Mostly, problem barkers bark because they are bored. Accustomed to a lot of attention, they don't know how to behave when alone. More often than not, we have set this up ourselves. We want our dogs to be happy, so we spoil them: our dogs get treats and petting whenever they wish. It is entirely normal for owners to act this way and entirely normal for dogs to complain when they feel neglected.

First of all, your dog must learn that barking for your attention doesn't work. If your dog is unhappy outdoors and barking eventually makes you bring him in, he learns that barking gets results. If barking makes you yell at him, well, that's better than nothing. "I'm bored. Maybe I can get them to yell at me again." Although yelling doesn't work, negative reinforcement can still be useful.