The ethological explanation of aggression

  • The ethological explanation of aggression:
  • AO1:
  • Aggression is adaptive the reduce competition and establish dominance:
  • Aggression is beneficial to survival because it 1) reduces competition because a defeated animal is rarely killed but instead forced into trritory elsewhere, reducing competition pressure, 2) establishes dominance hierarchies. For example, a male chimpanzee's dominance gives him special status, inclusing mating rights over females. 
  • Pettit et al observed how aggression in playgroups played an important role in how some chuildren became dominant over others - this is adaptive (therefore naturally selected) because dominance over others brings benefits. 
  • Much aggression is realisitic - a series of behaviours carried out in a set order:
  • Lorenz observed most intra-species aggression consisted mainly of riualistic signalling (e.g. displaying teeth) and rarely became physical. Intra-species aggression usually ends with an appeasement display - indicates acceptance of defeat and inhibits aggression in the winner, preventing damage to the loser. This is adaptive as every aggressive encounter ending with the death of an individula could threaten the existance of the species. 
  • IRM is triggered by an environmental stimulus:
  • An innate releasing mechanism (IRM) is a built in psysiological preocess or structure (e.g. network of neurons in the brain). It acts as a 'filter' to identify threatening stimuli in the environment. An environmental stimulus (e.g. facial expression) activates the IRM. It triggers or 'releases' a fixed actiobn pattern (FAP). 
  • FAP is ritualistic, universal and ballistic:
  • A fixed action pattern (FAP) is a pattern of behaviours triggered by an IRM. Lea argues that an FAP is a relativelty unchanging behavioural sequence (ritualisitc) found in every individual of a species (universal) and follows an inevitable course which cannot be altered before it is completed (ballistic). 
  • Key


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