If a fearful dog is found to be aggressive, the dog must be handled with a slip or martingale control collar. These collars are made to clip around the dog’s neck, fit tightly and allow the trainer to close the dog’s airways to end aggression. This is done in a calm manner, not as aggression prevention – which is discussed later – but as a safe and effective training method. http://www.leerburg.com/746.htm

Non-aversive immersion is commonly called desensitization. Non aversive immersion occurs in an area in which the dog is exposed to the a stimulus or object, but is not exhibiting a fear reaction. This area is represented in green in figure 1. In non-aversive flooding, food play and praise are used in classical conditioning to teach the dog that the stimulus or object equals good things. As the fear threshold recedes – and the non-aversive immersion area – represented in green in figure 1 – moves closer to the fear-inducing stimulus or object, the dog becomes desnsitized to the stimulus or object. As this progresses, the aversive immersion area – represented in orange in figure 1 – gradually shrinks and becomes nonexistent. At this point, the dog may interact with the stimulus or object and will regard it as a normal and ordinary part of its surroundings.


A dog, Sugar, is fearful of storm and sewer drains. The trainer’s first step is to determine physically where Sugar’s fear threshold is. The trainer finds that the fear threshold lies 4 feet away from a storm drain. The trainer walks Sugar to the fear threshold, and reviews sit and watch commands, as the dog is comfortable in this place, the fear threshold recedes, or moves closer to the storm drain. Then the trainer steps to the new threshold and reviews the same commands. The trainer repeats this 4 times until Sugar is sitting directy on the storm drain. The trainer then rewards Sugar with a larger reward and more enthusiastic praise than was given for the obedience commands and releases Sugar into play or a brisk walk in circles.


This is the faster and most fair way to alleviate fear of a specific stimulus or object, however, it is very easy for trainers who are not experienced in reading a dog to cross the fear threshold. At the instant the fear threshold is crossed, the trainer has begun aversive immersion.


It is absolutely imperative that a trainer understand that he cannot allow the dog to cross back to the nonaversive side of the fear threshold until the dog is no longer displaying a fear reaction. If the trainer allows the dog to back away from the fear-inducing stimulus or object while the dog is displaying a fear reaction, it reinforces the fear reaction and makes training confusing, unpredictable an ineffective.


In the even that the handler crosses the fear threshold, represented as a red line in figure1, the dog will begin to show a fear reaction - which may include signs of hypervigilance, dramatically increased anxiety, passive or active resistance, vomitting, urination or defecation, releasing of anal glands. Aversive immersion, also called flooding, is a technique that directly exposes the dog to a fear-inducing stimulus or object. It is absolutely imperative that correction or active igoring be used in aversive immersion to prevent reinforcing the dog’s fear reaction which is based on the thoughts a) it's ok to run away and b) running away makes the "monsters" go away. The appropriate correction for a passive reaction is a series of prompts or pops on the leash. The appropriate correction for an active reaction is using the leash to firmly restrain the dog from bolting or backing away from the stimulus or object. Actively ignoring the dog works fr some dogs, but the trainer must have time and patience to stand still in that place until the dog’s frear reaction ends – sometimes a matter of hours. When the dog steps closer to the stimulus or object, it should be restrained from backing away. In this way, the dog is approaching the stimulus or object at its own pace, but in a controlled and safe manner.


A dog, Bree is fearful of storm drains. The trainer briskly leads Bree onto a storm drain and firmly restrains Bree until she relaxes. The trainer then gives Bree a sizable food reward and calls Bree off of the storm drain. The trainer then repeats this sequence until Bree does not hesitate to step onto the storm drain.
As you can see from this photo, aversive immersion is considerably stressful for a the dog. For this reason, aversive immersion should nt be the first training option chosen.