It’s nothing more than a theory (developed after my horror at my dog)s reaction to the very nice Indian bloke!

Racism as such depends on having preconceptions about races, and according values to them accordingly.Desensitization is starting with a very low-level intensity of aversive stimulus until the dog habituates to (or changes his association with) the aversive, and then gradually increasing the strength until the dog is comfortable with the stimulus at full intensity. The “black/white” (dark/light) skin color distinction is certainly a visual one; so the fact that dogs can pick up on that while they might leave other racial distinctions aside is fairly predictable. And cyclists (he's even been known to bark at a pedestrian who was walking to his bike, was impressed at that insight).

It took a very, very long time to persuade him out of it - he's now 15 and doesn't do it often, but that's the best I can say. My Dad is black and she gets on perfectly well with him, so it's not an anxiety or 'hatred', maybe she recognises the skin colour difference and thinks it's my Dad. It just means he lacks experience and needs a proper, positive introduction to more people who don't look like or dress like you. This is much easier when the dog is reactive to buses or skateboards; you’re really not going to hurt the bus driver’s feelings, or even the skating kids (I’ve always found them wonderfully helpful!What she didn’t know was that it was far from the first time I’ve heard people describe their dogs as such. More often than not it means they are fearful of, unsure of, have had negative experiences with, or haven’t been exposed to enough of the type of person they are concerned about. I'm very unconvinced by this - my dog had a real thing about people in hats and would bark wildly at them. so it doesn't seem crazy to me that if your dog isn't used to seeing people who look different it might react badly.

This “story” is a total of 18 pages of only 3 to 5 words per page, followed by 12 pages of advertisements. Relevant to your question, this guarding/protection applies not only to interlopers but also to characters who don’t fit in or appear importantly different from the rest of the dog’s pack. blocking with your body; getting in the dog’s visual field; backing him up; turning and walking the other way…these can all communicate to your dog that this behavior isn’t admissible.I always advise my clients to expect to take two steps forward, and sometimes one step back, but to keep working.