Children only draw full bodies. They may not always include a torso but they will always include limbs representing the body. Children can not conceptualize the bodies different parts thus they can not draw them separately. It is only in bad movies where you will see a floating head without the body attached.
Just a tip to keep in mind next time you are in the art department office trying to finish kid’s drawings for Set Dec. If you have the opportunity or connections with primary school teachers, it’s actually best to get children’s artwork done by children as adults have a very hard time trying to draw and think like children. We are far too co-ordinated.
I found a great article about the psychology of the way children draw. It’s really worth a read: http://www.answers.com/topic/children-s-drawings-of-human-figures
Have you ever noticed any films where the children’s artwork was so obviously faked?