J signs "MORE"

hi all,
A funny story. As an "expert" signer you would think I would be able to recognize when my 7 month old signs to me, but apparently not. thank goodness I have his sign "MORE" on videotape. It was only then, when I reviewed the videotape a few days later that I saw my son sign! I was throwing a ball in the air and he was laughing away, as the ball rolled away from me and I turned away to retrieve it my son sat up from his intial laying down position and slapped his hands together (one on top of the other). This exact scenario happened twice!! Of course I was looking for the ball when he signed, but..I should have spotted it and then praised him for it!

You really have to pay attention as obviously the infant is not going to alert your attention first before signing!
Anyone else have a similar experience?
Natasha