If your dog thinks that it is the pack leader, it may become fearful and attack other dogs to protect you and himself. Dominant dogs will often attack even when they still have the option of running away. Fearful dogs will only attack if they have no place to run. The most important concept to grasp if you want to understand how to stop dog aggression is that your dog must first look to you as the pack leader. There are some fantastic video sites now that show you exactly how to become the pack leader.