I rarely speak of Dahlia's reactivity in public and it's certainly not something I talk about with friends and family. Sometimes I still fight against the stigma, against the way that people view reactive dogs.
Yet she is none of those and nor has she ever been those. There are many reasons dogs are reactive, but the two major reasons are:
1. Fear. Dogs that lack socialization often react to every little noise, every little thing they see. That tall guy in the hat? They've never seen something like that before, they get scared, and so lash out. Barking and lunging will make the scary thing go away! That dog who is easily twice their size? They've never met a dog that big, they get scared, and lash out at that. To the laymen it looks like aggression and while it's a form of aggression, the root cause of it is fear.
2. Frustration. Some dogs have little frustration tolerance and so when they see something they want to get to but can't (because they're on leash or behind a fence), they lash out in frustration. I liken it to a toddler throwing a temper tantrum. They lose all control of themselves and bark and lunge. It looks nearly the same as the fear response, but isn't.
The body language for the two is different, especially in the ear set (back for fear, forward for frustration) and tail set (down much further for a fearful dog).
Dahlia came to me with frustration reactivity. I had never heard the term before and while I knew a lot about the basics of dog training, I realized I better get off my butt and do a more thorough study. I read a lot. I spoke with a lot of trainers and behaviorists. I watched DVDs and read books on body language. I started to go out and study dogs and their owners and talking to people to figure out why their dogs were acting the way they were. What caused the reactivity?
Then I set to helping my dog. I figured out her triggers (other dogs) and how close those triggers could get before she started to react. I figured out the little body language signs that meant a reaction was imminent. And so I started the "Look at that" game. "Look at that!" I would proclaim when we saw a dog just at the right distance away (close enough to be noticed, but not close enough to elicit and over the top reaction). Dahlia, of course, was looking already. And then she'd turn to look at me because of my excited voice. At that point, she'd get a treat. Something really delicious.
We did this every single day for months. Little by little we were able to get closer and closer to the other dogs. Finally she could walk by a dog who was on the other side of the road without reacting about 90% of the time! So then we moved it closer, first stepping into the grass on the near side of the sidewalk then just off the sidewalk, always creeping closer and closer but always playing the "Look at that" game.
It took about a year to get to the point that we're at now. Dahlia is almost completely non-reactive. She has the occasional episode, especially if we're just leaving the house after she's been alone for a few hours, and we come across a dog who is too close and whose owner is jogging with him (the desire to chase is strong!). But those happen so rarely that I would call her about 99% non-reactive.
The journey to that was long and a constant up and down struggle. We'd make good progress, then something would happen that would set us back a bit. She bounced back quicker and quicker each time, but it still was not a steady upward pace. I've seen this same unsteady progress from other dogs I've helped out and I've read about it from many friends who have dealt with reactivity too.
Recently, I've been reading some stuff from folks who are harassing a friend of mine. They gave her a dog who had been locked in a room for most of his young life and has a lot of fear and a lot of reactivity. A lot more than my dog ever did. It's been only a few weeks and they are expecting a miraculous recovery. They're expecting this fear aggressive dog to be fine in the house with the person's other two dogs. They're expecting her to film him outside while training. They're expecting daily updates (which anyone with a reactive dog knows is pretty ridiculous due to the aforementioned ups and downs of working with reactivity). It sure would be nice for this dog to learn to live in the human world, but when a dog lacks early socialization, it's hard and it takes a lot of time.
If you have a reactive dog, take heart! You can work through it, but it will take time and dedication. It's all worth it though, isn't it? The moments when a dog finally walks past another dog, notices him, and then look at you instead? They make it all worth it.