I agree with Liesje in that I don't so much think that using both punishments (sorry, I refuse to use the word correction) and reinforers leads to a generally confused dog, I do think what leads to a confused dog is not knowing what to expect, and how to make those reinforcers happen or how to avoid those punishers. I say that because the science works both ways, unfortunately. As long as the dog has a clear understanding as to what is expected, and what the consequences of different behaviours are, then the dog is not confused, per se.
I see the same level of confusion in a dog that is learning how to sit using either using a clicker for the first time, or using a choke chain for the first time. In the beginning, the level of confusion is the same. With a clicker, the dog doesn't know what it did to make the cookie happen. And with the choker, the dog doesn't know what it did to make the pressure from the chain happen. It takes a few repetitions for understanding to take effect. I think the same level of confusion is there, however I do think the stress levels will have very different outcomes, at least in the beginning.
I live with the philosophy that every dog needs to be treated as an individual, and learns in its own way with certain types of training better than others. I say that because I've trained a lot of dogs, and have learned easily that it's not a "one-size-fits-all" approach. What is good for one dog, may not at all be humane (or even effective) for another! The hardest dog by far I've had to teach is my current youngest, Shimmer, because you cannot use any real sort of punishment on her whatsoever.
Most know that I use very, very few intentional punishments with dogs, as I simply do not need to, nor does it fit into the type of relationship I wish to have with my animals. However, I don't deny when certain things I do are punishers. I can halt certain behaviours in Gaci with a simple "Hey" or "Eh".....and you can see clearly that you get a sort of "Oh, sorry momma, I forgotz my manners!!!". No harsh feelings or relationship strain is occurring there. And it's not in any way "affecting" the use of reinforcers or our bond. However, if I raise my voice at all to Shimmer, or even step into her space in a certain way, she will lay down and roll herself over in appeasement and become highly upset. I cannot use a raised voice to even stop behaviours, as it does impact her relationship with me, even if for a short period of time.
I have some very frustrating moments with Shimmer because she is very intrapersonal.....what I mean is she very much cares what "I" think of her, and she is very sensitive to my reaction in her behaviours. Not only with mild punishers....even in shaping if I cannot microshape her she will sometimes get upset at getting it "wrong", so I have to make shaping very easy for her, with a high level of reward, or find another way to get the behaviour (capturing, or luring). It was very hard for me to teach Shimmer some things, because I truly had to become almost "all-positive" with her....heck, even how I talk to other dogs influences her own reactions. However, through learning and experience she has made me an even better trainer, because I can take what I've learned with her and apply it to my other dogs.
Everything really does come down to "know thy dog, and what it needs in order to become the best it can be". I do think that every person should strive to start with no or as few punishers as possible, because most people will find that they can get what they want without it. But I also am not training a Schutzhund dog, so I don't begin to express that I know what is required and what is "wrong" or "right" when it comes to training those behaviours. I am not training a herding dog, so I don't begin to know anything about it or say "you don't need punishers!!!!!". But I know what I need for my dogs, and through experience in terms of pet dogs learning life skills, I could come up with an adequate and likely pretty accurate generalized list of what is or is not required to get those behaviours with minimal or no aversives such that if I were teaching a class, I would know how to help students get the best out of their dogs. We do have to keep in mind the perspectives, though, of those we talk with.
I don't mean to pick on Liesje, but she gives a good example of the differences between working with "pet dogs" and working with "performance dogs" (I hope that doesn't offend, but I do qualify Schutzhund as a sport rather than "working" as a real police dog) and I love reading her posts discussing the differences as well as how she brings it all together to make it work for her home. Working with performance dogs in another venue I do understand that sometimes things change in terms of how you get behaviour, and consequences for behaviour, especially when you are doing very technical or potentially dangerous work. But I love that she can then acknowledge that she does not use those same techniques on her "pet" dogs just because she can....because she doesn't need to, and because it could be detrimental.
Such as how Liesje explained that what she does with Nikon would be downright inhumane with her other dogs. That to me is a sign of a person with a true understanding of working with what the dog is, rather than what you want it to be. I say that because I experience it with my own dogs daily. They all get the same overall treatment, the same respect, and the same trust, but you sometimes get there through different means, and what's right for one dog may not be the best thing for another. That's what we all should strive to do, I think, rather than looking at any particular punisher or reinforcer and judging it on its own merit.