Dogs as we know them today didn't exist in nature. We’ve selectively bred them thousands of years to achieve very specific physical and behavioral traits. One of the primary goals of this selective breeding was to develop an innate need for human guidance, and affection. In a sense, it has led to a sort of developmental incompleteness. Dogs are highly intelligent and take direction beautifully when properly trained. However, much like children, they possess neither the mental/emotional fortitude nor the capacity to problem solve to an adequate degree to inhibit their initial reactions to negative stimuli. Thus, they are unaware that they have an issue, and are unequipped to work through them without our help.
So, how does this tie into Aggression in domestic dogs? Well, when a dog is just a dog (meaning on its own with no home or owners) it has no reason to subject itself to the self-inflicted pressure of deciding what to do, when in the presence of another dog, or human. Now there are many dogs, like people, that are generally happy-go-lucky, yet desire attention and affection. There are also dogs who've conditioned themselves to fear other dogs, or humans as a means of protecting themselves. For example, if a fearful dog is approached, it must make a split second decision to run away, or to attack in hopes of scaring away, damaging, or killing. All of these behaviors bring about the same net result: elimination of the threat, thus the relief of fear of being attacked itself. Instinctively, a dog is smart to think this way. We as humans understand on a much deeper level that to exist under this constant stress is unhealthy. However, considering a dog's inability to work out complex thought processes to this degree, we must admit that staying safe by avoiding what it fears is far from ridiculous. Nevertheless, the unique trait of a dog is its ability to override its protective instinct when led by a handler who has developed a trusting bond with the dog. A dog that has conditioned itself over the years to react to humans out of fear can be counter conditioned and properly socialized, then successfully integrated into a human household where it’ll thrive.
The first step on the road to rehab is putting a stop to the dog's destructive habits. If the conditioned response to a human is fear-based aggression, then the dog should no longer be allowed to give any attention to humans for the time being. Instead, it’s taught to focus only on its handler, who introduces both structure and boundaries on leash. Walking under high amounts of structure is done to hold the dog's attention. If the dog sees someone and begins to display its preconditioned negative/reactive behaviors, then the handler cuts all attempts to focus on that person, and demands the dog's attention again, forbidding the dog to react in its ordinary fashion. When the dog’s unable to make use of the coping habit it has developed, or its outlet to expend the nervous energy it’s built in the form of aggression, then it’s exposed as fearful. When attacking is no longer an option, the dog tries to run, to avoid, or to bite the leash, or the handler in an attempt to free itself.
All of these behaviors are considered aggressive to most owners, and sadly, many trainers too. If the handler is experienced, with his/her leash work, as well as dog-attention control, then they’ll be able to effectively thwart all attempts of the dog's cyclical behaviors. As the dog fruitlessly tries to go through its usual options one at a time: pulling, lunging, barking, jumping, leash biting etc., it’ll eventually become discouraged as it loses confidence in its aggressive front. In the end, the behavior that used to create a desired outcome, no longer seems to be effective. Typically at this point, the dog begins to whine and shiver with its tail tucked, since it feels powerless and vulnerable. This is with good reason, since its survival strategy no longer seems to be effective. So why subject a dog to this? All trainers that I've met that work with aggressive dogs have been approached with this question. The short answer is that it’s healthier for the dog to let go of its need to feel aggressive, than to allow the dog to continue this behavior for the remainder of its life. In short, rehab is helping a dog work through its fears that induce those negative reactive spirals. For the physical and emotional safety of the dog, this should always be done by experienced handlers who know how to guide dogs into healthier coping habits.
However, simply subjecting a dog to this stimuli (that which causes the dog to react due to fear such as: dogs, humans, bicycles, etc) has worked, but it’s not effective enough for really fearful, or powerful dogs. This leaves all dogs vulnerable to attacking each other, and should therefore not be seen as a viable training method. Neither is rudimentary counter conditioning where the dog’s corrected firmly for reacting, but then given no further instruction to guide it.
Guidance is the key to rehabilitation!
A well-timed correction is always meant to do one thing: regain the dog's attention. This is done to stop any attempt to run, attack, avoid etc., in order to bring the dog back to a neutral headspace where its attention is on its handler. Corrections are attention grabbers! Once the handler has the dog's attention, it's still the handler's job to give the dog direction. If a fearful dog who knows how to walk properly on a leash and prong sees another dog and runs after it, then as it hits the end of its leash, it'll feel the jerk of the prong as the dog's momentum comes to a sudden halt. If the handler can time this correctly, then the dog will receive a perfectly timed correction, and it’ll refocus on the handler. While effective, this only a piece of the redirective process and far from a finished product. Prong collars and e-collars don't train dogs on their own. Once the dog's reactive cycle is broken, in that instant, it's up to the handler to guide the dog back into its "heel" position, or ask it to "sit" and "stay". The correction, or enforcement of a boundary serves only to inform what behavior we don't want to see. That input should then be followed with what we do want to see instead. In that moment, the dog was overwhelmed by fear. We gave it direction, and thus were able to control the outcome. What this means for the dog is that it's no longer its job to keep itself safe and happy, it's its trainer’s job and eventually its owner’s. Removing uncertainty and fear from the equation in turn removes the need for aggression. A reactive dog will not react for fear of correction. A properly trained, counter conditioned, and socialized dog will not react because the absence of fear will give it no reason to do so.