The Ethological Explanation of Aggression

The Ethological Explanation of Aggression

Ethology: The scientific study of animal behaviour in a natural environment, viewing behaviour as an evolutionarily adaptive trait. This explanation suggests that aggression has an adaptive function.

Adaptive functions: Aggression is an instinct- it does not need to be learnt. It is innate and therefore genetically determined. Aggressive behaviours are adaptive because they are helpful to the survival of a species. In examples of aggression, defeated animals are rarely killed. This is adaptive, as the defeated animal will move elsewhere, spreading out the species over a larger area and reducing competition pressure for resources. Aggression is also used to establish dominance hierarchies, allowing the animal to have a high status and therefore access to more resources and potential mates.

The Ethological Explanation of Aggression, figure 1

Ritualistic aggression: Lorenz observed that animals rarely engage in actual physical fighting. Instead, time is spent on ritualistic ‘signals’ (e.g. facial expressions). Also, defeated animals show signs of ‘appeasement’ (acceptance of defeat), and are usually not killed. These behaviours are adaptive, because the injury or death of an animal reduces its population numbers and threatens the species’ existence.

Innate releasing mechanisms and fixed action patterns: An innate releasing mechanism (IRM) is an inbuilt physiological process which gets triggered by an external stimulus. The IRM releases a specific sequence of behaviours called a fixed action pattern, which is:

  • An unchanging sequence of behaviour
  • The same for every animal of that species
  • Unaffected by learning
  • Cannot be altered before completion (‘ballistic’)
  • Only occurs in a specific situation
  • Response to a specific stimulus

Tinbergen (1951) investigated sticklebacks, which develop red areas on their underbellies during mating season, and become aggressive towards males entering their territories. He found that, when presented with wooden models of various shapes, male sticklebacks would aggressively display and attack the model if there was a red area underneath it (even if it looked nothing like a fish). They did not attack stickleback-shaped models if there was no red underbelly.


  • There is research support into role of limbic system in triggering aggression, supporting the suggestion that aggression may be a primitive, innate instinct which is therefore adaptive.
  • There is evidence against idea that aggressive displays do not result in physical violence. During the ‘four-year war’ at a national park in Tanzania, Goodall (2010) observed examples of violent, aggressive acts by chimpanzees towards each other, even when the opponent showed clear signals of defeat. This challenges the suggestion that aggressive displays do not lead to actual aggression.
  • Generalising these explanations to humans is difficult, as other processes such as the environment, thought processes and so on are likely to have an influence on aggressive behaviour as well as instinctual factors proposed by the ethological explanation.

Evolutionary Explanations of Human Aggression

Key Terms:

  • Adaptive: Behaviours and physical characteristics are adaptive if they are useful to the survival of a species. Organisms with certain physical or psychological traits are more likely to be reproductively successful.
  • Environment of Evolutionary Adaptation (EEA): The time when a species first emerged as a distinct species from its ancestor. The physical and behavioural characteristics of a species will be suited to the EEA. For humans, this was over 10,000 years ago when they were hunter-gatherers on the African savannah.
  • Genome lag: The idea that some behaviour is no longer adaptive because genetic changes over thousands of generations have proceeded much slower than changes in our environment. Behaviours which were useful to survival in the EEA are still present today (although they may be expressed in different ways).

The Ethological Explanation of Aggression, figure 1

Evolutionary explanation of jealousy: Daly and Wilson (1988) claim that men have evolved several different strategies to deter their female partners from committing adultery. These range from vigilance to violence, but all are fuelled by male sexual jealousy, which is more common than female sexual jealousy. Men can never be entirely certain that they are the fathers of their children, so are always at risk of cuckoldry (raising a child not their own). If a man is cuckolded, he might unwittingly invest his resources in offspring that are not his own, which isn’t conducive to ensuring the survival of his own genes. Sexual jealousy and aggression arising from it is therefore an evolved mechanism to prevent a mate from sexual infidelity and cuckoldry.

Daly and Wilson suggest that males have a number of mate retention strategies that have evolved specifically for the purpose of keeping a mate. They can be categorised as direct guarding (restricting a partner’s autonomy; a form of passive aggression), and negative inducements (violence or threats of violence to prevent straying). According to the theory, those women who are perceived by their partner to be threatening infidelity should be more at risk of violence than those who are not. Camilleri (2004) found that sexual assault of a female by her male partner was directly linked with the perceived risk of her infidelity.

A study by Shackelford et al (2005) shows how sexual jealousy is linked with aggression. Men and women completed different questionnaires- men completed the ‘Mate Retention Inventory’, measuring the amount of times mate retention strategies had been used over the past year. Women completed the ‘Spouse Influence Report’, measuring how often they had been victims of violent acts by their partner. There was a strong positive correlation between the male’s score on the Mate Retention Inventory and the female’s score on the Spouse Influence Report, suggesting a link between the two.

The Ethological Explanation of Aggression, figure 2

Evolutionary explanation of bullying: It is argued that characteristics of bullying behaviour in males are attractive to the opposite sex, as it suggests the ability to dominate, move up a social hierarchy, and accrue resources. Bullying also removes threats to status and potential for competition for mates. In females, bullying more often takes place within a relationship, having the function of controlling the male partner and ensuring he continues to provide resources. Bullying behaviour in both sexes can therefore be seen as adaptive.


  • The evolutionary explanation is supported by research, such as Shackelford et al (2005). However, there are potential problems with drawing conclusions from research in this area, as it is (necessarily) correlational rather than causal. This weakens the suggestion that evolutionary factors have caused aggressive behaviours.
  • The evolutionary approach can explain gender differences in aggression. Women are less physically aggressive than men, according to this theory, as physical aggression would have been far costlier for the female in the EEA (as they would be raising children, whose survival would also be put at risk). Those females who used different strategies to resolve conflicts would be at a survival advantage. This is a strength, as gender differences in aggression are accounted for.
  • Evolutionary explanations are useful for considering how to tackle bullying behaviour in a real-world context, by increasing the costs of bullying and rewarding alternative pro-social behaviour, therefore reducing the rewards gained from bullying. This real-world application of the theory is therefore a strength.

Frustration-Aggression Hypothesis

Social psychological explanations attempt to explain people’s experience of aggression, and the events which may trigger it. They include frustration-aggression, social learning theory and de-individuation.

Frustration-aggression: Dollard (1939) suggested that frustration always leads to aggression, and aggression is always the result of frustration. Frustration refers to the blocking of a goal you want to achieve, which creates an aggressive drive. This must be released by an aggressive act, or a violent fantasy. In doing this, the aggressive drive is satisfied and so reduced. Aggression is not always directed against the source of frustration, for a few reasons. It may be an ‘abstract’ cause (anger over the state of the economy), the source may be too powerful (a teacher or boss), or the cause of frustration may not be present at the time. In these circumstances, aggression is displaced onto a weaker, available alternative (a younger sibling). This explanation overlaps with psychodynamic concepts, such as catharsis (releasing repressed emotions).

Research: Geen (1968) found that participants gave more shocks to a confederate when the confederates were insulting, and stopping them from completing a task.

Berkowitz and LePage (1967) found that environmental cues created a readiness for aggression (for example, the presence of a weapon). Participants gave stronger shocks to a confederate when a gun was on the table next to the shock machine. This suggests that the aggressive drive can be triggered by something in the environment.


  • The concept of displaced aggression is supported by a meta-analysis- Marcus-Newhall et al (2000) found that participants who were provoked but could not retaliate against the source of frustration were much more likely to aggress against an innocent party than people not provoked. This supports the theory as it shows that displaced aggression does occur, as predicted.
  • The theory is weakened by Bushman (2002). In the study, it was found that participants who hit a punchbag became more angry and aggressive than those that sat and did nothing. This weakens the theory because it suggests that venting aggression does not reduce the aggressive drive.
  • The theory is weakened by Berkowitz’s suggestion. Berkowitz found by looking at research that frustration is only one source of aggression, which is triggered by negative feelings generally. This weakens the original hypothesis because the suggestion that only frustration results in aggression is over-simplistic.