Aggression: forms, causes, and functions in humans and animals

Aggressive behavior is widespread in the animal kingdom. Behavioural biologists interpret it as serving direct competition for resources or food (interspecific competition and intraspecific competition), territorial defence, the establishment or modification of a hierarchy and also competition for a possible sexual partner. Grabbing a prey animal for food is also associated with a form of aggression in animals, whereas in humans, techniques for killing prey were used early on (see hunter-gatherer). Aggressive behavior in the proper sense is often referred to by ethologists as agonistic behavior or as attacking and threatening behavior and is associated with specific triggers ("key stimuli"). To regulate aggressive impulses, animals and humans have the instinctively predisposed inhibition of aggression.

In dogs, Nora Brede, Ute Heberer and Normen Mrozinski distinguish between resource-related, status-related, socially motivated, sexually motivated, territorial, redirected/readdressed, fear-related, learned and otherwise motivated aggression as well as mixed forms with simultaneous occurrence of different forms of aggression. Resource-related aggression includes offensive or defensive-aggressive defense of food, toys, or sleeping space. In addition, an overabundance of resources - such as when a dog placed from a foreign shelter experiences an unexpected abundance of resources - can lead the dog to misinterpret its status. In part, status conflicts are also played out over resources. Status-related aggression (also called dominance aggression or control-related aggression) is directed against "competitors" in the dog's own social association and manifests itself, for example, in the dog restricting its owner spatially. Socially motivated aggression is shown by dogs only in connection with a social partner, for example in the form of leash aggression, a fence aggression together with another dog, or a defense of the social partner or a defense of other interaction partners. Sexually motivated aggression can be related to the heat of a bitch or the imposition of a male dog. Special forms of aggressive behaviour include aggression due to pain or illness.

Human aggression is a behavior that occurs either with the intention of harming other people or to lower them in their ranking status. One can distinguish emotional and instrumental aggression. In the first case, the aggressive behavior is a reaction to experienced physical or psychological suffering, in the second case it is a rational action, a method of achieving a particular goal.

Aggressive behaviour is closely related to behaviours such as attack, flight and defence. The strength of aggressive behaviour can be attributed to the interaction of an activated inner readiness (aggressiveness) and an external situation that triggers aggression.

In the context of human behaviour, aggression can manifest itself in verbal (defamation, insult, reproach), psychological (exclusion) or physical attacks on people, groups of people and property (damage to property) or - as in the animal kingdom - in threatening behaviour, "comment fights" and ritualised confrontations, for example in sport, games or at work (rivalry).

In international law, aggression, as opposed to defence, refers to the first use of force in a dispute between states, peoples and ethnic groups.

Aggression is usually associated with maladaptive, destructive, and destructive behaviors; these are usually characterized (according to Schmidt-Mummendey 1983) in humans by the following factors:

• from the injury,
• from the intention (intention, directionality),
• from the norm deviation.

In humans, "aggressive behaviour" is primarily understood to mean direct or indirect physical and/or psychological harm to a living being or damage to an object (according to Merz, F. 1965); regardless of what the ultimate goal of this action is (according to Felson, R. B. 1984). What is important here is the intention, regardless of whether or not damage occurs (for example, if the victim evades at the last second). Often the addition is used that the harmed living being is motivated to avoid the treatment (see also Volenti non fit iniuria - No injustice is done to the consenting party).

Forms of aggression are:

1. open, physical form (towards living beings): hitting, killing, physically threatening, autoaggressive (directed against oneself)
2. open, physical form (towards inanimate objects): deliberate contamination, deliberate careless treatment of objects, damage to property (including vandalism) and destruction of objects,
3. Open, verbal or non-verbal form: Insulting, mocking, gestures and facial expressions, shouting, crude and deliberately vulgar language styles and manners,
4. covert form: Fantasies,
5. indirect form: damage to property (of objects belonging to the person(s) against whom the aggression is directed), defamation, bullying, creating barriers,
6. emotional form: as a result of stress, anger, resentment, hatred, envy.

More broadly, aggression refers to working, competing, or acting assertively as an essential form of "taking charge." These types of actions have nothing to do with harm or injury compared to the narrower definition.

"By aggression is meant any behavior that is essentially the opposite of passivity and restraint" (Bach & Goldberg 1974, p. 14, cited in Nolting 2000, p. 24).

"Aggression is everything that seeks to dissolve an inner tension by activity, initially by muscular force" (Mitscherlich 1969 a, p. 12, quoted in Nolting 2000, p. 24).

"We define aggression as that disposition and energy inherent in man which expresses itself originally and later in a wide variety of individual and collective, socially learned and socially mediated forms ranging from self-assertion to cruelty." (Heinelt, 1982.)

Other (motivational) distinguishing features:

1. positive (e.g., in sports) vs. negative,
2. spontaneous vs. reactive vs. commanded,
3. serious vs. playful.

Typical aggression targets include:

1. asserting one's own wishes and interests that conflict with the wishes of others,
2. Find attention by others (ranking),
3. Response to aggression by others (defense, self-defense),
4. Retribution for acts of aggression suffered (revenge).