Understanding aggression: How does it develop?

by Rachel Casey

Why is Your Dog Aggressive?

Aggression in dogs is often misunderstood. It’s difficult not to take it personally if your dog growls at you. And it’s upsetting if he or she barks at another dog. In the past, it was thought that dogs became aggressive because they were trying to be ‘dominant’ or achieve social status. But we now know that aggression has nothing to do with status. In fact, in almost every case of aggression the behaviour starts through fear. Just like us, dogs have three options to deal with a scary social situation: indicate that they want to avoid conflict (showing behaviours known as ‘appeasement signals’), avoid contact by withdrawing or hiding, or show aggression to get the other guy to move away. Dogs learn which strategy ‘ works’ to avoid the threat, and will be more likely to do the same the next time they are in the same situation.

This case example will help explain how an aggressive response may develop over time.  Let's imaging a young Springer Spaniel bitch (let’s call her 'Ellie’) who is scared of fireworks. It is just after 5th November, and when she went out into the garden last thing yesterday night to go to the toilet, a firework went off further down the street. From this experience, Ellie has learnt that going into the garden when it is dark is pretty scary (but going out in the daytime is fine). She no longer wants to go out into the garden at night before her owners go to bed. But her owners particularly want her to go into the garden last thing, as otherwise she may mess in the kitchen overnight. They haven’t connected her reluctance to go out with the fireworks, and consider her new habit of trying to avoid going out rather irritating.

Understandably, from their point of view, they insist she goes outside, and grab her by the collar to guide her outside. For Ellie going outside in the dark is a life-threatening situation, and she wants to avoid this at all costs. Initially she might show appeasement behaviours to try and get out of conflict with her owners. But in this type of situation owners often ignore these. She might wriggle free and go and hide under the table, but her owners are also likely to go and get her out again. What she learns is that neither appeasement nor avoidance ‘work’ to escape the awfulness of having to go outside. So in a panic she tries her only other option: aggression. When dogs growl or snap for the first time owners are often very surprised or shocked and back away, even if only momentarily. If this happened a few times, Ellie would start to learn that in this situation, her best option to avoid what she is scared of is to growl at her beloved owners.

Over repeated occasions, an aggressive response like this becomes more and more well established. Dogs like Ellie will gradually learn the specific events that predict the threat (e.g. an owner’s hand reaching for their collar) and will often start to become aggressive more rapidly on identifying these cues. They will also become more confident that aggression is likely to ‘work’ in this situation, progressively appearing less fearful and instead have a ‘confident’ body posture.

As the behaviour develops, it can look very confident or 'offensive'. However, if we remember how the behaviour started, it is clearly a defensive response to a perceived threat which the dog has developed into a (very effective) way of avoiding something they find scary. Once this type of avoidance response is well established, the dog will have a strong expectation that it will be successful, and trying to interrupt it can be very dangerous.

The earlier a problem is identified and good advice provided, the easier it is to resolve - so it's vital to seek specialist help as soon as a problem occurs.