The ethological explanation of aggression Flashcards
What is ethology?
- ethology is the study of animal behaviour and extrapolating it to human behaviour
What are the main assumptions of the ethological explanation?
- The ethological explanation suggests that the main function of aggression is adaptive
- It assumes that aggression is beneficial as the defeated animal is rarely killed but rather is forced to establish territory elsewhere
- This means that members of a species are widely spread out, reducing intraspecific competition and reducing chances of starvation
- It also helps to establish dominance which can give animals special status and access to mates, spreading their advantageous alleles
What is ritualistic aggression?
- A ritual is a series of behaviors carried out in a set order
What did lorenz say about ritualistic aggression
- Lorenz observed that animals of the same species show little physical damage and instead show ritualistic signalling such as displaying teeth, growling and appearing larger
- Lorenz also stated that intra - species end with ritual appeasement which indicates defeat
- For example, wolves show their opponent their jugular vein indicating vunerability
What is an innate releasing mechanism
- A biological structure or process in the brain which is activated by an external stimulus that in turn triggers a fixed action pattern
What is a fixed action pattern
- A sequence of stereotyped preprogrammed behaviours triggered by an innate releasing mechanism
What are the six main features of fixed action patterns
-Stereotyped: Relatively unchanging sequences of behaviours
- Universal: The same behaviour is found in every individual of a species
- Unaffected by learning: The same for every individual regardless of experience
- Ballistic: Once the behaviour is triggered, it follows an inevitable course of behaviour and can not be altered before it is completed
- Single - purpose: The behaviour only occurs in a specific situation and not another
- Response: A response to an identifiable specific sign stimuli
What is the procedure of Tinbergens research
- Male sticklebacks are highly territorial during spring mating season, when they also develop a red spot on their underbelly
- If another male enters their territory, a sequence of highly - stereotyped behaviour is initiated (FAP).
- the sign stimulus that triggers the IRM is the sight of the red spot
- Niko Tinbergen presented sticklebacks with a series of wooden models of different shapes
- Some were very accurate to a stickleback and some were very innacurate
What were the findings of Tinbergens research
- Regardless of shape, if the model had a red spot the male stickleback would aggressively display and attack it
- if there was no red spot, even if the model was realistic, there was no attack
- Tinbergen found that the FAP was unchanging from one encounter and ran its course to completion without any further stimulus
What is a strength of ethological explanations of aggression
- there is research support from research related to genetics and evolution
- For example, the MAOA _ L gene is closely related to aggressove behaviour
- Additionally, Twin and adoption studies showed a sigficant concordance with genetics and aggression
- This shows that aggressive behaviour is innate and the ethological approach is correct in claiming that aggression is genetically determined, heritable and adaptive
Counterpoint: Aggressive behaviour differs from one culture to another. Richard Nisbett (1993) found that one type of homicide was more common amongst white men in the south compared to the north. Reactive aggression is a response to threats from someone else. Nisbett concluded that the difference was caused by a culture of honour in the south. This is less prevalent in the north, which is why reactive aggression rates is lower there, This shows that aggression may not be innate and is instead cultural
What is a limitation of ethological explanations
- One limitation is that aggression agaisnt members of the same species may not be ritualistic
- Jane Goodall obeserved a war between male chimps where one community killed members of another group systematically
- One one occassion, a victim was held down and hit by rival chimps.This violence continued even after appeasement signals
- This challenges the ethological view of same species aggression is not harmless
What is a limitation of FAPs
- A limitation is that Lorenz original view of FAPs is outdated
- He saw that FAPs are innate and unchanging, however, Morton Hunt pointed out that FAPs are influenced by environmental factors and learning experiences.
- For instance, the duration of behaviours differ from each individual and are modifiable by experience
- ethologists now prefer the term of modal behavioural pattern to reflect this
- This shows that patterns of aggressive behaviour are much more flexible than Lorenz originally thought
