I've recently had a few very interesting conversations with other dog owners about whether or not dogs need to be told when they are wrong. These people have worked with some other trainer, and that trainer holds firmly to the belief that dogs need to be told when they are wrong in order to know which behavior is the correct behavior. In the case of this trainer's methods they used prong or choke collar corrections to tell the dog they are "wrong", although I have seen the same logic from trainers who utilize electric shock or any other physical or mental intimidation or threat. The owners I was speaking to had never even considered the fact that you can train reliable behavior without using any corrections, simply because they were never told the truth.
Here's the deal. When we are training our dogs, we are always giving them some information. So, when the dog performs the desired behavior we reward that behavior. When the dog performs a behavior I didn't ask for, or when they don't comply with what I asked? Do I need to correct him to let him know that response was "incorrect"? When we look at this argument at face value it seems logical to say "yes, the dog needs to know correct and incorrect!" In fact, some trainers hold fast to the belief that not correcting is cruel because it makes the training more confusing for the dog.
BUT. WAIT. JUST. A. SECOND. Isn't withholding the treat in and of itself information? Allow me to anthropomorphize for a moment (I do love a good anthropomorphism!!!).
My Fiancé was recently offered a work bonus if he maintained perfect attendance through a certain period of time. If he took any time off during that time period, he didn't receive the bonus. Guess who didn't miss any work during that time? (Not to say that he usually does! He has stellar attendance regardless...) Now, if someone did miss during that time period, they simply didn't receive the bonus. They weren't docked their usual pay. They weren't kicked out. They DEFINITELY weren't shocked or jerked around like some suggest you should do with your dog.
When we train positively we are giving our dogs two consequences. They either get it right and get what they're working for (cookies, play, chasing after squirrels, etc), or they get it wrong and the reward is withheld. And the dog absolutely knows they tried the incorrect behavior, and they should try a different strategy.
So, long story short and what I always come back to: you never have to hurt or scare your dog to get correct responses. Enough positive reinforcement for the correct response, while your dog learns that other responses don't work, will create reliable behavior. It's science.
In conclusion, here is a video of my adorable fella politely walking next to me, without having ever had a correction applied. Good boy, Regis!