Aggression is an adaptive behavior that allows a dog to alter his environment in order to increase its chances of survival. Aggression is defined in textbooks as behavior that 1) establishes access to or protects resources, 2)establishes or alters social standing, or 3) defends against perceived threats.
Defense against perceived threats is probably the most common of these three factors in aggressive displays toward humans. Animals have three basic responses to perceived threats; freeze (stand still and hope the threat passes), flee (RUN AWAY!) or fight. This applies to dogs, horses, or humans.
The perception of threat is affected by a number of factors; experience, training, environment, and adaptability to novel situations. Dogs, horses and humans perceive threats differently. One’s place on the food chain has a lot to do with that perception; as prey animals, horses tend to perceive threats in plenty of innocuous situations. For now let’s look at the dog’s perceptions as we understand them.
The world of a dog is split along some very general lines: Scary Things and Not Scary Things. Scary Things are the things that initiate the freeze/flee/fight response. Scary Things are basically, in survival terms, Things That May Eat or Hurt Me.
When a dog is presented with a Scary Thing, a perceived threat, he chooses a response based on his perception of the level of threat and the potential avenues to relieve that threat. Dogs that simply run from a threat don’t present a concern to investigators-they are absent from the conflict. Freezing is likewise a benign response. The choice to fight, however, brings conflict with humans, and the involvement of the investigator.
A dog that chooses the fight response is not limited to an all out fight to the death. Fight, as a response to a perceived threat, is moderated based on the level of threat perceived. Social behavior has evolved to produce a range of postures, vocalizations and actions that other animals perceive as defensive and help avert actual contact.
The initial level of fight is an aggressive display. For dogs this includes body position, raised hackles, eye focus, exposing teeth, growling, and making initial lunges toward a target. If this display mitigates the threat, makes it go away, then the dog deescalates and the situation returns to neutral. If the simple display does not effect a solution, then the conflict can proceed to contact. The dog chooses to escalate, or not, based on the continuing presence of the perceived threat.
Aggressive displays are reinforced by success-if they result in the departure of a Scary Thing then the dog will try them again for another Scary Thing. Continued success means that the behavior will be repeated. But success is strongly based on trial and error. Success is based on a dog’s perception of the chain of cause and effect, a perception that may not reflect human reality.
A classic case of perception reinforcing an aggressive display is a dog’s interaction with a Postal or delivery person. A dog is at home and sees a potential Scary Thing (unfamiliar person) approaching up the walk. The dog starts to bark, posture, and in general show an aggressive display. The delivery person comes to the door and deposits their item. The delivery person walks away, ignoring the dog. The dog, however, is not aware that the delivery person was leaving anyway, and finds that their aggressive display made the Scary Thing go away. Success! The behavior worked.
The next time the delivery person comes up, the dog tries the previously successful behavior. The delivery person leaves, and the dog perceives that it works again! Now we have a successful behavior that has been reinforced by repetition. With enough successes it starts to become a default response to the approach of an unfamiliar person.
Later, the same house is approached by a child selling cookies. The front door is ajar. The dog sees unfamiliar person approach and begins an aggressive display. This time dog is not restrained by the closed door. The approaching child sees the aggressive display and runs. The dog reacts, the dog’s prey/pursuit drive adds in, and we end up with a bitten child.
Preventing this chain of events is a separate topic involving socialization and training, but the end result is that the dog is labeled aggressive. But is it, in the sense of being a dangerous, mean, vicious animal? Not really. Dangerous, mean and vicious are human terms, placing human values on an animal’s behavior, or more exactly, a dog’s response to a perceived threat. In our example we have a dog that has been set up for failure by the combination of a lack of human guidance and misapplication of a survival oriented behavior.
A similar series of events seems to be magnified in dogs that are habitually chained. If a dog feels threatened, their first response is usually to try and flee the Scary Thing. The chain leaves the dog out in the open, with no place to hide, and no place to run. Freezing may work-the dog cowers down and doesn’t respond and the perceived threat may just go away. But the Scary Thing may keep coming-for instance it may be a passing person who has to come close, but not necessarily all the way up to the dog. The dog, fearing that the freezing isn’t working, goes to Plan B: an aggressive display. Sure enough, the Scary Thing goes away. The fact that the Scary Thing (stranger) had no intention of approaching or harming the dog never enters into the equation. Dogs perceive situations as immediate cause and effect. The aggressive display worked.
Constant reinforcement of this success results in a typical fearful chained dog. The person feeding them may be able to approach easily, but others are repelled by the aggressive display. Now, add someone without the ability to recognize the warning signs or who’s recognition abilities are impaired by drugs, alcohol, or a lack of knowledge, and you have an attack.
If the same habitually chained dog gets loose it may be confronted by a Scary Thing while not restrained by the chain. The dog has few tools to handle novel situations due to a lack of socialization, so he defaults to the successful behavior strategy from before-an aggressive display. In this situation the dog is much more likely to attack and the result is a bite. Is this a vicious dog? We may perceive it as such, but the behavior is the result of a series of events that has its roots in the human behind the chain. In both cases there has been a human cost and the result is a need for control, management, and responsibility.