One last comment about effective, varied reinforcement. Since the beginning, the Lovaas Institute's newsletter Meeting Point has featured 5 surprisingly different reinforcer ideas in each issue. I'd like to add my 5 favorite reinforcers to the list:

1. Put a child's hands on top of your hands. Count down slowly and with anticipation 5-4-3-2-1. Then yell "blast off!" and fling the child's hands into the air.
2. Pick up a child's foot and pound on the bottom of it with the side of your fist (with or without shoes on the child).
3. Blow air into the sleeves or back of a child's shirt.
4. Slowly lower a Kleenex in front of your face, then blow forcefully on it and let go so it zooms across toward the child.
5. Hasbro Playskool Busy Ball Popper Hands down one of the most entertaining ball toys.

Anyone else have a favorite reinforcer?