I think the little girl and people like her have no concept that she should be cautious of the dogs so she walks in just like it's one of the dogs she's been raised around and it calms the dog. I think it scares a dog when someone is nervous around him.
I agree. A calm confident person gets a calm dog. A person trying to project confidence when its not there gets an aggressive dog. And as u said nervousness gets nervousness. I also know the emotional state of the person the dog is closest connected to will affect the emotional state of the dog.