Drawing Development in Children - A design educator's perspective

As I was researching for materials on teaching and learning about design, little did I realise this need to also consider the artistic development of my charges, as I move into looking at their overall level of designerly intelligence, or what I shall call their Design Quotient (DQ). It is interesting to note that there are indeed a few literature that deals with the topic on a child's artistic and sketching development, but there are even fewer...if any at all, that deals specifically with using their sketching ability to explain their designerly thoughts! One site that I saw reveals a very interesting yet easily understood table of sorts (learningdesign.com) on the drawing development of children, the screenshot as shown below.



What I am curious to know is how children develop their design thinking, and what better way to explain their understanding of the design process than through the medium of expression offered by sketching and drawing. Nothwithanding their rather limited ability to offer at least a basic degree of realism in their sketches, but what i am more concerned here is not so much of the realism of these ideas, as to the ability to put onto paper their thoughts and ideas...in as far as design is concerned.

I do remember sketching out a bulky design of a wrist-band-like contraption that will enable its user to 'shoot' short arrows tied to strings, using springs...after being inspired by watching the TV version of Spiderman, back when I was just a 7-year old Primary 1 student! Now what I am curious is what goes through the mind of similarly-aged children, or even older, when they pencil down their sketches. Was there any design enlightenment when they sketch out those sketches? Details...what about the details that they put in into their sketches? Does these reveal a lot more about these children, especially so about their ability to see things beyond just the obvious? Give me some time to dwell on this a little further, and I do hope to be able to offer a little bit more.