Drawing IS the afterglow of a reaction of the senses. Small children do it naturally -without plan or pretension. Their seemingly meaningless scribbles reports raw kinetic energy -feral and quite alive. Then at some point children fall prey to the tyranny of appearances -that some how a good drawing mimics objects. Teachers might even facilitate this by giving little Mary a gold star for drawing a "perfect" apple that has been neatly colored in. Drawing becomes less naturally reactive and more analytical and contrived -like other aspects of human life.
Uninhibited gesture drawing -or scribbling- gets at the basic reality that everything is always doing something. In other words, the action of the object is the object -even if the object is sitting there quietly. Beyond being an art lesson it is a life lesson.