at all gives great inclination to the patterns of human nature. What mental blocks do I have when living my day to day life and not drawing? The fact that we can live so delusionally and simultaneously be so comfortably ignorant of this fact is sort of terrifying.