From my TTouch notes:
Aggression comes from a place of fear, and is a cry for help!
Behaviors that can be interpreted as aggression - growling, snapping, biting, lunging, reactivity, barking, etc - stem from a dog feeling that it needs to defend itself. A dog that feels it must defend itself feels threatened and afraid in some way. Thus, aggressive behaviors stem from a place of fear.
Yes, dog trainers may try to argue with me here, saying there are different types of aggression and that aggression can be learned. I do agree with those statements, but if we look at some different types of aggressive behavior, they do indeed stem from fear.
A mother protecting her puppies feels that someone or something is threatening them and maybe her. Threat = feeling of fear that something bad will happen to her or her pups. She feels defensive - that she needs to chase this thing away.
A dog snapping at someone when it is eating a meal or a special bone, or guarding its favorite toy or sleeping space is afraid that it will lose whatever it is that is important to it at that moment. This is where the behavior can also be learned. It starts from a place of fear and feeling threatened that it will lose a resource that is important to it. If the aggressive behavior works and the dog gets to keep that resource, the dog learns how to prevent the resource from being taken away. But still, the behavior begins from a place of fear.
Dogs that snap or bite when they are touched or reached for are not trying to be dominant. They are afraid to be touched for some reason ... maybe because they hurt when touched, maybe because something they don't like happens to them when they are touched, ... there are many reasons. But it stems from fear.
Reactivity comes from a place of fear and the dog feeling that it needs to chase away the feared person, animal or object, before it can pose a greater threat.
When you feel afraid, your ability to think is decreased. You start to move over to reactive mode. The same is true of our dogs. If you are afraid and someone you trust offers you some help to get out of the situation or to feel better about it, this is appreciated. If you get no help and you have to rely on yourself to get out of the situation, there are many ways you can react. You can run away from the threat or you can stay and fight it off. Often we don't allow our dogs the option of leaving or running away. Their only option is to fight back and try to chase away the threat.
When you see your dog react with behaviors that can be considered aggressive, stop and think about this statement - aggression comes from a place of fear, and is a cry for help.
Help your dog out of the fearful situation. Then review the situation in your mind. What was it that your dog felt was threatening? Sometimes this is more than one thing. When did you first notice your dog feeling uncomfortable and anxious about the situation? This is when you should have stepped in to help her. By stepping in earlier when you first notice your dog feeling anxious and unsure, you can prevent her from feeling that she needs to protect herself. Teach your dog that it's ok for her to leave a situation that she feels threatened by. If she is on a leash, this means that you must be paying attention to her at all times, so you can leave with her when she first begins to get upset.
No one likes to feel afraid. By changing your perspective about why your dog displays aggressive behaviors, you can be in a better position to help her. By helping her to feel safer in those situations, you will see her behavior begin to change as her fear goes away.