Melissa, 6, always has a sunny smile when she squeezes the hand of a stuffed toy and it says, "I love you. I'm your friend."
Her brother, Nathaniel, 8, stops and listens when he hears music on the television, with cartoon characters dancing. Then he'll pick up a rubber band and wave it around, like a flag at a parade.
These children are diagnosed with autism. The dictionary defines it as self-absorption and withdrawal into fantasy.
Their foster mother has a gentler explanation. "They're in their own little world. And you do your best to draw them out."