Asynchronous Development to me is more a case of not knowing which "age" child (physical agge is 8 1/2) I'm going to be interacting with at times. Is it the child that just finished reading an advanced article on global warming and wants to discuss alternative to whatever creates greenhouse gasses? Is it the child that cannot sit still through dinner because there is a really cool meteor shower starting soon and he "needs" to be ready? Is it the child that can only talk about the evolution of pokemon and which one he wants to catch next? Is it the child that is throwing himself on the floor in a temper tantrum because he tore the picture he was drawing?
Each of these aspects of my son require a very different interaction from me. Even more intersting is that in the course of a conversation or activity these aspects can overlap and comingle.