Ok, ok...the majority of the experiements, the experimenters, the long time professional trainers of police dogs in the experiments and other dogs, the behaviorists, the scientists are all wrong. Low level, mild discomfort is all it took to deter your dog. Great. I don't buy it and neither do they.
Wild canines, ancestors of our dogs and other animals take big risks to hunt food. They get hurt sometimes by antlers and strong kicks. Sometimes they get killed. They risk it because they need to eat. It's a VERY strong motivator to eat and survive. It's an instinct that hasn't disappeared from domestic dogs. They may not need to function that way to live in most cases, but those drives are still present, as we can see. They'll take that risk and significant pain and injury in order to take down game to eat and survive. Dogs can put up with a lot. They learn caution and how to maneuver around things, how to weigh the risks. I just don't want to be the one that they're cautious about or afraid of or aggressive toward.
Your description (in another thread) of your dogs playing very rough and getting ouchies by teeth or claws in a worse way than the shock collar happens and they get pinched in a door that slams on them by accident and they get porcupine quills in them...all those natural aversives. My dogs play rough too. Lyric has made bite wounds on Toker enough to bleed a little bit. He really gets rough. I've had to intervene lately because it's no good that she gets these ouchies. But for her preference, she goes right back for more play, it doesn't deter her for a second. She's a wild woman.
The rough play is a higher motivator than the wounds are a punisher. That rough playing never extinguishes. The door has slammed on a foot or body by accident and they are not afraid to go through the door again. Going out the door to play is a higher motivator than the pain or fear of the door slamming on their bodies. My Lab got into a porcupine three times in one summer. She never quit going after them. She was determined to get that thing no matter what. The pain of the quills and pain and fear she went through while getting them pulled out all over her body, inside her mouth, her ears, eye lids (not fun at all, as you know) was apparently not as powerful a deterrent as the motivation to get the porcupine was. In other words, the intensity of the motivator was higher than the intensity of those aversives. None of those painful things extinguished those behaviors in your dogs or in mine.
So, your low level shock or "tap" as you like to call it, to your dog is so mildly painful that it is enough to make her turn around from running off in a determined prey drive... to return to you? How is it that a low level, no pain or fear eliciting "stimulation" is enough to deter such powerful, intense, focused prey drive which you describe your dog as having? How on earth would a mild discomfort that does not elicit any significant pain or fear extinguish that behavior? If it is associated with you, and it wasn't too painful or frightening, I could almost understand it since dogs have a social thing going with us, but that would be due to her wanting to focus on you, wanting to please, in which case positive methods would work exeedingly well if they had been systematically done with "prey" exercises, which start small and work up. But you say the dog does not associate the shock with you. (also disagreed with by the studies and everything I've read from loads of applied behaviorists and science, brain chemistry has been tested, body language, small nuances perhaps that you don't notice but the scientists do)
Just one more thing: (Oh, and this isn't just for you Melanie....this post. It's for anyone considering using an e-collar) When the shock collar is put on an adult human, the human is expecting it, knows somewhat what to expect because we understand about electricity. That is not part of a dog's natural world and I would expect them to be much more confused, bewildered or frightened and stressed. They don't know what is happening to them. It is such a weird and foreign sensation, I would imagine. It's extremely unnatural to them....electric shock. Maybe it doesn't have to be highly or excrutiatingly painful physically. Maybe there is more emotional consequences. But some big, adverse event has to be happening physiologically and emotionally to get such a tough, highly driven dog to turn around and come to you when it is so extraordinarily motivated by something in the environment. And that is confirmed in the big picture, in the vast majority of cases. Most experts in animal behavior are horrified by the use of these electric devices. Animal welfare groups, big, well known kennel clubs etc (already mentioned in link who all) are against these devices and feel that it is "barbaric" to use such a thing on an animal. They're calling for bans all over the place. Vertinary scientists also have grouped together to oppose their use.
No one can really say they are all for positive reinforcement and then from the other side of their mouth say they are for shocking their dog.
Motivation and reward training methods, positive methods, clicker trainers....whatever one wants to call it is diametrically opposed to using that type of aversive. It goes against the principles of learning by way of positive reinforcement. It doesn't make sense to do one with one skill and another with another skill. The theory of learning behavior doesn't just work on certain tricks, like sit, down, stay but stops working on things like heel, come, or roll over. There are other ways, in other words. There's nothing wrong with having trouble with something, but there is something wrong with insisting on using a device like that which you feel is not good for other training skills but ok for the recall. I feel that it's taking a big risk. Glad it all turned out OK for you. But it most certainly screws up a lot of dogs, as is evident not only in a huge number individual cases I've read about, but also in controlled studies done by people in the know. And they're NOT ALL doing it "wrong."
There are exceptions to everything. Your dog may not have been damaged to the extent that some are. She may not show the outward signs that you can see which indicate a shut down dog. She may have come through it all right. But that doesn't mean that it's OK to use an electric shock collar on an animal. It really is a harsh thing.
That is all I can think of to say.