Little explorers

I think kids explore with their taste buds. I'm not talking about the way Ali will drop his "ba" (pacifier) on the ground and then just pop it back in. No, this is the thing that kids do when they go to someone else's house, usually for the first time. Tonight we met my mom for dinner at the cafeteria where she is staying. We all ate. Then we went to visit some friends. They'd gotten toys for the kids, but after a while, Ali decided he was thirsty- so I told him to ask for some water. He did. A little later, Leila must have told our hostess she was hungry, because she soon sat down with a yogurt. Of course, Ali had to have one, too. After that, a bag of animal crackers came out that they shared. We then took my mom back to her dorm room, and Leila discovered the goodie basket on the counter. Soon she was munching away on a cereal bar (which I made her share with Ali.) Back in the car on the way home, Ali tells me he's hungry.
Since it is biologically impossible that the kids are really that hungry, I think they just wanted to explore the food that was available at someone else's house. I've noticed this before with kids that come to our house for a visit. They won't be here long before they announce- I'm hungry. Some of them are happy with the first snack, but others keep looking for more food. Even if their mothers complain that they won't eat at home, the kids want to eat here. There's something about food in someone else's house.
What do you think it is?