The stockdog world is full of opinions and people who like to express them. I have watched 5 dogs and 7 people work a group of five sheep (I'm exaggerating, of course...maybe). This rarely goes well because everyone wants to take control, but no one is on the same program and there is pressure from too many places. When there is pressure from too many places, the sheep have no place to go and leaves them only one option, panic.
Livestock can only respond to one source of pressure at a time. If a group of handlers and dogs are working livestock, the ones on pressure need to hold pressure. Pressure should only added from one source at a time. If pressures are applied from one place at a time harmony and balance can be achieved. When multiple sources of pressure are applied at once you increase the likelihood of a fight or flight reaction.
This principle also applies to training dogs. Consistency will out train a method. When worked with consistency, the dog can learn what is expected and learn to respond, even if it is not the best method. If the dog is trained with constantly changing methods the dog does not know where the pressure will come from and will work in a constant state of reaction. It will be in a fight or flight state. When this is happening the dog is avoiding pressure rather than learning to respond and process what is happening.
Learning happens when the dog is in a responsive state. This is not to say new approaches should not be tried, since progress comes with experimentation. When learning and experimenting with new approaches and principles, be careful that you are consistent in your method. Be sure you are consistent with consequences, good consequences for good actions/choices and bad for bad (more on managing consequences another time). Make sure your dog understands where and when pressures will come so they know how to respond. This allows the dog to be able to focus on learning the new approach or principle being taught. Finding this balance is not an easy thing but it pays off in the end for both handler and dog.
When working livestock or dogs, you have the choice to force or help them. If you help them respond to pressures, you can educate them to new experiences, approaches or methods. Our job when working livestock, or dogs, is to make them believe; what we are asking is what they want to do.