A trigger is anything that is actually present in the environment or in a memory of the environment that initiates a physical response or a reaction.

You will be all too familiar with your dog's primary triggers. These are what your dog reacts to - the other dog, the stranger, the fast-moving vehicle.

Of course, it is not always as simple as that. Your dog might not react to all dogs but may be selective according to color, breed, size, how busy they are or how close they are.

And there are other less obvious things that can be secondary triggers for your dog. These are things that make your dog more likely to react. There are lots of these but things to think about include location, weather, how you are feeling, who you are walking with, what your dog has done recently and how well your dog feels.

Triggers are cumulative so it is the combination of these factors which create the specific context that will determine whether or not your dog will react. We call this trigger stacking, and it can make your dog's behavior feel unpredictable. Sometimes they will react to a dog, another time they won't, so how do you know?

You need to know what factors are primary or secondary triggers for your dog. Keeping a diary can help with this. If your dog reacts, note down everything you can about the situation. Where? How far away? What kind of dog? Time of day? Weather? Anything unusual happening?

The more you can learn about your dog's responses the easier you will be able to predict what they will react to and therefore keep them in the Green Zone.