I dunno Chris... what you call "natural" is completely unnatural and counter-intuitive. What is "natural" is that our reticular activating system is pre-programmed for flight or fight response. One of the primary reasons it is difficult to tell someone to try "relax" harder... it's completely counter-intuitive to do so, particularly when under duress.
As for babies doing what they do intuitively is not because it is "natural", it's because they haven't yet been subjected to environmental conditioning.
There's a big difference between "natural" movement and "internal" movement. Picking my nose and scratching my butt might be completely natural...(or unnatural... depending on your perspective) but whether that is internal or external is quite another thing...
Which leads us to what exactly is the definition of "internal"? Until this is addressed and agreed upon, the rest of this discussion is moot.