Public service announcement! :-)
Dominance has nothing to do with physical violence.
Scientists and dog/wolf experts do not deny that dominance exists.
The "debunking" of dominance has, itself, been thoroughly debunked.
An awful lot of people don't even know what this term means any more. It refers to the social hierarchy that all of Canis follows. However, some "positive reinforcement only" trainers are sick and tired of worrying that people might be rough with their dogs, in the (misguided) name of "dominance", so there is a modern movement to throw off the bad habit by denying that there is a social structure at all, including its leader (or "alpha") who has the right to make demands. This "boss", which dogs are naturally hardwired to accept, is a role perfect for the human owners--yet sadly too often filled by the dog itself, causing stress and problems for both.
Both social dominance/leadership AND positive reinforcement have their place, and when combined, make for a nicely balanced companion.
~This little girl shows lovely submissive behaviour towards her elders. She was readily accepted by the pack, and is responsive to human wishes as well.
Here are three additional links explaining what dominance actually is (and why it can cause problems) : Vet link 1 Vet link 2 SPCA link For further reading, you might try books by Roger Abrantes or other highly experienced ethologists. I also really like this comprehensive and detailed explanation.
"But I want lab studies!" Okay...I mean, they are less relevant than the work of ethologists, and the aggregation of real life experiences from vast numbers of handlers, and the direct application of the research by trying it yourself on your own dogs and reaping the benefits (!) but sure, have some formal studies. :-)
It might also be worth pointing out that there's no conflict between Zimen's and Schenkel's studies (unrelated packs) and Dr. Mech's notation of linear, biological families in his later works. Some folks developed the misconception that wolves in the wild attain their position by fighting, and that 'the currently most vicious or powerful wolf is the alpha'. In reality, wolves in the wild typically attain the position by virtue of being born first. (!) **The hierarchy exists** - but it is not typically won through violence. Young wolves respect their elders, and come pre-programmed to show deference. This is also true with captive wolves and wolfdogs, and often dogs, when you are introducing puppies. However, the Schenkel and Zimen studies threw together adult unrelated wolves (much as many humans do when adopting dogs), and there is when they saw a lot of dominance displays, posturing, and even fighting (when rank could not be determined by mere posturing). Overt dominance/submission displays are used to SET a new hierarchy, and afterwards, subtle displays maintain the pack order without fighting (which wolves can't afford; they need each other). Social dominance is alive and well, but the idea of "rule by force" was misunderstood, and short-lived. Dominance was never about violence, only leadership and priority access...and can be practiced by "force free" trainers to their great advantage.
p.s. The "alpha roll" is not forced by the alpha! It is volunteered by the subordinate. This is an important distinction, and a lack of understanding of how this mechanism works is likely to get you bitten, especially with a truly dominant dog.
Want even more links? Many trainers have devoted time and effort to explain this important and very relevant concept.