26/08/2026
In dog behaviour, we often talk about a dog being “over threshold”. Something that isn’t one fixed point and it doesn’t look the same for every dog.
Put simply, a dog reaches threshold when what they are experiencing is getting too much for their current capacity to cope, respond or learn.
But we need to know the emotions behind it and not just deem them over threshold because of their behaviour. I’ve used the emotional and arousal circumplex here because it helps us look at two different parts of a dog’s experience:
• Emotional Valence — whether the emotion feels pleasant or unpleasant
• Arousal — the level of activation or intensity within that emotion
Dogs experiencing unpleasant, high-arousal emotions such as fear, distress or frustration may be more likely to go over threshold (the red area top left). This might look like barking, lunging, pulling, frantic movement or being completely unable to interact with their owner or handler.
But high arousal isn’t automatically negative. A dog can be excited, playful and at high arousal while still having enough capacity to respond, make choices and learn the yellow to green area top right). Equally, a dog does not have to be highly aroused to be over threshold.
Low-arousal states can also reflect a dog who is no longer coping (bottom left red area). Withdrawal, stillness, showong to be shutdown can easily be mistaken for calmness—particularly when the dog is quiet, compliant or no longer reacting.
(*The colour grading is my interpretation to help illustrate the point)
This is why we need to understand not only what being over threshold looks like, but what it might feel like for the dog.
Behaviour is only the part we can see. Emotion, arousal and the dog’s remaining capacity help us understand what may be happening underneath it.
