Ethological explanation for aggression

Question 1

What does the ethological explanation seek to undertsand?

Answer 1

• seeks to understand the innate behaviour of animals by studying them in their natural environments

Question 2

What are the two key elements of the ethological approach?

Answer 2

• aggression is an instinct
• is innate and mostly genetically determined

Question 3

What does the ethological approach suggests the main function of aggression is?

Answer 3

• adaptive

Question 4

What is the first adaptive function of aggression?

Answer 4

1) reduces competition pressure & possibility of starvation
- a defeated animal is rarely killed but forced to establish territory elsewhere > beneficial to survival
- means that members of a species spread out over a wider area & have to discover resources in a different place

Question 5

What is the second adaptive function of aggression?

Answer 5

2) helps to establish dominance hierarchies
- male chimpanzees use aggression to climb their troop’s social hierarchy> dominance gives them special status (e.g. mating rights over females)

Question 6

Explain study that found dominance hierarchies in humans

Answer 6

• Pettit et al
• studied groups of young children & observed how aggression played an important role in development of DH
  = adaptive > dominance over others brings benefits such as first access to resources

Question 7

What is an example of aggression that is adaptive?

Answer 7

• ritualistic aggression

Question 8

What is a ritual?

Answer 8

• series of behaviours carried out in a set order

Question 9

What did Lorenz observe?

Answer 9

• that fights between animals of the same species produced little actual physical damage
• but aggressive encounters consisted of a prolonged period of ritualistic signalling
  e.g. displaying claws, teeth

Question 10

What did Lorenz argue aggressive confrontations end with?

Answer 10

• ritual appeasement displays
• these indicate acceptance of defeat & inhibit any further aggressive behaviour in the victor, preventing any damage to the loser
  e.g. wolf will expose its neck to the victor

Question 11

How is ritualistic aggression adaptive?

Answer 11

• enables members of species to compete & establish dominance without actually harming each other as this would threaten existence of species

Question 12

What are the examples of innate aggression?

Answer 12

IRMs and FAPs

Question 13

What is an innate releasing mechanism (IRM)?

Answer 13

• A inbuilt biological structure or process
• an environmental stimulus triggers the IRM which then releases a specific sequence of behaviours (FAPs)

Question 14

What is a fixed action pattern (FAPs)?

Answer 14

• a sequence of stereotyped programmed behaviours triggered by an IRM

Question 15

What are the six main features of FAPs according to Lea?

Answer 15

• Stereotyped, relatively unchanging sequence of behaviours
• Universal, same behaviour found in every individual of a species
• Unaffected by learning, same for every individual regardless of experience
• Ballistic, once behaviour triggered cannot be altered until behaviour is complete
• single-purpose, only occurs in a specific situation, no other
• response to specific sign stimulus

Question 16

What does Tinbergens research demonstrate?

Answer 16

• How FAPs in sticklebacks are universal

Question 17

What are sticklebacks like during the mating season?

Answer 17

• are highly territorial, build nests where females lay eggs
• also develop red bellies during this time
• If another male enters their territory, the stickleback will attack > FAPs are initiated
• sign stimulus that triggers IRM is the sight of red spot

Question 18

What was Tinbergen’s research procedure?

Answer 18

• Male sticklebacks were presented with a series of wooden models of different shapes

Question 19

What was Tinbergen’s research findings?

Answer 19

• regardless of the shape, if the model had a red spot the male stickleback would attack it
• All responded with the same FAP of fighting behaviour (universal>innate)
• FAP always ran its course to completion once triggered

Question 20

What is a strength of the ethological explanation?

Answer 20

• support from research related to genetics
• e.g. Brunner et al’s study>MAOA-L gene is closely associated with aggressive behaviours in humans
• Twin & adoption studies> significant genetic component to aggression in humans
• point to innate basis to aggressive behaviour
• E approach correct in claiming aggression is genetically determined, adaptive & heritable

Question 21

What is a counter point for research supporting genetic basis?

Answer 21

• aggressive behaviours differ from one culture to another
• Nisbett> one type of homicide was more common in white men in the Southern US than in the northern US
• concluded that difference was caused by a ‘culture of honour’ in the southern US> less prevalent in North
• aggressive behaviour comes from learned social norms rather than innate
• culture can override innate predispositions

Question 22

What conflicting research is there for ritualistic aggression?

Answer 22

• aggression against members of the same species is not ritualistic
• Goodall observed a ‘four year war’ in which male chimps from one community killed all the members of another group
• did this is a systematic way
• victim held down by rival chimps while others hit it in an attack lasting many minutes
• violence continued even when victims offered appeasement signals (did not inhibit aggression)
• challenges E approach that aggression is a harmless ritual in same species

Question 23

What is a limitation of fixed action patterns?

Answer 23

• Lorenz’s original view of FAPs is outdated > saw them as innate & unchanging
• Hunt> FAPs are actually greatly influenced by environmental factors & learning experiences
• e.g. duration of each behaviour in a sequence varies from one individual to another
• Modifiable by experience, so ethologists prefer the term ‘Modal behaviour pattern’ to reflect this
• patterns of aggressive behaviour much more flexible