Ethological explanation Flashcards
(15 cards)
What does the ecological explanation suggest?
The main function of aggression is adaptive
Why is aggressive beneficial for survival?
A defeated animal is rarely killed but rather forced to establish territory elsewhere
Members of species spread out over a wider area and have to discover resources in different place
Reducing competition pressure and the possibility of starvation
What are dominance hierarchies?
Male chimpanzees use aggression to climb their troops hierarchy
Dominance gives special status - like mating rights over females
Humans too
What did Pettit et al study about hierarchies?
Studied young children
Observed how aggression played important role in development of dominance hierarchies
Would be adaptive because dominance over others brings benefits such as access to resources
What is ritualistic aggression?
A ritual is a series of behaviours carried out in a set order
What did Lorenz observe around ritualistic aggression?
Observed fights between animals of the same species produced little actual physical damage
Most aggressive - prolonged period of ritualistic signalling (facial expressions of threat, displaying claws or teeth)
What did Lorenz also find around ritual appeasement?
Instra-species aggressive confrontation end with ritual appeasement displays
Indicating acceptance of defeat and inhibit further aggressive behaviour in the victor
Preventing any damage to looser
Wolf at end with expose neck to victor - submissive appeasement gesture making itself vulnerable to a single bite to its jugular vein
Adaptive - if every aggressive acounter ended with the death of one of the combatant, that could threaten existence of the species
What is innate releasing mechanism?
Inbuilt psychological process or structure
Eg. network of neurons in the brain
An environment stimulus (facial expression) trigger inbuilt psychological process which then releases specific sequence of behaviours
Fixed action pattern
What did Lea say about the fixed action patterns?
6 main features
1 - Stereotyped, or relatively unchanging sequence of behaviours
2 - Universal, because the same behaviour is found in every individual of a species
3 - Unaffected by learning, the same for every individual regardless of experience
4 - Ballistic, once the behaviour is triggered it follows an inevitable course and cannot be altered before it is completed
5 - Single purpose, the behaviour only occurs in a specific function and not in any other
6 - Response to an identifiable specific sign stimulus
What was Tinbergens procedure?
Male stickle back
Highly territorial during spring mating season, also developed red spot on their underbelly
If another male enters territory - sequence of highly-stereotyped aggressive behaviours initiated (FAP)
Sign stimulus that triggers the innate releasing mechanism is the sight of the red spot
Presented stickleback with a series of wooden models to different shapes
What did Tinbergens research find?
Regardless of shape
If the model had a red spot the male stickle back would aggressively display and even attack it
If no red spot there was no aggression
Even if model looked realistically like a stickleback
Also found that these aggressive FAPs were unchanging from one encounter to another
Once triggered the FAP always ran its course to completion without any further stimulus
What is a counterpoint to research support?
Aggressive behaviour differs from one culture to another, sometimes even within same country
Nisbett
One type of homocide was ore common amongst white men in southern united states than in norther states
Reactive aggression is response to threats from someone else
Difference caused by a culture of honour is southern US
Less prevalent in the north - why reactive aggression homocide rates are lower there
Comes from a learned social norm rather than being instinctive
Culture can override innate predispositions, hard for ethological theory to explain
What is a strength of the ethological explanation?
Research support related to genetics and evolution
Brunner et al
Showed that one gene (MAOA-L gene) is closely associated with aggressive behaviour in humans
Twin and adoption - showed significant genetic component to aggression in humans
Line of research point toward an innate basis to aggressive behaviour
Suggests the ethological approach is correct in claiming that aggression is genetically determined, heritable and adaptive
What is a limitation of ritualistic aggression?
Aggression against members of same species is not just ritualistic
Goodall
Observed a four year war
Male chimps from one community killed all the members of another group
Done in systematic way
Victim would be held down by rival chimps whilst others hit it in an attack lasting many minutes
Violence continued even thought victims offered appeasement signals.
Signals did not inhibit aggressive behaviour of the attackers as predicted by the ethological explanation.
Challenging ethological view that same species aggression has evolved into a self limiting and relatively harmless ritual
What is a limitation of Lorenz origional view of FAPS ?
Outdated
Saw FAPS and innate and unchanging
Hunt
Pointed out FAPS are greatly influenced by environmental factors and learning experiences
Aggressive FAP is typically made up of several behaviours in a series of During of each behaviour varies from one individual to another
Are modifiable by experience, many ethologists now prefer term ‘model behaviour pattern’ to reflect this
Patterns of aggressive behaviour are much more flexible than Lorenz thought especially in humans
