Brain damage?

Sometimes, it seems as if children hear you speaking without actually hearing anything you say. A case in point happened this afternoon when I took Riley and Elizabeth to a baseball game and scored tickets for The Jackson Sun's skybox. Before the game, we had a long talk about how they were supposed to behave. No bickering. No asking me for money (which I didn't have) for $5 cokes. No hitting their grandfather for money.
"Do you think you can do that?" we asked them. With angelic expressions, they answered, "yes."
Fast forward to the game, and it seems like they didn't hear anything we said. They started bickering the moment we got in the car to go, and didn't stop the entire game. Elizabeth started complaining she was hungry in the first inning and didn't stop until her grandfather broke down and got her food. It was like they didn't hear ANYTHING.
I'm reminded of the old Bill Cosby routine about brain damage and kids. I used to just think it was a funny bit. Now, I realize just how insightful Cosby was. And I think he was right on the money.