A dog’s defence threshold is the point at which he responds to a perceived threat.  A dog with a low defence threshold will be what we call ‘spooky’.  He will jump at sudden noises and be inclined to startle and snap at anything unfamiliar in his environment.  (This dog, incidentally, although regarded by humans as having a ‘poor’ temperament, is the one best adapted for survival in the wild.  It is the brave, steady temperament which is the artificial one!)

A dog with a high defence threshold, on the other hand, will take most things in his stride and be fairly non-reactive.  It will take quite a strong threat to push him into fight-or-flight mode.
A dog whose avoidance threshold is very close to his defence threshold will tend to run as his first option.  A dog whose avoidance threshold is much higher than his defence threshold will tend to fight until the threat becomes too severe, and will then turn and run.
Try to match the three graphs below to the three descriptions of dogs which follow:
1. Excellent pet
2. Dangerous fear-biter
3. Excellent protection dog

The correct answers are: A-2, B-3 and C-1.  How did you do?

Graph A depicts a highly dangerous fear-biter.  This dog has a low defence threshold, i.e. he spooks easily and is very reactive.  However, he also has a high avoidance threshold, which means that his preferred behaviour when under threat is to fight, and the threat will have to become pretty severe before he backs off.

Graph B depicts the temperament we are looking for in a good protection dog.  His defence threshold is moderate to high, i.e he doesn’t spook at everything, but his avoidance threshold is very high, i.e. when he does perceive himself as under threat, he fights, and will continue to fight under considerable threat.  (This gap between defence threshold and avoidance threshold is what protection trainers sometimes refer to as defence drive.)

Graph C depicts a good pet temperament.  This dog has an extremely high defence threshold, probably too high for a protection dog, i.e. the dog is pretty much unflappable.  His avoidance threshold is very close to his defence threshold, i.e. when he does get spooked, the chances are he will run rather than bite.  A good Labrador will have a temperament looking something like this.