How can I get my dog to like smaller dogs?

My 80lb black lab snaps and growls at all dogs smaller than him. He is very well trained and well behaved in everything else. He is also very friendly with people, cats, kids, and any dogs not smaller than him. Several people in my apartment building have small dogs, so passing them in the hallway is becoming a problem. How can I get him to behave around small dogs?

Try getting him to focus on very special treats (cheese, peanut butter, crackers) when he passes a small dog. Try it from a distance at first and if he behaves slowly move closer. It would be best to contact a trainer if this doesn't work.

Its a learned behavior, reward him when he is acting nice around other smaller dogs, so its not that much of a bully dog, He might of been attacked by smaller animal before to instill this aggression towards them.