Extract from Aunty Kaye’s Doggy Dictionary of Training and Behaviour
A dog will try to avoid unpleasant or frightening experiences. Sometimes dogs will find training, especially training methods using force and correction, stressful and will therefore show avoidance behaviour. This may take the form of turning their head away, retreating, moving slowly or lying down. Dogs also avoid objects they find threatening. They might slink past garbage bins, strange people or other dogs, giving them a wide berth or hiding behind their owners’ legs. Some of these reactions are considered to be calming signals.
Avoiding something unpleasant can be just as rewarding as gaining something pleasant, so avoidance behaviour brings its own form of reinforcement. After experience of successfully avoiding the big boogy bin, your dog will be even more inclined to give it a wide berth, and will not have a chance to learn that it is really harmless.
This doesn’t mean you should force your dog to approach, but it does mean that it’s best not to make a quick getaway either. Take your time to approach little by little, chatting playfully to your dog, and using food treats to create a pleasant association.