If you want to know what rule a child is using to build a structure or guide the actions of a character in a story, try this strategy. Ask a child if she will allow an alternative version of the structure or action. We call this strategy using the “not” as in, Y is not X. In the following video clip, the teacher suggests that two-year-old Ayla place her toy horse in a different location. He asks Ayla if he can place the horse in a new place. She says, “No” but does not give a reason why the horse has to be where she placed it. The teacher is trying to find out if Ayla can give a reason that goes beyond, “that’s just where I placed it.” So he asks again, “So, you don’t want me to put it over here?” as he moves the toy horse. This time Ayla gives the teacher a reason why the horse needs to be where she places it.