"The first scribbles of a very young child of three or four...are joyous emotional and physical outlets with no conscious strings...uninhibited, in contrast to the lack of adventurousness in the grown-up which causes him to follow a 'style' to its usually dead end[.]"
"[I]n addition to the free scribble process, he should be gently led to involve the conscious world of his daily life with this instinctive art flow."
Zaidenberg suggests playing a game with your preschool-age artist. When your child draws what appears to the adult-eye as a scribble, ask your child to help you find the shape of an object or a person or an animal. You can rotate the paper to do this. You can say, I see an elephant's face with a long trunk. It's the opposite of what an abstract artist does; an abstract artist starts with an elephant and "takes from that object the elements of shape and design which he considers important..."
Lastly, Zaidenberg says to ask your child how he FELT when he made the scribble. Does the scribble mean happiness or anger? Does the scribble tell a story?
Doing these things help a child make the connection that they can communicate their imagination and their feelings through art.
(quotes are from pages 64-65 of YCIAA by Zaidenberg)