This is interesting just based off of the work I have done with dogs. Staring is predatory and reflects dominance this is actually a trait found in wolves as well as many species. Dogs do this as well as an intimidation tactic it is often seen in dominant breeds to test their human to see if they are able to get away with bad behavior. This isn’t always the reason they stare sometimes they just have a lot of focus on the activity you are doing. Dogs are more docile and don’t always view eye contact as a threat and do find comfort in their humans. I just think the underlying trait was passed on.