ethology and aggression

Question 1

2 reasons why is aggression beneficial to survival

Answer 1

1. it reduces competition
2. establishes dominance hierarchies and these are vital to allow access to resources such as females

Question 2

support of aggression establishing dominance hierarchies

Answer 2

Pettit et al observed how aggression in children at play led to dominance hierarchies - this is adaptive because dominance over others brings benefits

Question 3

ritualistic aggression - Lorenz

Answer 3

Lorenz proposed that aggression in animals is often ritualistic, which he argued is more adaptive than direct aggression, as symbolic aggression would help ensure that organism was not harmed.
if the organism sustained an injury this could impair their ability to reproduce or even result in death.
So ritualistic aggression such as ‘teeth bearing’ would have the effect of deterring an opponent without causing physical harm.

Question 4

what is an innate releasing mechanism

Answer 4

an inbuilt physiological process.
A Key Stimulus triggers/activates the innate releasing mechanism which produces the Fixed Action Pattern

Question 5

what is a Fixed Action Pattern

Answer 5

FAP is a pattern of instinctive behaviours triggered by an IRM.
They are a sequence of actions that respond to a stressor or cue (Stimulus). FAP’s are innate and must be performed to their fullest extent, even when the stimulus is no longer present. Cannot be altered before it is completed. Found in every individual of a species (universal)

Question 6

Lea three features of FAPs

Answer 6

1. universal - all the animals in that species use the same type of threat.
2. Innate - all the animals in that species seem to be born with it and dont have to learn it
3. Ballistic - once it starts it cannot
   be stopped

Question 7

Key study for IRMs and FAPs:
Tinbergen - The Stickleback study

Answer 7

Tinbergen - The Stickleback study:
- Tinbergen presented male sticklebacks with a series of wooden models of different shapes.
The red on the competing males’ underbelly is the stimulus that triggers the IRM that, in turn, leads to aggressive FAP.
He found that if the model had a red underside, the stickleback would aggressively attack it, but no red meant no aggression.
Once triggered, the FAP always ran its course to completion without any further stimulus.

Question 8

research showing a limitation of ethological explanation

Answer 8

Mead - studied three tribes in Papa New Guinea for 6 months. Found the Mundugamor tribe were aggressive excannibals. But the Arapesh tribe were gentle and no aggression found.
Proves aggression is not innate as both tribes would have both been aggressive, not one aggressive and one non aggressive.
Shows that environmental influences like culture affect aggression.

Question 9

Research showing limitation of ethological explanation - NIsbett

Answer 9

Nisbett:
Found that in a lab experiment when South American white males were insulted they were more likely to respond aggressively than white North American males under the same conditions.

problem for ethological explanation of aggression because it demonstrates cultural differences that would be problematic for the ethological explanation to account for as there was a high variation in aggressive responses.

Question 10

Limitation animal study to show aggression is not always ritualistic - Goodall

Answer 10

Goodall studied chimpanzee behaviour for over 50 years. SHe observed groups of chimpanzees that slaughtered all members of the other groups. Goodall referred to this as gang behaviour as the systematic slaughtering of one group by another group. This aggression is hard to explain by an ethological explanation as the risk of injury to the attacking group is high and thus does not appear to be adaptive behaviour. - not a harmless ritualistic aggression