The ethnological explanation of aggresssion

• Ethnological explanation


  This is an explanation that seeks to understand the innate behaviour of animals by studying them in their natural environment.
• Ethnological explanation suggests…


  The main function of aggression is adaptive.
• Adaptive functions of aggression


  Aggression is beneficial to survival because a defeated animal is rarely killed and instead is forced to move to another territory. This means that members of that species spread out over a wider area and have to discover resources in a different place which reduces competition and possibility of starvation.
• Another adaptive function of aggression is…


  To establish dominance hierarchies. Male chimpanzees use aggression to climb to their troops social hierarch. Dominance gives them special status like mating rights over females.
• Adaptive function of aggression: dominance hierarchy 


  Pettit et al studied groups of young children and observed how aggression played n important role in the development of dominance hierarchies. This would be adaptive because dominance over others brings benefits like access to resources like food and mates.
• Ritualistic aggression- Lorenz


  Lorenz observed that fights of the same species produced little actual physical damage. Most aggressive encounters consisted of a prolonged period of ritualistic signalling like displaying claws and teeth. Lorenz pointed out that intra-species aggressive confrontation end with ritual displays. These indicate acceptance of defeat and inhibit further aggressive behaviour in the victor preventing any damage to the loser. This is adaptive because if every aggressive encounter within species ended with death then the species could go extinct.
• Innate releasing mechanism(IRM)


  An IRM is an inbuilt physiological process or structure for instance a network of neuron’s in the brain. An environmental stimulus triggers the IRM which then releases a specific sequence of behaviour. The behavioural sequence is called a fixed action pattern.
• Fixed action patters (FAPs) - Lea


  FAPs have 6 main features:
• 6 main features of FAPs- Lea

  • Stereotyped or relatively unchanging sequences of behaviour
  • Universal, because the same behaviour is found in every individual of species
  • Unaffected by learning, the same for every individual regardless of experience
  • Ballistic, once behaviour is triggered it follows an inevitable course and cannot be altered before it is completed
  • Single-purpose, the behaviour only occurs in a specific situation and not in any other
  • A response to an identifiable sign stimulus
• Tinbergen’s research- procedure 


  Male sticklebacks are highly territorial during the spring mating season, when they also develop a red spot on their underbelly. If another male enters their territory, a sequence of highly-stereotyped aggressive behaviours are initiated(FAP). The sign stimulus that triggers the innate releasing mechanism is the sight of the red spot. Tinbergen presented sticklebacks with a series of wooden models of different shapes.
• Tinbergens research- findings


  Regardless of the shape, if the model had a red spot the male stickleback would aggressively display and even attack it. But if there was no red spot there was no aggression, even if the model looked realistically like the stickleback. Tinbergen 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 one strength of the evaluation related to aggression research?

  Support from research related to genetics and evolution
• What did Brunner et al.'s study find about the MAOA-L gene?

  It is closely associated with aggressive behaviour in humans
• What do twin and adoption studies indicate about aggression in humans?

  There is a significant genetic component to aggression
• What did Wilson and Daly find regarding aggression?

  Aggression is an adaptive behaviour and genetically based
• What do the findings of Brunner et al., twin and adoption studies, and Wilson and Daly suggest about aggressive behaviour?

  They show the innate basis to aggressive behaviour
• What does the theological approach claim about aggression?

  Aggression is genetically determined, heritable, and adaptive
• What are the key findings from research on genetics and aggression?

  • MAOA-L gene linked to aggressive behaviour
  • Significant genetic component to aggression shown in twin and adoption studies
  • Aggression identified as an adaptive behaviour by Wilson and Daly
• Limitation- cultural differences 


  However, aggressive behaviour differed from one culture to another sometimes even within the same country. Nisbett found that one type of homicide, result of reactive aggression, was more common amongst white men in south US. Reactive aggression is a response to threats from someone else. Nisbett concluded that the difference was cause by a culture of honour within Southern US. This is less prevalent in the north which is why reactive aggression homicide rates are lower there. So this aggressive behaviour comes from a learned social norm instead of instinct.
• Limitation- Ritualistic aggression


  One limitation is that aggression against members of the same species is not just ritualistic. Goodall observed a war where male chimps from one community killed all the members of another group, they would do it systematically by holding down victims and attacking even though victims gave appeasement signals. These signals didn’t stop the aggression going against the ethnological explanation. This challenges the ethnological view that same species aggression has evolved into a self limiting and relatively harmless ritual.
• Limitation- FAPs are not fixed 


  Another limitation is that Lorenzs original view of FAPs is outdated. He saw FAPs as innate and unchanging, but hunt said that FAPs are actually greatly influenced by environmental factors and learning experiences. For instance an aggressive FAP is typically made up of several behaviours in a series. The duration of each behaviour varies from one individual to another because they are modifiable by experience, modal behaviour patterns. Therefore patterns of aggressive behaviour are much more flexible than Lorenz thought especially in humans.