Dogs are always trying to figure out how any given thing fits within their space.
Whether its another dog, a human, a car, the corner trash can, a falling tree branch, or the paper blowing across the street. They’re always in the process of guessing “Is this thing (dog, human, etc.) safe or not?”
“Is this something that scares me?”
“Do I move away from it?”
“Do I allow it to get closer to me?”
Humans are not much different in this regard. Unfamiliar people and environments may invoke various emotions and responses within us. One exceptional difference is that dogs have trouble generalizing while humans can draw almost immediate distinctions between varying people and objects.
Dogs are always spatially aware and navigate life largely through visual processes. We humans, however, are much more auditory. Some dogs are hypersensitive to their surroundings, and their comfort and stress levels are often predicated on how familiar, or unfamiliar, their current environment is to them.
Many dogs have what can best be described as “proximity issue.” It’s as if they have a small bubble or circle around them and their current frame of mind will be dictated by who or what enters into that bubble or circle. Without knowledge of this specific problem an owner with a dog that experiences proximity issues can be in the dark about his dogs occasional aggressive tendencies.
You may think this is no big deal but knowing this deepens your understanding of how dogs think and why they react the way they do under certain circumstances. It also informs you in your efforts at dog training.