Jean-- Here ya go! "Click to Calm" by Emma Parsons. (Please PM me if you'd like me to mail you my copy-- truly!) This book was written by someone with a fear/aggressive/reactive dog. A real sweetheart of a Golden, but reactive. Guess what? She DID click when he was being horrible! BUT-- Here's what she did. She began by "charging the clicker" (click, treat... click, treat... click,treat. Until the dog associates the click with the goodie) Next, she waited until her dog saw another dog and flipped out. Anytime he took even a TINY break in his freak-out, she clicked and treated. Then, she began clicking and treating as the windows of calm during the "freak out storms" got gradually wider and wider. She claims this DOES happen. Anyway.. the entire book is about treating fear-reactivity in dogs using a clicker!
Guess who taught me clickertraining? A Schutzhund club president who I admire with all my heart! He uses corrections, but loves using clicker as a marker, especially in young dogs or teaching and shaping a new behavior.
To the OP-- It depends on the dog:
My last dog, I could have clicker trained using mostly positive methods, little correction-- because he was a very soft showline dog who had zero dominance agenda
My current dog is taught a NEW behavior using clicker, or voice as marker. I can use food reward very CAREFULLY
with this dog. He absolutely needs some corrections-- plus caution using food-- or else he becomes agitated, uppitty, pushy-pushy-pushy. Bottomline: Some dogs, loving though they are, are still born with "the warlord gene." Some dominant dogs can turn "purely positive" no-corrections methods around on you, so that you become their 2-legged mobile foodbowl, with them the boss and you the obedient goodie dispenser. (May even have to defend their mobile goodie dispenser against other dogs on walks, too)
You may well get the behaviors you want-- but the general attitude of the dog turns frantic-pushy-irritated-bossy.
My opinion: "Purely positive" may work for some dogs. You have to know your dog-- and be willing to accept it if your dog reacts badly to this no-corrections trendy training methodology. This is hard in a world where class after class is offered with Shelties, Cockers, and poodles dancing along to zero corrections and clicker/treating. Some dogs need the handler to give corrections sometimes, or else they feel antsy that the top spot in the pack needs to be filled. My dog r-e-l-a-x-e-s when he get some needed corrections.
He doesn't get many. My attitude is as important as him getting the corrections when he needs them. Why should he stress out? The top spot in the pack, apparently, is taken. He was maybe just checking.