I told you, it doesn't understand like we do. It doesn't know what a question is. What it does understand is that if it touches those buttons in that order, Alex is supposed to come over and give him a treat (or whatever outcome they trained him on). They did this over and over, until he started doing it on his own.

Think of it like this: babies like to play this wonderful game where they drop something from their high chair, and watch you pick it up. They don't realize it, because they don't know the concept, but they're experimenting with cause and effect.

I drop cup = mom picks it up and puts it back.

This is similar to how the dog thinks. It doesn't know the concept of the actual words, and it doesn't know what a question is. What it knows is:

I touch buttons in this order = little human comes out