In a TED talk about visual hallucinations, Oliver Sacks says there's a specific area of the brain which is activated when one recognizes, draws, or hallucinates cartoons. (13:53)
So I looked for whether Scott McCloud had anything to say on the subject, and found this.
Unfortunately, the link to the Korean study doesn't work, but there's a more detailed discussion of identification with cartoon drawings than realistic drawings here.
I don't know if the existence of cartoon section of the brain has any implications for drawing. At least, I would hope that my well-read friendslist might know of a cartoon or so on the subject.
Where poking around McCloud's blog, I was reminded of the Zoomquilt, which is still a lot of fun.
TED link thanks to shadesong.