ethological explanation of aggression

• adaptive function of aggression:

  • lorenz - main function of aggression is adaptive
  • aggression beneficial to survival - defeated animal rarely killed to establish territory, reduces resource competition
  • adaptive function - dominance hierarchy + provides special status
• ritualistic aggression:

  • lorenz - little actual physical damage done
  • ritualistic signalling e.g showing teeth, claws - allows for assessment of relative strength
  • confrontations often end with appeasement displays - acceptance of defeat + inhibit aggressive behaviour
• innate releasing mechanisms (IRM):

  • biological structure or process activated by a sign stimulus that triggers FAP
• fixed action patterns (FAP):

  • sequence of stereotyped programmed behaviours triggered by IRM
• characteristics of FAPs (lea):

  • stereotyped - occurs in the same way
  • universal - applied to all species
  • unaffected by learning - same for each animal
  • ballistic - cant stop/be changed
  • single purpose - occurs in specific situation
  • specific sensory stimuli
• tinbergen:

  • procedure - sticklebacks with wooden model shapes
  • findings - if it had red stomach, stickleback would display aggressive FAP and attack
  • no red spot - no attack even if it looked more like a fish
  • FAPs were stereotyped, universal + ballistic
• EVALUATION: research support

  • kluver + bucy - amygdala in dominant monkeys destroyed, lost place in hierarchy
  • like in humans, behaviour was innate - support for IRMs
  • increased validity, evidence for genetic + physiological basis
• EVALUATION: ignores nurture

  • environmental factors result of learning, experience interacts with innate factors
  • FAP replaced by behaviour pattern - not simply innate can change, behaviour isnt fixed
  • patterns of behaviour arent fixed as lorenz claims, decreases validity
• EVALUATION: evidence against ritualistic aggression

  • goodall - chimps in gombe stream national park, chimps slaughtered group of chimps, premeditated
  • violence continued despite signals of appeasement
  • signals didnt inhibit behaviour, casts doubt on theory