I got home from work and took the dogs out in the back yard. We played ball for about 15 minutes and then I went inside. Loredo had lagged behind so I just went in and closed the door. He realized he had been left out and came running up to the door and peered into the glass window. He spotted me walking to the pantry where their food is and he got all excited and without any warning or delay… he ran through the doggy door.
After dinner he watched the dogs go out of the doggy door (which they always do just after eating) and he ran to the glass door to be let out. I walked to the doggy door and held the flap open and he same over, sniffed, and then darted out.
He played with the other dogs till they all came in and he stood on the porch at the glass door peering in and then without hesitating, he ran in the doggy door. For the rest of the evening, when any dog went out the doggy door, he ran to the kitchen and darted out the doggy door to follow them.
That has to be about the fastest I have ever seen a dog learn what the doggy door is. He is fearless and is just a bundle of energy. So, once he figures something out, he just adopts it and has no problem repeating it over and over.