Quote Originally Posted by kitana View Post
If it's so small that you can't feel it, it won't affect the behavior at all. If it affects (stop) the behavior, it is therefore strong enough to be felt, and if it strong enough to be felt, it can have deep effects on the mental of the animal.

The resources about the side-effects of punishment are widely available, more than that they are widely vulgarized for regular people without a degree in psychology. If you look up Jesus Rosales-Ruiz research on poisoning the cue, and continue from there, you will be on your way to get a better understanding of punishment and reinforcement. Plus, many of the articles on this website (http://www.clickersolutions.com/articles/index.htm), although not all of them are from post-graduate researchers such as Jesus R-R, are bringing excellent infos to ones who want to understand. And finally if you are really interested, grab Temple Grandin's book "Animals in translation", it will blow you away, but it is not an easy read. It goes in depth about fears, consequences of punishment and fear, etc, but is still understandable by the general public.
I might not have been clear about the way I worded a sentence. If the stimulation is so slight that I personally can't feel that level of stimulation with my fingers but the dog can feel it, I have a hard time believing thats going to do the dog damage....?