Ethological Explanation of Aggression Flashcards
what is an ethological explanation?
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an explanation that stresses the adaptive value of animal behaviours
ethologists study the behaviour patterns of animals in their natural environments
what does the ethological explanation of aggression suggest?
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ethologists study the behaviour patterns shown by animals in natural environments
they recognise that while the potential for aggression may be innate, actual aggressive behaviour is elicited by specific stimuli in the environment known as releases
Lorenz believed that aggression has survival value to animals — for example, intraspecies aggression serves to distribute individuals within a group to make the most efficient use of available resources such as food, access to mates and territory
he argues that aggressive impulses in humans are largely innate
features of the ethological explanation of aggression
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- fixed action patterns (FAPs)
- innate releasing mechanisms
- ritualistic aggression
- wolves and doves
- the hydraulic model
fixed action patterns (FAPs)
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the ethological explanation states that all members of the same species have a repertoire of stereotyped behaviours which occur in specific conditions (i.e. in response to specific triggers)
these behaviours do not require learning as they are innate
ethologist Niko Tinbergen called these innate behaviours fixed action patterns (FAPs)
aggression is a FAP
characteristics of FAPs
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characteristics of FAPs (Lea, 1984)…
- stereotyped — the behaviour always occurs in the same way
- universal — the behaviour is the same in all conspecifics
- independent of individual experience — the behaviour is innate with no learning involved
- ballistic — when triggered, the FAP cannot be changed or stopped
- specific triggers — each FAP has a specific trigger known as a sign stimulus
innate releasing mechanisms
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FAPs are produced by a neural mechanism known as an innate releasing mechanism (IRM) and are triggered by a specific stimulus known as a sign stimulus
IRM = a neural network that, when stimulated by the presence of a sign stimulus, communicates with motor control circuits to activate the fixed action pattern associated with that sign stimulus
the IRM receives its input from sensory recognition circuits that are stimulated by the presence of the sign stimulus
the IRM then communicates with the motor control circuits to activate and release the FAP associated with that sign stimulus
Tinbergen’s research with stickleback fish showed that a male stickleback fish will produce a fixed sequence of aggressive actions when another male enters its territory
the sign stimulus is the sight of another male’s distinctive red underbelly, which activates an IRM and then causes a male to release the FAP of aggression towards the other male
if this is covered up, the intruder is not attacked
ritualistic aggression
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ethologists have shown that not all aggressive behaviour involves fighting, but may be ritualised in the form of threat displays
these are important for contestants because they help individuals to assess their relative strength before deciding to escalate a conflict
as a result, they make costly and dangerous physical aggression less likely to occur
for example, mail gorillas use a variety of vocalisations such as hooting and gestures such as chest pounding to intimidate an opponent without the need for physical contact
threat displays like this are intended to make an opponent back down and are the last step before an animal either fights or submits and leaves
anthropologists have found evidence of the use of ritualised aggression in tribal warfare in human cultures
Gardner et al (1968) describe how the Dani of New Guinea engaged in highly ritualised patterns of intergroup hostility
Fox (1978) also found evidence of highly ritualised ‘fighting’ among males of the Gaelic speaking Tory island off the coast of Ireland, where threat displays appear to take the place of actual aggression
wolves and doves
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some species have evolved fearsome weapons that make them effective hunters. for example, wolves have powerful jaws and strong teeth
Lorenz (1952) claimed that such species must also have instinctive inhibitions that prevent them using these weapons against members of their own species
when two wolves fight, if the individual who is losing submissively exposes its neck to its adversary, then instinctive inhibitions prevent the dominant animal from continuing the fight
Lorenz argued that non-hunting species such as doves have no such powerful natural weapons and therefore have not developed the same inhibitions against hurting their own kind
he believed this comparison had implications for the human species — humans are more like the dove than the wolf when it comes to dealing with other human beings
we do not have powerful natural weapons like wolves do and therefore have had no need to develop strong instinctive inhibitions against killing one another
science and technology has far outpaced our biological evolution — we have developed weapons of tremendous destructive power without also developing instinctive inhibitions against using them
the hydraulic model
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each FAP has a reservoir of action specific energy (ASE) that builds up over time
the appropriate sign stimulus causes the IRM to release this energy and the animal then performs the FAP
after performing the FAP, the reservoir of ASE is empty and the behaviour cannot be repeated until the ASE has built up again
this is sometimes called the hydraulic model of instinctive behaviour (Lorenz, 1950)
in the model, ASE is represented by fluid in a reservoir that builds up and places pressure on a spring (IRM) which is also being pulled by weights (the sign stimulus)
together, this leads to the release of the FAP when ASE is high enough and the appropriate sign stimulus is present
however, the FAP may also be produced in the absence of the sign stimulus if the level of ASE is sufficiently high (meaning a behaviour can occur spontaneously)
x4 evaluation points
problems with generalising to humans
the benefits of ritualised aggression
species killing members of their own species is not that rare
criticism of an instinctive view of aggression
EVALUATION
problems with generalising to humans
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ethological explanations of aggression study the behaviour patterns shown by animals and view aggression in terms of these animals
therefore, it is not appropriate to generalise findings or theories from such research to human beings
Eibl-Eibesfeldt (1972) did identify a number of human FAPs and human universals such as smiling as a sign of greeting
however, because the environment in which humans exist changes so rapidly, it is suggested that FAPs such as aggression are no longer adaptive in modern times
the flexibility of human behaviour and the ability to respond to an ever-changing environment has proved more effective than the production of stereotypical, fixed patterns of behaviour
this suggests that although animals may respond aggressively to specific sign stimuli, human behaviour is far more varied and less predictable
therefore, ethological explanations of aggression have limited usefulness in explaining aggressive behaviour in humans
EVALUATION
the benefits of ritualised aggression
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in animals, the main advantage of ritualised aggression is that it prevents conflicts escalating into potentially dangerous physical aggression
anthropological evidence suggests that this advantage is also evident in human cultures
for example, Chagnon (1992) describes how among the Yanomamo people of South America, chest pounding and club fighting contests can settle a conflict before it escalates into more extreme violence
similarly, Hoebel (1967) found that among Inuit Eskimos, song duels are used to settle grudges and disputes
this shows that even in moderately to highly violent cultures such as the Yanomamo, rituals have the effect of reducing actual aggression and preventing injury or death of the combatants
this demonstrates that ethological explanations of aggression can apply to human beings as similar ritualistic aggression is shown in both animals and human cultures
EVALUATION
species killing members of their own species is not that rare
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a problem for the ethological explanation of aggression concerns the claim that predator species must also have instinctive inhibitions that prevent them using their natural weapons against members of their own species
however, this argument that among such species the killing of members of the same species would occur only by accident is not entirely accurate and counter evidence can be found in animal behaviour
in some predator species, the killing of conspecifics is more systematic than accidental
for example, male lions will kill off the cubs of other males and male chimpanzees will routinely kill members of another group
these findings pose a challenge for the ethological explanation of aggression as they cast doubt on the claim that much of animal aggression is ritualistic rather than real
EVALUATION
criticism of an instinctive view of aggression
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Lehrman (1953) criticised Lorenz’s instinctual explanation of aggressive behaviour
he believed that Lorenz had underestimated the role of environmental factors in the development of species-typical aggressive behaviour patterns
these environmental factors, largely the result of learning and experience, interact with innate factors in more complex ways
nowadays, the term ‘fixed action pattern’ tends not to be used within ethology and has been replaced by the time ‘behaviour pattern’ to reflect the fact that these are not simply innate and can be modified by experience
nor is behaviour as fixed as implied by the term ‘fixed action pattern’ — there are subtle variations between members of the same species in the production of aggressive behaviours
this suggests that patterns of aggressive behaviour are not as fixed as Lorenz claimed which challenges the ethological explanation of aggression and means it might be limited in its ability to explain aggressive behaviour
