The ethological explanation of aggression Flashcards
What are the ethological explanations of aggression?
Innate releasing mechanisms
Fixed action patterns
What do Ethologists say that aggressive responses in animals are?
Fixed actions patterns
What are Fixed action patterns?
Ethologists state that aggressive responses in animals are fixed action patterns which are:
Innate
Stereotyped
Universal
Have specific triggers known as ‘sign stimuli’
How do Fixed action patterns operate?
Fixed action patterns operate around a hydraulic model:
Aggressive energy builds up in the animal.
A perceived threat causes the FAP to be automatically released.
This release causes energy levels to decline and the FAP cannot be repeated until energy levels rise again.
What is an example of a fixed action potential in animals?
Tintenberg studying the FAP in sticklebacks, found that male sticklebacks exhibit a FAP of aggressive behaviours upon another male entering their territory.
The sign stimulus here is the male’s red underbelly. If this red sign stimulus is covered up the FAP of aggression will not occur.
Tintenberg used the term innate realising mechanism to refer to part of the brain which is stimulated by a sign sign stumbles and activates the FAP of aggression.
What is a innate releasing mechanism?
The part of the brain which is stimulated by a sign stimulus and activates the FAP of aggression.
Do most animals fixed action potential contain a ritualised form of aggressive display?
Contains a ritualised form of aggressive display where animals make physical and verbal threat displays e.g. gorilla beating chest and howling which allows the combatants to assess their opponent’s chances of winning and if judged appropriate, back down without engaging in actual combat and suffering injury.
For example, when wolves fight if a wolf recognises that they are losing they will expose their threat to their opponent to indicate submission. This submission sign-stimulus prevents the dominant wolf from attacking further. Thus, for nearly all animals, ritualised displays of aggression and submission stimulus signs prevent combatants dying as a result of aggression and conflict is resolved.
What evidence is there supporting the concept of ritualised aggression?
Anthropologists claim to have found evidence of such ritualised aggression in traditional, pre-modern societies. For example, Chagnon 92 states that amongst the Amazonian Yanomamo, ritualised club fighting allows conflicts to be settled without fatalities.
How did Lorenz say that animal aggression served construction purposes?
For example intraspecies aggression has the effect of disturbing animals through an area that makes most effective use of resources such as food and mates. From an evolutionary perspective, aggression also maximises survival and reproduction success, competition for males and passing on genes to the next generation.
What evidence is there supporting Lorenz’s claim that nail aggression is largely ritualised?
Many species do deliberately kill conspecifics such as lions. However, this aggression may have alternative functions.
Male lions who have taken over a new pride of lions will kill existing cubs to bring females back to oestrus so that they can pass not their genes. Also cannibalism in chips may occur simply to serve the function of additional dietary protein.
What are critics of Lorenz concept on aggressive behaviours being innate and fixed?
Critics have argued that Lorenz under-estimated the role that environmental factors can play in species’ aggressive behaviours -therefore, they are not as fixed and innate as he suggested. There also seem to be small variations in aggressive behaviours shown by different species members in different parts of the world so behaviours may be less universal than he claimed.
