ETHOLOGICAL EXPLANATIONS

• SIGN STIMULUS?

  environmental feature triggering an innate releasing mechanism
• INNATE RELEASING MECHANISM?

  hard-wired brain networks that respond to sign stimuli and initiate fixed action patterns
• FIXED ACTION PATTERNS?

  stereotyped sequence of behaviours carried out until completion

  • universal
  • single-purpose
  • stereotyped
  • innate
  • responsive
  • run their course until complete
• RITUALISTIC AGGRESSION?

  • not all aggressive behaviour involves fighting
  • some in form of threat displays
  • assess relative strength before escalating conflict
  • e.g. male gorillas hoot and chest pound to intimidate opponents
• EVALUATION

  + Tinbergen

  -extrapolation

  -Nisbett

  -social learning approach
• TINBERGEN?

  • male sticklebacks
  • attacks other male sticklebacks with head (fixed action pattern)
  • when enter territory
  • in response to seeing red belly (sign stimulus)
  • however if the belly was covered the male stickleback would not attack
• EXTRAPOLATION?

  • humans more influenced by social factors
  • have a lack of fixed action processes due to culture
  • flexibility of human behaviour and ability to respond to ever-changing environment more effective than stereotypical fixed patterns
  • not adaptive in modern times (environment rapidly changes)
• NISBETT?

  • laboratory experiment
  • South American white males more likely to respond aggressively to insult than North American white males
  • cultural differences suggests that aggression is not purely innate
• SOCIAL LEARNING APPROACH?

  • not all fixed action processes are fixed
  • learning and environmental factors create variation within a species
  • modal action patterns are more relevant (instinctual but differ between individuals in a species)
  • e.g. chasing in dogs (prey drive) and there are differences due to training/ species differentiation/ selective breeding of characteristics