You will hear trainers talk constantly about a dog being under or over threshold. It is one of the most useful concepts in dog behavior, and being able to see the moment a dog tips over is a core body-language skill. Once you can spot it, you stop trying to train a dog who literally cannot learn right then, and you help them recover instead. This builds on reading your dog and connects straight to the threshold concept we use with reactive dogs.
What over threshold means
Below threshold, a dog notices something but can still think, take food, and respond to you. Over threshold, the stress or arousal has flooded their system, the thinking brain goes offline, and they can no longer learn. They are not being stubborn, they genuinely cannot process anything in that state. Recognizing this changes everything about how you respond.
The signs a dog has tipped over
- Refusing food they would happily take when calm. This is the single clearest sign.
- Fixating, locked onto the trigger with a hard stare and a stiff body.
- Not responding to known cues, as if they cannot hear you.
- Frantic or explosive behavior: barking, lunging, spinning, or the opposite, shutting down and freezing.
- A spike in stress signals that no longer helps them cope.
These often follow the early warnings you missed or could not prevent, especially after stress has been stacking up across the day.
What to do when a dog is over threshold
Stop trying to train. Your only goal now is to lower the arousal and help your dog recover. Calmly create distance, break the line of sight to the trigger, and move your dog somewhere easier. Do not add pressure, repeat cues, or correct them, none of it will reach a flooded dog, and it can make things worse.
Prevent it next time
The real work is staying under threshold in the first place: more distance, easier setups, and watching the whole body so you catch the slide early. Reading these signs well is exactly what keeps everyone safe, and it is the foundation of all the gentle work we describe for reactive dogs.
When to get help
If your dog is going over threshold often, escalating, or the behavior frightens you, please get professional support. Our directory of force-free trainers can help, and see when reactivity is bigger than training for the bigger picture. The slide often follows the rungs of the ladder of aggression.
