Know aggression !!!

Aggression has in relation to pain and an understanding of aggression is important for those working with animals in distress. Aggression is not a unitary phenomenon. Clearly the emotion underlying predatory behaviour (sometimes referred to as predatory aggression) is quite different from that underlying defense of a resource from conspecific (affective aggression), or bouts of ‘apparent aggression’ arising during acts of play. These three types of activity belong to functionally different behavioural systems and are directed towards very different goals. While they might all (in the case of carnivores in particular) share the potential to cause harm to another individual, it is potentially confusing to link them with each other through the use of the term aggression in their description. Injury that arises during play might be a result of aggressive play, but that does not make it a form aggression, it is first and foremost a form of play.

The further subdivision of affective aggression is of questionable value. It may be divided according to descriptive context, such as ‘owner directed aggression’, or according to motivation/mechanism, such as ‘defensive aggression’. Both have their advantages and disadvantages. For example, contextual labels have both the advantage and disadvantage of not implying anything about motivation and so might  be quite reliable terms, but do not link with underlying mechanism or treatments aimed at addressing the cause  in a reliable way. This is something that is frequently overlooked in the literature. The main problem with motivational descriptions is knowing with confidence what the precise motivation is.

Aggressive displays should be distinguished from aggressiveness, which can be used to describe both the mood and temperamental trait relating to the propensity to show aggression when environmental circumstances dictate it might be used. Animals may become temperamentally more aggressive if they are in chronic pain. This may resolve once the pain is eliminated, but the animal may also learn to use displays of aggression in a wider range of contexts as a result of this episode. In this situation specialist assistance should be sought to help resolve the problem.

The expression of aggression depends on a range of underlying external contingencies as well as internal predispositions. Historically, psychology has focused on the external factors producing aggression and these are well summarised by Archer (1976).

Namely aggression may occur when:

1. A territorial boundary is crossed.

2. The personal space is entered.

3. The body is touched.

4. The animal is faced by uncertainty/novelty in the environment.

5. An expected reward is absent or withdrawn.

6. An expected reward is reduced.

7. Behaviour is frustrated from being executed – this includes the application of intended punishment to an animal that is already nervous.

These situations may all occur when a physiotherapist is trying to treat a patient and are perceived at a time of potentially aversive change (i.e. an unpleasant near-future). A number of individual factors determine whether overt aggression rather than freezing, flight or some form of appeasement is offered.

These include the following:

1. The emotional state (mood) of the animal– Fearfulness in the absence of an easy route for escape, greatly increases the probability that aggression will be used, but more generally there are a wide range of factors which can increase irritability (an enhanced predisposition towards aggression), including low grade chronic/subclinical pain. This is particularly worth investigating when the pattern is not entirely predictable, and probably underestimated in veterinary practice.

2. The animal’s appraisal of the situation– This depends on the animal’s perceived ability to win the contest, the value of any resource that is being disputed and the expected cost of defense. Learning can be very important in this, as an owner who always gives way to their dog will be perceived both as an inferior competitor, and as an individual who does not put up much of a fight. It is perhaps for this reason that clinicians and therapists are often able to handle an animal in a way that would be impossible for the owner. This can obviously be to the physiotherapist’s advantage, but must also be taken into consideration when making recommendations for treatment. Owners may not only lack the skill to undertake certain procedures in the home, but also the necessary authority. While handouts, such as those by Landsberget al. (2001), can be very useful in the management of such problems, they should not be used without understanding the fundamental nature of the problem faced. Therapists should also consider the potential need for specialist intervention in handling aggression, and ensure the risks to others of injury from an aggressive episode are minimised.

This involves:

•Informing owners of their responsibility to prevent injury to others.

•Advising owners to avoid situations that are likely to exacerbate the problem. This may include identifiable trigger stimuli, such as approach towards a particularly painful area, uncertainty in handling the animal, frustrating or fearful situations.

•The animal should not be approached when it has no opportunity to retreat.

•If it is safe to do so, the owner should be encouraged to muzzle-train an aggressive dog away from arousing or dangerous environments. A basket muzzle is preferable to a nylon one, as it allows the dog to pant and drink but not bite while it is on. The most common problem with muzzles is that they are only used when the dog is already showing aggression and will resent restraint. So training should begin away from distractions and associated with rewards placed in the muzzle. Once trained, the dog should be muzzled before the problem arises, i.e. before arriving at the treatment center.

Reference: Animal Physiotherapy: Assessment, Treatment and Rehabilitation of Animals

Edited by Catherine M. McGowan, Lesley Goff, Narelle Stubbs.