Yesterday I was watching my seven year-old play basketball. In that game, there were some kids who were already exhibiting some sense of naturalness with dribbling the ball. No prodigies mind you, but a sense of being able to walk/run and dribble without undue conscious focus on the ball. Other kids really labor with dribbling, much like you or I would be trying to balance several full cups of hot coffee at once. Most, honestly, can't even manage that. They can't remember that the ball needs to bounce and just start running around with the ball in their hands.
Dribbling is a lesson in proprioception, an unconscious understanding of the body in time and space. Proprioception allows you to bring the fork to your mouth without having to watch it all the way. If you've ever had children, you know that this is a learned behavior! Proprioception can extend to a ball or a bat in a sport. It can extend to your automobile. Witness the difference between driving your car and what happens when you rent a big u-Haul.
It is, admittedly, more of a leap to extend proprioception to writing. Let's move slowly. If you are a touch typist, that is propriceptive, much like the fork to the mouth. Handwriting also. But what about rhetorically? We have the idea of writing/rhetoric occuring through space/time. Obviously it does. We discuss topoi and kairos. So what would it mean to suggest that writing is proprioceptive like driving a car or dribbling a basketball? The intersection of body and technology in the unconscious navigation of space-time. Clearly space-time of a text (multimodal or otherwise) is abstract, but does that matter? Neuroscience demonstrates that we use the same parts of our mind to navigate a virtual space (e.g. a video game) as we do to navigate a physical space. That's not surprising. What would be surprising iis if we had a separate part of our brain for navigating virtual spaces! Clearly there's no time for such a thing to evolve, even if there was a need. The same thing is true for writing. 5,000 years of writing, in evolutionary terms, isn't much different from a decade of virtual reality. Certainly, writing involves the use of visual processing and the use of the body to write, turn pages, click on links, etc.
So here's the thing about expert writers (or so I would hypothesize). Expert writers, like expert drivers or basketball players, use different parts of their mind to write than non-expert writers. Inexpert writers, like many of our students, are hyper-conscious of their writing, laboring over each sentence–an effect that is made worse by the constant reminders about the importance of "correctness." So on one level, the goal of writing instruction is to help students develop a level of "naturalness" in writing. Nature is in scare quotes here as there isn't anything necessarily natural about writing (or driving or bouncing a ball for that matter). At another level, we seek to de-naturalize writing through reflection, cultural critique, heuristics, and the like. Because, in the end, the analogy to dribbling breaks down, and we must see writing as a far more varied and complex set of practices.
Curiously, media networks help us learn these lessons. I say curiously because we typically think of the online world as drawing us away from the physical. But this is really just an extension of a false opposition between the virtual and the real (for another day). Media networks de-naturalize writing by presenting us with varied conditions for writing. In some respects I think it is easier for us to recognize our embodied responses to non-written media–tapping our feet to music, crying at a movie, etc. Of course we are similarly moved by texts, but there's a clear affective difference in processing the heavily symbolic quality of letters and words.
Juxtaposing these conditions can help us develop some awareness of the proprioceptive navigation of different media. In the end, becoming a better writer isn't so much about being a better conscious composer of sentences or paragraphs. It's about learning to feel your way through a rhetorical space. It's about developing good instincts and learning to trust them. The expert baller not only dribbles the ball unconsciously s/he can see the flow of the game unfold before hir, twists and turns hir body without thinking. The expert musician feels the music. Writing is also about getting into the flow, while also recognizing that the flow is not natural but a complex combination of cognition, body, technology, culture, rhetorical situation, and so on.