Do most dogs treat people based on their physical apparence?

Hmm, I'd be dubious as to whether they judge based on appearance. It depends how you mean it. However, I will agree that like many animals, dogs will react in different ways based on body language. Just like if you show signs of fear or run away from a predator, you're probably a dead man, yet many people have avoided a potential encounter with grizzlies or big cats by showing some backbone.